Commit Graph

10846 Commits

Author SHA1 Message Date
Thomas Gleixner b2681e791d x86/fpu: Rename and sanitize fpu__save/copy()
Both function names are a misnomer.

fpu__save() is actually about synchronizing the hardware register state
into the task's memory state so that either coredump or a math exception
handler can inspect the state at the time where the problem happens.

The function guarantees to preserve the register state, while "save" is a
common terminology for saving the current state so it can be modified and
restored later. This is clearly not the case here.

Rename it to fpu_sync_fpstate().

fpu__copy() is used to clone the current task's FPU state when duplicating
task_struct. While the register state is a copy the rest of the FPU state
is not.

Name it accordingly and remove the really pointless @src argument along
with the warning which comes along with it.

Nothing can ever copy the FPU state of a non-current task. It's clearly
just a consequence of arch_dup_task_struct(), but it makes no sense to
proliferate that further.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121455.196727450@linutronix.de
2021-06-23 18:55:56 +02:00
Dave Hansen 784a46618f x86/pkeys: Move read_pkru() and write_pkru()
write_pkru() was originally used just to write to the PKRU register.  It
was mercifully short and sweet and was not out of place in pgtable.h with
some other pkey-related code.

But, later work included a requirement to also modify the task XSAVE
buffer when updating the register.  This really is more related to the
XSAVE architecture than to paging.

Move the read/write_pkru() to asm/pkru.h.  pgtable.h won't miss them.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121455.102647114@linutronix.de
2021-06-23 18:52:57 +02:00
Thomas Gleixner a75c52896b x86/fpu/xstate: Sanitize handling of independent features
The copy functions for the independent features are horribly named and the
supervisor and independent part is just overengineered.

The point is that the supplied mask has either to be a subset of the
independent features or a subset of the task->fpu.xstate managed features.

Rewrite it so it checks for invalid overlaps of these areas in the caller
supplied feature mask. Rename it so it follows the new naming convention
for these operations. Mop up the function documentation.

This allows to use that function for other purposes as well.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lkml.kernel.org/r/20210623121455.004880675@linutronix.de
2021-06-23 18:46:20 +02:00
Andy Lutomirski 01707b6653 x86/fpu: Rename "dynamic" XSTATEs to "independent"
The salient feature of "dynamic" XSTATEs is that they are not part of the
main task XSTATE buffer.  The fact that they are dynamically allocated is
irrelevant and will become quite confusing when user math XSTATEs start
being dynamically allocated.  Rename them to "independent" because they
are independent of the main XSTATE code.

This is just a search-and-replace with some whitespace updates to keep
things aligned.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/1eecb0e4f3e07828ebe5d737ec77dc3b708fad2d.1623388344.git.luto@kernel.org
Link: https://lkml.kernel.org/r/20210623121454.911450390@linutronix.de
2021-06-23 18:42:11 +02:00
Thomas Gleixner 1c61fada30 x86/fpu: Rename copy_kernel_to_fpregs() to restore_fpregs_from_fpstate()
This is not a copy functionality. It restores the register state from the
supplied kernel buffer.

No functional changes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121454.716058365@linutronix.de
2021-06-23 18:36:42 +02:00
Thomas Gleixner 08ded2cd18 x86/fpu: Get rid of the FNSAVE optimization
The FNSAVE support requires conditionals in quite some call paths because
FNSAVE reinitializes the FPU hardware. If the save has to preserve the FPU
register state then the caller has to conditionally restore it from memory
when FNSAVE is in use.

This also requires a conditional in context switch because the restore
avoidance optimization cannot work with FNSAVE. As this only affects 20+
years old CPUs there is really no reason to keep this optimization
effective for FNSAVE. It's about time to not optimize for antiques anymore.

Just unconditionally FRSTOR the save content to the registers and clean up
the conditionals all over the place.

Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121454.617369268@linutronix.de
2021-06-23 18:29:41 +02:00
Thomas Gleixner ebe7234b08 x86/fpu: Rename copy_fpregs_to_fpstate() to save_fpregs_to_fpstate()
A copy is guaranteed to leave the source intact, which is not the case when
FNSAVE is used as that reinitilizes the registers.

Save does not make such guarantees and it matches what this is about,
i.e. to save the state for a later restore.

Rename it to save_fpregs_to_fpstate().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121454.508853062@linutronix.de
2021-06-23 18:26:43 +02:00
Thomas Gleixner 1cc34413ff x86/fpu: Rename xstate copy functions which are related to UABI
Rename them to reflect that these functions deal with user space format
XSAVE buffers.

      copy_kernel_to_xstate() -> copy_uabi_from_kernel_to_xstate()
      copy_user_to_xstate()   -> copy_sigframe_from_user_to_xstate()

Again a clear statement that these functions deal with user space ABI.

Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121454.318485015@linutronix.de
2021-06-23 18:23:14 +02:00
Thomas Gleixner 6fdc908cb5 x86/fpu: Rename fregs-related copy functions
The function names for fnsave/fnrstor operations are horribly named and
a permanent source of confusion.

Rename:
	copy_kernel_to_fregs() to frstor()
	copy_fregs_to_user()   to fnsave_to_user_sigframe()
	copy_user_to_fregs()   to frstor_from_user_sigframe()

so it's clear what these are doing. All these functions are really low
level wrappers around the equally named instructions, so mapping to the
documentation is just natural.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121454.223594101@linutronix.de
2021-06-23 18:20:27 +02:00
Thomas Gleixner 16dcf43859 x86/fpu: Rename fxregs-related copy functions
The function names for fxsave/fxrstor operations are horribly named and
a permanent source of confusion.

Rename:
	copy_fxregs_to_kernel() to fxsave()
	copy_kernel_to_fxregs() to fxrstor()
	copy_fxregs_to_user() to fxsave_to_user_sigframe()
	copy_user_to_fxregs() to fxrstor_from_user_sigframe()

so it's clear what these are doing. All these functions are really low
level wrappers around the equally named instructions, so mapping to the
documentation is just natural.

While at it, replace the static_cpu_has(X86_FEATURE_FXSR) with
use_fxsr() to be consistent with the rest of the code.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121454.017863494@linutronix.de
2021-06-23 18:12:30 +02:00
Thomas Gleixner 6b862ba182 x86/fpu: Rename copy_user_to_xregs() and copy_xregs_to_user()
The function names for xsave[s]/xrstor[s] operations are horribly named and
a permanent source of confusion.

Rename:
	copy_xregs_to_user() to xsave_to_user_sigframe()
	copy_user_to_xregs() to xrstor_from_user_sigframe()

so it's entirely clear what this is about. This is also a clear indicator
of the potentially different storage format because this is user ABI and
cannot use compacted format.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.924266705@linutronix.de
2021-06-23 18:01:56 +02:00
Thomas Gleixner b16313f71c x86/fpu: Rename copy_xregs_to_kernel() and copy_kernel_to_xregs()
The function names for xsave[s]/xrstor[s] operations are horribly named and
a permanent source of confusion.

Rename:
	copy_xregs_to_kernel() to os_xsave()
	copy_kernel_to_xregs() to os_xrstor()

These are truly low level wrappers around the actual instructions
XSAVE[OPT]/XRSTOR and XSAVES/XRSTORS with the twist that the selection
based on the available CPU features happens with an alternative to avoid
conditionals all over the place and to provide the best performance for hot
paths.

The os_ prefix tells that this is the OS selected mechanism.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.830239347@linutronix.de
2021-06-23 17:57:57 +02:00
Thomas Gleixner 1f3171252d x86/fpu: Get rid of copy_supervisor_to_kernel()
If the fast path of restoring the FPU state on sigreturn fails or is not
taken and the current task's FPU is active then the FPU has to be
deactivated for the slow path to allow a safe update of the tasks FPU
memory state.

With supervisor states enabled, this requires to save the supervisor state
in the memory state first. Supervisor states require XSAVES so saving only
the supervisor state requires to reshuffle the memory buffer because XSAVES
uses the compacted format and therefore stores the supervisor states at the
beginning of the memory state. That's just an overengineered optimization.

Get rid of it and save the full state for this case.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.734561971@linutronix.de
2021-06-23 17:53:31 +02:00
Thomas Gleixner 02b93c0b00 x86/fpu: Get rid of using_compacted_format()
This function is pointlessly global and a complete misnomer because it's
usage is related to both supervisor state checks and compacted format
checks. Remove it and just make the conditions check the XSAVES feature.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.425493349@linutronix.de
2021-06-23 17:49:47 +02:00
Thomas Gleixner dbb60ac764 x86/fpu: Move fpu__write_begin() to regset
The only usecase for fpu__write_begin is the set() callback of regset, so
the function is pointlessly global.

Move it to the regset code and rename it to fpu_force_restore() which is
exactly decribing what the function does.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.328652975@linutronix.de
2021-06-23 17:49:47 +02:00
Thomas Gleixner 5a32fac8db x86/fpu/regset: Move fpu__read_begin() into regset
The function can only be used from the regset get() callbacks safely. So
there is no reason to have it globally exposed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.234942936@linutronix.de
2021-06-23 17:49:47 +02:00
Thomas Gleixner afac9e8943 x86/fpu: Remove fpstate_sanitize_xstate()
No more users.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.124819167@linutronix.de
2021-06-23 17:49:47 +02:00
Thomas Gleixner eb6f51723f x86/fpu: Make copy_xstate_to_kernel() usable for [x]fpregs_get()
When xsave with init state optimization is used then a component's state
in the task's xsave buffer can be stale when the corresponding feature bit
is not set.

fpregs_get() and xfpregs_get() invoke fpstate_sanitize_xstate() to update
the task's xsave buffer before retrieving the FX or FP state. That's just
duplicated code as copy_xstate_to_kernel() already handles this correctly.

Add a copy mode argument to the function which allows to restrict the state
copy to the FP and SSE features.

Also rename the function to copy_xstate_to_uabi_buf() so the name reflects
what it is doing.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121452.805327286@linutronix.de
2021-06-23 17:49:47 +02:00
Thomas Gleixner 43be46e896 x86/fpu: Sanitize xstateregs_set()
xstateregs_set() operates on a stopped task and tries to copy the provided
buffer into the task's fpu.state.xsave buffer.

Any error while copying or invalid state detected after copying results in
wiping the target task's FPU state completely including supervisor states.

That's just wrong. The caller supplied invalid data or has a problem with
unmapped memory, so there is absolutely no justification to corrupt the
target state.

Fix this with the following modifications:

 1) If data has to be copied from userspace, allocate a buffer and copy from
    user first.

 2) Use copy_kernel_to_xstate() unconditionally so that header checking
    works correctly.

 3) Return on error without corrupting the target state.

This prevents corrupting states and lets the caller deal with the problem
it caused in the first place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121452.214903673@linutronix.de
2021-06-23 17:49:46 +02:00
Thomas Gleixner e68524456c x86/fpu: Move inlines where they belong
They are only used in fpstate_init() and there is no point to have them in
a header just to make reading the code harder.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121452.023118522@linutronix.de
2021-06-23 17:49:46 +02:00
Thomas Gleixner 4098b3eef3 x86/fpu: Remove unused get_xsave_field_ptr()
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121451.915614415@linutronix.de
2021-06-23 17:49:46 +02:00
Thomas Gleixner ce38f038ed x86/fpu: Get rid of fpu__get_supported_xfeatures_mask()
This function is really not doing what the comment advertises:

 "Find supported xfeatures based on cpu features and command-line input.
  This must be called after fpu__init_parse_early_param() is called and
  xfeatures_mask is enumerated."

fpu__init_parse_early_param() does not exist anymore and the function just
returns a constant.

Remove it and fix the caller and get rid of further references to
fpu__init_parse_early_param().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121451.816404717@linutronix.de
2021-06-23 17:49:46 +02:00
Borislav Petkov c4cf5f6198 Merge x86/urgent into x86/fpu
Pick up dependent changes which either went mainline (x86/urgent is
based on -rc7 and that contains them) as urgent fixes and the current
x86/urgent branch which contains two more urgent fixes, so that the
bigger FPU rework can base off ontop.

Signed-off-by: Borislav Petkov <bp@suse.de>
2021-06-23 17:43:38 +02:00
Paolo Bonzini c3ab0e28a4 Merge branch 'topic/ppc-kvm' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux into HEAD
- Support for the H_RPT_INVALIDATE hypercall

- Conversion of Book3S entry/exit to C

- Bug fixes
2021-06-23 07:30:41 -04:00
Brijesh Singh 310f134ed4 x86/sev: Add defines for GHCB version 2 MSR protocol requests
Add the necessary defines for supporting the GHCB version 2 protocol.
This includes defines for:

	- MSR-based AP hlt request/response
	- Hypervisor Feature request/response

This is the bare minimum of requests that need to be supported by a GHCB
version 2 implementation. There are more requests in the specification,
but those depend on Secure Nested Paging support being available.

These defines are shared between SEV host and guest support.

  [ bp: Fold in https://lkml.kernel.org/r/20210622144825.27588-2-joro@8bytes.org too.
        Simplify the brewing macro maze into readability. ]

Co-developed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/YNLXQIZ5e1wjkshG@8bytes.org
2021-06-23 11:25:17 +02:00
Peter Zijlstra 1f008d46f1 x86: Always inline task_size_max()
Fix:

  vmlinux.o: warning: objtool: handle_bug()+0x10: call to task_size_max() leaves .noinstr.text section

When #UD isn't a BUG, we shouldn't violate noinstr (we'll still
probably die, but that's another story).

Fixes: 025768a966 ("x86/cpu: Use alternative to generate the TASK_SIZE_MAX constant")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210621120120.682468274@infradead.org
2021-06-22 13:56:43 +02:00
Thomas Gleixner f9dfb5e390 x86/fpu: Make init_fpstate correct with optimized XSAVE
The XSAVE init code initializes all enabled and supported components with
XRSTOR(S) to init state. Then it XSAVEs the state of the components back
into init_fpstate which is used in several places to fill in the init state
of components.

This works correctly with XSAVE, but not with XSAVEOPT and XSAVES because
those use the init optimization and skip writing state of components which
are in init state. So init_fpstate.xsave still contains all zeroes after
this operation.

There are two ways to solve that:

   1) Use XSAVE unconditionally, but that requires to reshuffle the buffer when
      XSAVES is enabled because XSAVES uses compacted format.

   2) Save the components which are known to have a non-zero init state by other
      means.

Looking deeper, #2 is the right thing to do because all components the
kernel supports have all-zeroes init state except the legacy features (FP,
SSE). Those cannot be hard coded because the states are not identical on all
CPUs, but they can be saved with FXSAVE which avoids all conditionals.

Use FXSAVE to save the legacy FP/SSE components in init_fpstate along with
a BUILD_BUG_ON() which reminds developers to validate that a newly added
component has all zeroes init state. As a bonus remove the now unused
copy_xregs_to_kernel_booting() crutch.

The XSAVE and reshuffle method can still be implemented in the unlikely
case that components are added which have a non-zero init state and no
other means to save them. For now, FXSAVE is just simple and good enough.

  [ bp: Fix a typo or two in the text. ]

Fixes: 6bad06b768 ("x86, xsave: Use xsaveopt in context-switch path when supported")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210618143444.587311343@linutronix.de
2021-06-22 11:06:21 +02:00
Joerg Roedel be1a540886 x86/sev: Split up runtime #VC handler for correct state tracking
Split up the #VC handler code into a from-user and a from-kernel part.
This allows clean and correct state tracking, as the #VC handler needs
to enter NMI-state when raised from kernel mode and plain IRQ state when
raised from user-mode.

Fixes: 62441a1fb5 ("x86/sev-es: Correctly track IRQ states in runtime #VC handler")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210618115409.22735-3-joro@8bytes.org
2021-06-21 16:01:05 +02:00
Ingo Molnar b2c0931a07 Merge branch 'sched/urgent' into sched/core, to resolve conflicts
This commit in sched/urgent moved the cfs_rq_is_decayed() function:

  a7b359fc6a37: ("sched/fair: Correctly insert cfs_rq's to list on unthrottle")

and this fresh commit in sched/core modified it in the old location:

  9e077b52d86a: ("sched/pelt: Check that *_avg are null when *_sum are")

Merge the two variants.

Conflicts:
	kernel/sched/fair.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-06-18 11:31:25 +02:00
Ashish Kalra 0dbb112304 KVM: X86: Introduce KVM_HC_MAP_GPA_RANGE hypercall
This hypercall is used by the SEV guest to notify a change in the page
encryption status to the hypervisor. The hypercall should be invoked
only when the encryption attribute is changed from encrypted -> decrypted
and vice versa. By default all guest pages are considered encrypted.

The hypercall exits to userspace to manage the guest shared regions and
integrate with the userspace VMM's migration code.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Co-developed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <90778988e1ee01926ff9cac447aacb745f954c8c.1623174621.git.ashish.kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 14:25:39 -04:00
Paolo Bonzini e3cb6fa0e2 KVM: switch per-VM stats to u64
Make them the same type as vCPU stats.  There is no reason
to limit the counters to unsigned long.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 14:25:27 -04:00
Sean Christopherson 25b62c6274 KVM: nVMX: Free only guest_mode (L2) roots on INVVPID w/o EPT
When emulating INVVPID for L1, free only L2+ roots, using the guest_mode
tag in the MMU role to identify L2+ roots.  From L1's perspective, its
own TLB entries use VPID=0, and INVVPID is not requied to invalidate such
entries.  Per Intel's SDM, INVVPID _may_ invalidate entries with VPID=0,
but it is not required to do so.

Cc: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:53 -04:00
Sean Christopherson b512910039 KVM: x86: Drop skip MMU sync and TLB flush params from "new PGD" helpers
Drop skip_mmu_sync and skip_tlb_flush from __kvm_mmu_new_pgd() now that
all call sites unconditionally skip both the sync and flush.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:52 -04:00
Sean Christopherson 07ffaf343e KVM: nVMX: Sync all PGDs on nested transition with shadow paging
Trigger a full TLB flush on behalf of the guest on nested VM-Enter and
VM-Exit when VPID is disabled for L2.  kvm_mmu_new_pgd() syncs only the
current PGD, which can theoretically leave stale, unsync'd entries in a
previous guest PGD, which could be consumed if L2 is allowed to load CR3
with PCID_NOFLUSH=1.

Rename KVM_REQ_HV_TLB_FLUSH to KVM_REQ_TLB_FLUSH_GUEST so that it can
be utilized for its obvious purpose of emulating a guest TLB flush.

Note, there is no change the actual TLB flush executed by KVM, even
though the fast PGD switch uses KVM_REQ_TLB_FLUSH_CURRENT.  When VPID is
disabled for L2, vpid02 is guaranteed to be '0', and thus
nested_get_vpid02() will return the VPID that is shared by L1 and L2.

Generate the request outside of kvm_mmu_new_pgd(), as getting the common
helper to correctly identify which requested is needed is quite painful.
E.g. using KVM_REQ_TLB_FLUSH_GUEST when nested EPT is in play is wrong as
a TLB flush from the L1 kernel's perspective does not invalidate EPT
mappings.  And, by using KVM_REQ_TLB_FLUSH_GUEST, nVMX can do future
simplification by moving the logic into nested_vmx_transition_tlb_flush().

Fixes: 41fab65e7c ("KVM: nVMX: Skip MMU sync on nested VMX transition when possible")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:51 -04:00
Maxim Levitsky 158a48ecf7 KVM: x86: avoid loading PDPTRs after migration when possible
if new KVM_*_SREGS2 ioctls are used, the PDPTRs are
a part of the migration state and are correctly
restored by those ioctls.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210607090203.133058-9-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:48 -04:00
Maxim Levitsky 6dba940352 KVM: x86: Introduce KVM_GET_SREGS2 / KVM_SET_SREGS2
This is a new version of KVM_GET_SREGS / KVM_SET_SREGS.

It has the following changes:
   * Has flags for future extensions
   * Has vcpu's PDPTRs, allowing to save/restore them on migration.
   * Lacks obsolete interrupt bitmap (done now via KVM_SET_VCPU_EVENTS)

New capability, KVM_CAP_SREGS2 is added to signal
the userspace of this ioctl.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210607090203.133058-8-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:47 -04:00
Sean Christopherson c7313155bf KVM: x86: Always load PDPTRs on CR3 load for SVM w/o NPT and a PAE guest
Kill off pdptrs_changed() and instead go through the full kvm_set_cr3()
for PAE guest, even if the new CR3 is the same as the current CR3.  For
VMX, and SVM with NPT enabled, the PDPTRs are unconditionally marked as
unavailable after VM-Exit, i.e. the optimization is dead code except for
SVM without NPT.

In the unlikely scenario that anyone cares about SVM without NPT _and_ a
PAE guest, they've got bigger problems if their guest is loading the same
CR3 so frequently that the performance of kvm_set_cr3() is notable,
especially since KVM's fast PGD switching means reloading the same CR3
does not require a full rebuild.  Given that PAE and PCID are mutually
exclusive, i.e. a sync and flush are guaranteed in any case, the actual
benefits of the pdptrs_changed() optimization are marginal at best.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210607090203.133058-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:46 -04:00
Vitaly Kuznetsov 10d7bf1e46 KVM: x86: hyper-v: Cache guest CPUID leaves determining features availability
Limiting exposed Hyper-V features requires a fast way to check if the
particular feature is exposed in guest visible CPUIDs or not. To aboid
looping through all CPUID entries on every hypercall/MSR access cache
the required leaves on CPUID update.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210521095204.2161214-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:38 -04:00
Vitaly Kuznetsov 644f706719 KVM: x86: hyper-v: Introduce KVM_CAP_HYPERV_ENFORCE_CPUID
Modeled after KVM_CAP_ENFORCE_PV_FEATURE_CPUID, the new capability allows
for limiting Hyper-V features to those exposed to the guest in Hyper-V
CPUIDs (0x40000003, 0x40000004, ...).

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210521095204.2161214-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:38 -04:00
Vineeth Pillai 59d21d67f3 KVM: SVM: Software reserved fields
SVM added support for certain reserved fields to be used by
software or hypervisor. Add the following reserved fields:
  - VMCB offset 0x3e0 - 0x3ff
  - Clean bit 31
  - SVM intercept exit code 0xf0000000

Later patches will make use of this for supporting Hyper-V
nested virtualization enhancements.

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
Message-Id: <a1f17a43a8e9e751a1a9cc0281649d71bdbf721b.1622730232.git.viremana@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:37 -04:00
Vineeth Pillai 3c86c0d3db KVM: x86: hyper-v: Move the remote TLB flush logic out of vmx
Currently the remote TLB flush logic is specific to VMX.
Move it to a common place so that SVM can use it as well.

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
Message-Id: <4f4e4ca19778437dae502f44363a38e99e3ef5d1.1622730232.git.viremana@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:36 -04:00
Vineeth Pillai 32431fb253 hyperv: SVM enlightened TLB flush support flag
Bit 22 of HYPERV_CPUID_FEATURES.EDX is specific to SVM and specifies
support for enlightened TLB flush. With this enlightenment enabled,
ASID invalidations flushes only gva->hpa entries. To flush TLB entries
derived from NPT, hypercalls should be used
(HvFlushGuestPhysicalAddressSpace or HvFlushGuestPhysicalAddressList)

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Message-Id: <a060f872d0df1955e52e30b877b3300485edb27c.1622730232.git.viremana@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:36 -04:00
Krish Sadhukhan d5a0483f9f KVM: nVMX: nSVM: Add a new VCPU statistic to show if VCPU is in guest mode
Add the following per-VCPU statistic to KVM debugfs to show if a given
VCPU is in guest mode:

	guest_mode

Also add this as a per-VM statistic to KVM debugfs to show the total number
of VCPUs that are in guest mode in a given VM.

Signed-off-by: Krish Sadhukhan <Krish.Sadhukhan@oracle.com>
Message-Id: <20210609180340.104248-3-krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:36 -04:00
Sean Christopherson ecc513e5bb KVM: x86: Drop "pre_" from enter/leave_smm() helpers
Now that .post_leave_smm() is gone, drop "pre_" from the remaining
helpers.  The helpers aren't invoked purely before SMI/RSM processing,
e.g. both helpers are invoked after state is snapshotted (from regs or
SMRAM), and the RSM helper is invoked after some amount of register state
has been stuffed.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609185619.992058-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:35 -04:00
Vitaly Kuznetsov 4651fc56ba KVM: x86: Drop vendor specific functions for APICv/AVIC enablement
Now that APICv/AVIC enablement is kept in common 'enable_apicv' variable,
there's no need to call kvm_apicv_init() from vendor specific code.

No functional change intended.

Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210609150911.1471882-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:33 -04:00
Vitaly Kuznetsov fdf513e37a KVM: x86: Use common 'enable_apicv' variable for both APICv and AVIC
Unify VMX and SVM code by moving APICv/AVIC enablement tracking to common
'enable_apicv' variable. Note: unlike APICv, AVIC is disabled by default.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210609150911.1471882-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:33 -04:00
Ilias Stamatis 1ab9287add KVM: X86: Add vendor callbacks for writing the TSC multiplier
Currently vmx_vcpu_load_vmcs() writes the TSC_MULTIPLIER field of the
VMCS every time the VMCS is loaded. Instead of doing this, set this
field from common code on initialization and whenever the scaling ratio
changes.

Additionally remove vmx->current_tsc_ratio. This field is redundant as
vcpu->arch.tsc_scaling_ratio already tracks the current TSC scaling
ratio. The vmx->current_tsc_ratio field is only used for avoiding
unnecessary writes but it is no longer needed after removing the code
from the VMCS load path.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
Message-Id: <20210607105438.16541-1-ilstam@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:29 -04:00
Ilias Stamatis edcfe54058 KVM: X86: Move write_l1_tsc_offset() logic to common code and rename it
The write_l1_tsc_offset() callback has a misleading name. It does not
set L1's TSC offset, it rather updates the current TSC offset which
might be different if a nested guest is executing. Additionally, both
the vmx and svm implementations use the same logic for calculating the
current TSC before writing it to hardware.

Rename the function and move the common logic to the caller. The vmx/svm
specific code now merely sets the given offset to the corresponding
hardware structure.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210526184418.28881-9-ilstam@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:29 -04:00
Ilias Stamatis 83150f2932 KVM: X86: Add functions that calculate the nested TSC fields
When L2 is entered we need to "merge" the TSC multiplier and TSC offset
values of 01 and 12 together.

The merging is done using the following equations:
  offset_02 = ((offset_01 * mult_12) >> shift_bits) + offset_12
  mult_02 = (mult_01 * mult_12) >> shift_bits

Where shift_bits is kvm_tsc_scaling_ratio_frac_bits.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210526184418.28881-8-ilstam@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:29 -04:00
Ilias Stamatis 307a94c721 KVM: X86: Add functions for retrieving L2 TSC fields from common code
In order to implement as much of the nested TSC scaling logic as
possible in common code, we need these vendor callbacks for retrieving
the TSC offset and the TSC multiplier that L1 has set for L2.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210526184418.28881-7-ilstam@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:28 -04:00
Ilias Stamatis fe3eb50418 KVM: X86: Add a ratio parameter to kvm_scale_tsc()
Sometimes kvm_scale_tsc() needs to use the current scaling ratio and
other times (like when reading the TSC from user space) it needs to use
L1's scaling ratio. Have the caller specify this by passing the ratio as
a parameter.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210526184418.28881-5-ilstam@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:28 -04:00
Ilias Stamatis 805d705ff8 KVM: X86: Store L1's TSC scaling ratio in 'struct kvm_vcpu_arch'
Store L1's scaling ratio in the kvm_vcpu_arch struct like we already do
for L1's TSC offset. This allows for easy save/restore when we enter and
then exit the nested guest.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210526184418.28881-3-ilstam@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:27 -04:00
Ben Gardon d501f747ef KVM: x86/mmu: Lazily allocate memslot rmaps
If the TDP MMU is in use, wait to allocate the rmaps until the shadow
MMU is actually used. (i.e. a nested VM is launched.) This saves memory
equal to 0.2% of guest memory in cases where the TDP MMU is used and
there are no nested guests involved.

Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210518173414.450044-8-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:27 -04:00
Ben Gardon a255740876 KVM: x86/mmu: Add a field to control memslot rmap allocation
Add a field to control whether new memslots should have rmaps allocated
for them. As of this change, it's not safe to skip allocating rmaps, so
the field is always set to allocate rmaps. Future changes will make it
safe to operate without rmaps, using the TDP MMU. Then further changes
will allow the rmaps to be allocated lazily when needed for nested
oprtation.

No functional change expected.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210518173414.450044-6-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:26 -04:00
Siddharth Chandrasekaran d8f5537a88 KVM: hyper-v: Advertise support for fast XMM hypercalls
Now that kvm_hv_flush_tlb() has been patched to support XMM hypercall
inputs, we can start advertising this feature to guests.

Cc: Alexander Graf <graf@amazon.com>
Cc: Evgeny Iakovlev <eyakovl@amazon.de>
Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de>
Message-Id: <e63fc1c61dd2efecbefef239f4f0a598bd552750.1622019134.git.sidcha@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:24 -04:00
Siddharth Chandrasekaran 5974565bc2 KVM: x86: kvm_hv_flush_tlb use inputs from XMM registers
Hyper-V supports the use of XMM registers to perform fast hypercalls.
This allows guests to take advantage of the improved performance of the
fast hypercall interface even though a hypercall may require more than
(the current maximum of) two input registers.

The XMM fast hypercall interface uses six additional XMM registers (XMM0
to XMM5) to allow the guest to pass an input parameter block of up to
112 bytes.

Add framework to read from XMM registers in kvm_hv_hypercall() and use
the additional hypercall inputs from XMM registers in kvm_hv_flush_tlb()
when possible.

Cc: Alexander Graf <graf@amazon.com>
Co-developed-by: Evgeny Iakovlev <eyakovl@amazon.de>
Signed-off-by: Evgeny Iakovlev <eyakovl@amazon.de>
Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de>
Message-Id: <fc62edad33f1920fe5c74dde47d7d0b4275a9012.1622019134.git.sidcha@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:24 -04:00
Kan Liang 5471eea5d3 perf/x86: Reset the dirty counter to prevent the leak for an RDPMC task
The counter value of a perf task may leak to another RDPMC task.
For example, a perf stat task as below is running on CPU 0.

    perf stat -e 'branches,cycles' -- taskset -c 0 ./workload

In the meantime, an RDPMC task, which is also running on CPU 0, may read
the GP counters periodically. (The RDPMC task creates a fixed event,
but read four GP counters.)

    $./rdpmc_read_all_counters
    index 0x0 value 0x8001e5970f99
    index 0x1 value 0x8005d750edb6
    index 0x2 value 0x0
    index 0x3 value 0x0

    index 0x0 value 0x8002358e48a5
    index 0x1 value 0x8006bd1e3bc9
    index 0x2 value 0x0
    index 0x3 value 0x0

It is a potential security issue. Once the attacker knows what the other
thread is counting. The PerfMon counter can be used as a side-channel to
attack cryptosystems.

The counter value of the perf stat task leaks to the RDPMC task because
perf never clears the counter when it's stopped.

Three methods were considered to address the issue.

 - Unconditionally reset the counter in x86_pmu_del(). It can bring extra
   overhead even when there is no RDPMC task running.

 - Only reset the un-assigned dirty counters when the RDPMC task is
   scheduled in via sched_task(). It fails for the below case.

	Thread A			Thread B

	clone(CLONE_THREAD) --->
	set_affine(0)
					set_affine(1)
					while (!event-enabled)
						;
	event = perf_event_open()
	mmap(event)
	ioctl(event, IOC_ENABLE); --->
					RDPMC

   Counters are still leaked to the thread B.

 - Only reset the un-assigned dirty counters before updating the CR4.PCE
   bit. The method is implemented here.

The dirty counter is a counter, on which the assigned event has been
deleted, but the counter is not reset. To track the dirty counters,
add a 'dirty' variable in the struct cpu_hw_events.

The security issue can only be found with an RDPMC task. To enable the
RDMPC, the CR4.PCE bit has to be updated. Add a
perf_clear_dirty_counters() right before updating the CR4.PCE bit to
clear the existing dirty counters. Only the current un-assigned dirty
counters are reset, because the RDPMC assigned dirty counters will be
updated soon.

After applying the patch,

        $ ./rdpmc_read_all_counters
        index 0x0 value 0x0
        index 0x1 value 0x0
        index 0x2 value 0x0
        index 0x3 value 0x0

        index 0x0 value 0x0
        index 0x1 value 0x0
        index 0x2 value 0x0
        index 0x3 value 0x0

Performance

The performance of a context switch only be impacted when there are two
or more perf users and one of the users must be an RDPMC user. In other
cases, there is no performance impact.

The worst-case occurs when there are two users: the RDPMC user only
uses one counter; while the other user uses all available counters.
When the RDPMC task is scheduled in, all the counters, other than the
RDPMC assigned one, have to be reset.

Test results for the worst-case, using a modified lat_ctx as measured
on an Ice Lake platform, which has 8 GP and 3 FP counters (ignoring
SLOTS).

    lat_ctx -s 128K -N 1000 processes 2

Without the patch:
  The context switch time is 4.97 us

With the patch:
  The context switch time is 5.16 us

There is ~4% performance drop for the context switching time in the
worst-case.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1623693582-187370-1-git-send-email-kan.liang@linux.intel.com
2021-06-17 14:11:47 +02:00
Pawan Gupta 1348924ba8 x86/msr: Define new bits in TSX_FORCE_ABORT MSR
Intel client processors that support the IA32_TSX_FORCE_ABORT MSR
related to perf counter interaction [1] received a microcode update that
deprecates the Transactional Synchronization Extension (TSX) feature.
The bit FORCE_ABORT_RTM now defaults to 1, writes to this bit are
ignored. A new bit TSX_CPUID_CLEAR clears the TSX related CPUID bits.

The summary of changes to the IA32_TSX_FORCE_ABORT MSR are:

  Bit 0: FORCE_ABORT_RTM (legacy bit, new default=1) Status bit that
  indicates if RTM transactions are always aborted. This bit is
  essentially !SDV_ENABLE_RTM(Bit 2). Writes to this bit are ignored.

  Bit 1: TSX_CPUID_CLEAR (new bit, default=0) When set, CPUID.HLE = 0
  and CPUID.RTM = 0.

  Bit 2: SDV_ENABLE_RTM (new bit, default=0) When clear, XBEGIN will
  always abort with EAX code 0. When set, XBEGIN will not be forced to
  abort (but will always abort in SGX enclaves). This bit is intended to
  be used on developer systems. If this bit is set, transactional
  atomicity correctness is not certain. SDV = Software Development
  Vehicle (SDV), i.e. developer systems.

Performance monitoring counter 3 is usable in all cases, regardless of
the value of above bits.

Add support for a new CPUID bit - CPUID.RTM_ALWAYS_ABORT (CPUID 7.EDX[11])
 - to indicate the status of always abort behavior.

[1] [ bp: Look for document ID 604224, "Performance Monitoring Impact
      of Intel Transactional Synchronization Extension Memory". Since
      there's no way for us to have stable links to documents... ]

 [ bp: Massage and extend commit message. ]

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Link: https://lkml.kernel.org/r/9add61915b4a4eedad74fbd869107863a28b428e.1623704845.git-series.pawan.kumar.gupta@linux.intel.com
2021-06-15 17:23:15 +02:00
Thomas Gleixner 510b80a6a0 x86/pkru: Write hardware init value to PKRU when xstate is init
When user space brings PKRU into init state, then the kernel handling is
broken:

  T1 user space
     xsave(state)
     state.header.xfeatures &= ~XFEATURE_MASK_PKRU;
     xrstor(state)

  T1 -> kernel
     schedule()
       XSAVE(S) -> T1->xsave.header.xfeatures[PKRU] == 0
       T1->flags |= TIF_NEED_FPU_LOAD;

       wrpkru();

     schedule()
       ...
       pk = get_xsave_addr(&T1->fpu->state.xsave, XFEATURE_PKRU);
       if (pk)
	 wrpkru(pk->pkru);
       else
	 wrpkru(DEFAULT_PKRU);

Because the xfeatures bit is 0 and therefore the value in the xsave
storage is not valid, get_xsave_addr() returns NULL and switch_to()
writes the default PKRU. -> FAIL #1!

So that wrecks any copy_to/from_user() on the way back to user space
which hits memory which is protected by the default PKRU value.

Assumed that this does not fail (pure luck) then T1 goes back to user
space and because TIF_NEED_FPU_LOAD is set it ends up in

  switch_fpu_return()
      __fpregs_load_activate()
        if (!fpregs_state_valid()) {
  	 load_XSTATE_from_task();
        }

But if nothing touched the FPU between T1 scheduling out and back in,
then the fpregs_state is still valid which means switch_fpu_return()
does nothing and just clears TIF_NEED_FPU_LOAD. Back to user space with
DEFAULT_PKRU loaded. -> FAIL #2!

The fix is simple: if get_xsave_addr() returns NULL then set the
PKRU value to 0 instead of the restrictive default PKRU value in
init_pkru_value.

 [ bp: Massage in minor nitpicks from folks. ]

Fixes: 0cecca9d03 ("x86/fpu: Eager switch PKRU state")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Rik van Riel <riel@surriel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210608144346.045616965@linutronix.de
2021-06-09 12:12:45 +02:00
Thomas Gleixner 12f7764ac6 x86/process: Check PF_KTHREAD and not current->mm for kernel threads
switch_fpu_finish() checks current->mm as indicator for kernel threads.
That's wrong because kernel threads can temporarily use a mm of a user
process via kthread_use_mm().

Check the task flags for PF_KTHREAD instead.

Fixes: 0cecca9d03 ("x86/fpu: Eager switch PKRU state")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210608144345.912645927@linutronix.de
2021-06-09 10:39:04 +02:00
Mike Rapoport 23721c8e92 x86/crash: Remove crash_reserve_low_1M()
The entire memory range under 1M is unconditionally reserved in
setup_arch(), so there is no need for crash_reserve_low_1M() anymore.

Remove this function.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210601075354.5149-4-rppt@kernel.org
2021-06-07 12:14:45 +02:00
Borislav Petkov 0a5f38c81e Linux 5.13-rc5
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Merge tag 'v5.13-rc5' into x86/cleanups

Pick up dependent changes in order to base further cleanups ontop.

Signed-off-by: Borislav Petkov <bp@suse.de>
2021-06-07 11:02:30 +02:00
Linus Torvalds 773ac53bbf - Fix out-of-spec hardware (1st gen Hygon) which does not implement
MSR_AMD64_SEV even though the spec clearly states so, and check CPUID
 bits first.
 
 - Send only one signal to a task when it is a SEGV_PKUERR si_code type.
 
 - Do away with all the wankery of reserving X amount of memory in
 the first megabyte to prevent BIOS corrupting it and simply and
 unconditionally reserve the whole first megabyte.
 
 - Make alternatives NOP optimization work at an arbitrary position
 within the patched sequence because the compiler can put single-byte
 NOPs for alignment anywhere in the sequence (32-bit retpoline), vs our
 previous assumption that the NOPs are only appended.
 
 - Force-disable ENQCMD[S] instructions support and remove update_pasid()
 because of insufficient protection against FPU state modification in an
 interrupt context, among other xstate horrors which are being addressed
 at the moment. This one limits the fallout until proper enablement.
 
 - Use cpu_feature_enabled() in the idxd driver so that it can be
 build-time disabled through the defines in .../asm/disabled-features.h.
 
 - Fix LVT thermal setup for SMI delivery mode by making sure the APIC
 LVT value is read before APIC initialization so that softlockups during
 boot do not happen at least on one machine.
 
 - Mark all legacy interrupts as legacy vectors when the IO-APIC is
 disabled and when all legacy interrupts are routed through the PIC.
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Merge tag 'x86_urgent_for_v5.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:
 "A bunch of x86/urgent stuff accumulated for the last two weeks so
  lemme unload it to you.

  It should be all totally risk-free, of course. :-)

   - Fix out-of-spec hardware (1st gen Hygon) which does not implement
     MSR_AMD64_SEV even though the spec clearly states so, and check
     CPUID bits first.

   - Send only one signal to a task when it is a SEGV_PKUERR si_code
     type.

   - Do away with all the wankery of reserving X amount of memory in the
     first megabyte to prevent BIOS corrupting it and simply and
     unconditionally reserve the whole first megabyte.

   - Make alternatives NOP optimization work at an arbitrary position
     within the patched sequence because the compiler can put
     single-byte NOPs for alignment anywhere in the sequence (32-bit
     retpoline), vs our previous assumption that the NOPs are only
     appended.

   - Force-disable ENQCMD[S] instructions support and remove
     update_pasid() because of insufficient protection against FPU state
     modification in an interrupt context, among other xstate horrors
     which are being addressed at the moment. This one limits the
     fallout until proper enablement.

   - Use cpu_feature_enabled() in the idxd driver so that it can be
     build-time disabled through the defines in disabled-features.h.

   - Fix LVT thermal setup for SMI delivery mode by making sure the APIC
     LVT value is read before APIC initialization so that softlockups
     during boot do not happen at least on one machine.

   - Mark all legacy interrupts as legacy vectors when the IO-APIC is
     disabled and when all legacy interrupts are routed through the PIC"

* tag 'x86_urgent_for_v5.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sev: Check SME/SEV support in CPUID first
  x86/fault: Don't send SIGSEGV twice on SEGV_PKUERR
  x86/setup: Always reserve the first 1M of RAM
  x86/alternative: Optimize single-byte NOPs at an arbitrary position
  x86/cpufeatures: Force disable X86_FEATURE_ENQCMD and remove update_pasid()
  dmaengine: idxd: Use cpu_feature_enabled()
  x86/thermal: Fix LVT thermal setup for SMI delivery mode
  x86/apic: Mark _all_ legacy interrupts when IO/APIC is missing
2021-06-06 12:25:43 -07:00
Peter Collingbourne 92638b4e1b mm: arch: remove indirection level in alloc_zeroed_user_highpage_movable()
In an upcoming change we would like to add a flag to
GFP_HIGHUSER_MOVABLE so that it would no longer be an OR
of GFP_HIGHUSER and __GFP_MOVABLE. This poses a problem for
alloc_zeroed_user_highpage_movable() which passes __GFP_MOVABLE
into an arch-specific __alloc_zeroed_user_highpage() hook which ORs
in GFP_HIGHUSER.

Since __alloc_zeroed_user_highpage() is only ever called from
alloc_zeroed_user_highpage_movable(), we can remove one level
of indirection here. Remove __alloc_zeroed_user_highpage(),
make alloc_zeroed_user_highpage_movable() the hook, and use
GFP_HIGHUSER_MOVABLE in the hook implementations so that they will
pick up the new flag that we are going to add.

Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/Ic6361c657b2cdcd896adbe0cf7cb5a7fbb1ed7bf
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210602235230.3928842-2-pcc@google.com
Signed-off-by: Will Deacon <will@kernel.org>
2021-06-04 19:32:21 +01:00
Ingo Molnar a9e906b71f Merge branch 'sched/urgent' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-06-03 19:00:49 +02:00
Thomas Gleixner 9bfecd0583 x86/cpufeatures: Force disable X86_FEATURE_ENQCMD and remove update_pasid()
While digesting the XSAVE-related horrors which got introduced with
the supervisor/user split, the recent addition of ENQCMD-related
functionality got on the radar and turned out to be similarly broken.

update_pasid(), which is only required when X86_FEATURE_ENQCMD is
available, is invoked from two places:

 1) From switch_to() for the incoming task

 2) Via a SMP function call from the IOMMU/SMV code

#1 is half-ways correct as it hacks around the brokenness of get_xsave_addr()
   by enforcing the state to be 'present', but all the conditionals in that
   code are completely pointless for that.

   Also the invocation is just useless overhead because at that point
   it's guaranteed that TIF_NEED_FPU_LOAD is set on the incoming task
   and all of this can be handled at return to user space.

#2 is broken beyond repair. The comment in the code claims that it is safe
   to invoke this in an IPI, but that's just wishful thinking.

   FPU state of a running task is protected by fregs_lock() which is
   nothing else than a local_bh_disable(). As BH-disabled regions run
   usually with interrupts enabled the IPI can hit a code section which
   modifies FPU state and there is absolutely no guarantee that any of the
   assumptions which are made for the IPI case is true.

   Also the IPI is sent to all CPUs in mm_cpumask(mm), but the IPI is
   invoked with a NULL pointer argument, so it can hit a completely
   unrelated task and unconditionally force an update for nothing.
   Worse, it can hit a kernel thread which operates on a user space
   address space and set a random PASID for it.

The offending commit does not cleanly revert, but it's sufficient to
force disable X86_FEATURE_ENQCMD and to remove the broken update_pasid()
code to make this dysfunctional all over the place. Anything more
complex would require more surgery and none of the related functions
outside of the x86 core code are blatantly wrong, so removing those
would be overkill.

As nothing enables the PASID bit in the IA32_XSS MSR yet, which is
required to make this actually work, this cannot result in a regression
except for related out of tree train-wrecks, but they are broken already
today.

Fixes: 20f0afd1fb ("x86/mmu: Allocate/free a PASID")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/87mtsd6gr9.ffs@nanos.tec.linutronix.de
2021-06-03 16:33:09 +02:00
Andrew Cooper cbcddaa33d perf/x86/rapl: Use CPUID bit on AMD and Hygon parts
AMD and Hygon CPUs have a CPUID bit for RAPL.  Drop the fam17h suffix as
it is stale already.

Make use of this instead of a model check to work more nicely in virtual
environments where RAPL typically isn't available.

 [ bp: drop the ../cpu/powerflags.c hunk which is superfluous as the
   "rapl" bit name appears already in flags. ]

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210514135920.16093-1-andrew.cooper3@citrix.com
2021-06-01 21:10:33 +02:00
Borislav Petkov 9a90ed065a x86/thermal: Fix LVT thermal setup for SMI delivery mode
There are machines out there with added value crap^WBIOS which provide an
SMI handler for the local APIC thermal sensor interrupt. Out of reset,
the BSP on those machines has something like 0x200 in that APIC register
(timestamps left in because this whole issue is timing sensitive):

  [    0.033858] read lvtthmr: 0x330, val: 0x200

which means:

 - bit 16 - the interrupt mask bit is clear and thus that interrupt is enabled
 - bits [10:8] have 010b which means SMI delivery mode.

Now, later during boot, when the kernel programs the local APIC, it
soft-disables it temporarily through the spurious vector register:

  setup_local_APIC:

  	...

	/*
	 * If this comes from kexec/kcrash the APIC might be enabled in
	 * SPIV. Soft disable it before doing further initialization.
	 */
	value = apic_read(APIC_SPIV);
	value &= ~APIC_SPIV_APIC_ENABLED;
	apic_write(APIC_SPIV, value);

which means (from the SDM):

"10.4.7.2 Local APIC State After It Has Been Software Disabled

...

* The mask bits for all the LVT entries are set. Attempts to reset these
bits will be ignored."

And this happens too:

  [    0.124111] APIC: Switch to symmetric I/O mode setup
  [    0.124117] lvtthmr 0x200 before write 0xf to APIC 0xf0
  [    0.124118] lvtthmr 0x10200 after write 0xf to APIC 0xf0

This results in CPU 0 soft lockups depending on the placement in time
when the APIC soft-disable happens. Those soft lockups are not 100%
reproducible and the reason for that can only be speculated as no one
tells you what SMM does. Likely, it confuses the SMM code that the APIC
is disabled and the thermal interrupt doesn't doesn't fire at all,
leading to CPU 0 stuck in SMM forever...

Now, before

  4f432e8bb1 ("x86/mce: Get rid of mcheck_intel_therm_init()")

due to how the APIC_LVTTHMR was read before APIC initialization in
mcheck_intel_therm_init(), it would read the value with the mask bit 16
clear and then intel_init_thermal() would replicate it onto the APs and
all would be peachy - the thermal interrupt would remain enabled.

But that commit moved that reading to a later moment in
intel_init_thermal(), resulting in reading APIC_LVTTHMR on the BSP too
late and with its interrupt mask bit set.

Thus, revert back to the old behavior of reading the thermal LVT
register before the APIC gets initialized.

Fixes: 4f432e8bb1 ("x86/mce: Get rid of mcheck_intel_therm_init()")
Reported-by: James Feeney <james@nurealm.net>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://lkml.kernel.org/r/YKIqDdFNaXYd39wz@zn.tnic
2021-05-31 22:32:26 +02:00
Linus Torvalds 224478289c ARM fixes:
* Another state update on exit to userspace fix
 
 * Prevent the creation of mixed 32/64 VMs
 
 * Fix regression with irqbypass not restarting the guest on failed connect
 
 * Fix regression with debug register decoding resulting in overlapping access
 
 * Commit exception state on exit to usrspace
 
 * Fix the MMU notifier return values
 
 * Add missing 'static' qualifiers in the new host stage-2 code
 
 x86 fixes:
 * fix guest missed wakeup with assigned devices
 
 * fix WARN reported by syzkaller
 
 * do not use BIT() in UAPI headers
 
 * make the kvm_amd.avic parameter bool
 
 PPC fixes:
 * make halt polling heuristics consistent with other architectures
 
 selftests:
 * various fixes
 
 * new performance selftest memslot_perf_test
 
 * test UFFD minor faults in demand_paging_test
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "ARM fixes:

   - Another state update on exit to userspace fix

   - Prevent the creation of mixed 32/64 VMs

   - Fix regression with irqbypass not restarting the guest on failed
     connect

   - Fix regression with debug register decoding resulting in
     overlapping access

   - Commit exception state on exit to usrspace

   - Fix the MMU notifier return values

   - Add missing 'static' qualifiers in the new host stage-2 code

  x86 fixes:

   - fix guest missed wakeup with assigned devices

   - fix WARN reported by syzkaller

   - do not use BIT() in UAPI headers

   - make the kvm_amd.avic parameter bool

  PPC fixes:

   - make halt polling heuristics consistent with other architectures

  selftests:

   - various fixes

   - new performance selftest memslot_perf_test

   - test UFFD minor faults in demand_paging_test"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (44 commits)
  selftests: kvm: fix overlapping addresses in memslot_perf_test
  KVM: X86: Kill off ctxt->ud
  KVM: X86: Fix warning caused by stale emulation context
  KVM: X86: Use kvm_get_linear_rip() in single-step and #DB/#BP interception
  KVM: x86/mmu: Fix comment mentioning skip_4k
  KVM: VMX: update vcpu posted-interrupt descriptor when assigning device
  KVM: rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK
  KVM: x86: add start_assignment hook to kvm_x86_ops
  KVM: LAPIC: Narrow the timer latency between wait_lapic_expire and world switch
  selftests: kvm: do only 1 memslot_perf_test run by default
  KVM: X86: Use _BITUL() macro in UAPI headers
  KVM: selftests: add shared hugetlbfs backing source type
  KVM: selftests: allow using UFFD minor faults for demand paging
  KVM: selftests: create alias mappings when using shared memory
  KVM: selftests: add shmem backing source type
  KVM: selftests: refactor vm_mem_backing_src_type flags
  KVM: selftests: allow different backing source types
  KVM: selftests: compute correct demand paging size
  KVM: selftests: simplify setup_demand_paging error handling
  KVM: selftests: Print a message if /dev/kvm is missing
  ...
2021-05-29 06:02:25 -10:00
Thomas Gleixner 7d65f9e806 x86/apic: Mark _all_ legacy interrupts when IO/APIC is missing
PIC interrupts do not support affinity setting and they can end up on
any online CPU. Therefore, it's required to mark the associated vectors
as system-wide reserved. Otherwise, the corresponding irq descriptors
are copied to the secondary CPUs but the vectors are not marked as
assigned or reserved. This works correctly for the IO/APIC case.

When the IO/APIC is disabled via config, kernel command line or lack of
enumeration then all legacy interrupts are routed through the PIC, but
nothing marks them as system-wide reserved vectors.

As a consequence, a subsequent allocation on a secondary CPU can result in
allocating one of these vectors, which triggers the BUG() in
apic_update_vector() because the interrupt descriptor slot is not empty.

Imran tried to work around that by marking those interrupts as allocated
when a CPU comes online. But that's wrong in case that the IO/APIC is
available and one of the legacy interrupts, e.g. IRQ0, has been switched to
PIC mode because then marking them as allocated will fail as they are
already marked as system vectors.

Stay consistent and update the legacy vectors after attempting IO/APIC
initialization and mark them as system vectors in case that no IO/APIC is
available.

Fixes: 69cde0004a ("x86/vector: Use matrix allocator for vector assignment")
Reported-by: Imran Khan <imran.f.khan@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210519233928.2157496-1-imran.f.khan@oracle.com
2021-05-29 11:41:14 +02:00
Muralidhara M K 94a311ce24 x86/MCE/AMD, EDAC/mce_amd: Add new SMCA bank types
Add the (HWID, MCATYPE) tuples and names for new SMCA bank types.

Also, add their respective error descriptions to the MCE decoding module
edac_mce_amd. Also while at it, optimize the string names for some SMCA
banks.

 [ bp: Drop repeated comments, explain why UMC_V2 is a separate entry. ]

Signed-off-by: Muralidhara M K <muralimk@amd.com>
Signed-off-by: Naveen Krishna Chatradhi  <nchatrad@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lkml.kernel.org/r/20210526164601.66228-1-nchatrad@amd.com
2021-05-27 20:08:14 +02:00
Marcelo Tosatti 57ab87947a KVM: x86: add start_assignment hook to kvm_x86_ops
Add a start_assignment hook to kvm_x86_ops, which is called when
kvm_arch_start_assignment is done.

The hook is required to update the wakeup vector of a sleeping vCPU
when a device is assigned to the guest.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Message-Id: <20210525134321.254128742@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-27 07:50:13 -04:00
Mark Rutland 9be85de977 locking/atomic: make ARCH_ATOMIC a Kconfig symbol
Subsequent patches will move architectures over to the ARCH_ATOMIC API,
after preparing the asm-generic atomic implementations to function with
or without ARCH_ATOMIC.

As some architectures use the asm-generic implementations exclusively
(and don't have a local atomic.h), and to avoid the risk that
ARCH_ATOMIC isn't defined in some cases we expect, let's make the
ARCH_ATOMIC macro a Kconfig symbol instead, so that we can guarantee it
is consistently available where needed.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210525140232.53872-2-mark.rutland@arm.com
2021-05-26 13:20:49 +02:00
H. Peter Anvin (Intel) 2978996f62 x86/entry: Use int everywhere for system call numbers
System call numbers are defined as int, so use int everywhere for system
call numbers. This is strictly a cleanup; it should not change anything
user visible; all ABI changes have been done in the preceeding patches.

[ tglx: Replaced the unsigned long cast ]

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210518191303.4135296-7-hpa@zytor.com
2021-05-25 10:07:00 +02:00
H. Peter Anvin (Intel) 283fa3b648 x86: Add native_[ig]dt_invalidate()
In some places, the native forms of descriptor table invalidation is
required. Rather than open-coding them, add explicitly native functions to
invalidate the GDT and IDT.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210519212154.511983-6-hpa@zytor.com
2021-05-21 12:36:45 +02:00
H. Peter Anvin (Intel) 8ec9069a43 x86/idt: Remove address argument from idt_invalidate()
There is no reason to specify any specific address to idt_invalidate(). It
looks mostly like an artifact of unifying code done differently by
accident. The most "sensible" address to set here is a NULL pointer -
virtual address zero, just as a visual marker.

This also makes it possible to mark the struct desc_ptr in idt_invalidate()
as static const.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210519212154.511983-5-hpa@zytor.com
2021-05-21 12:36:45 +02:00
H. Peter Anvin (Intel) ff85100388 x86/irq: Add and use NR_EXTERNAL_VECTORS and NR_SYSTEM_VECTORS
Add defines for the number of external vectors and number of system
vectors instead of requiring the use of (FIRST_SYSTEM_VECTOR -
FIRST_EXTERNAL_VECTOR) and (NR_VECTORS - FIRST_SYSTEM_VECTOR)
respectively. Clean up the usage sites.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20210519212154.511983-3-hpa@zytor.com
2021-05-21 12:36:44 +02:00
H. Peter Anvin (Intel) f1b7d45d3f x86/irq: Remove unused vectors defines
UV_BAU_MESSAGE is defined but not used anywhere in the kernel. Presumably
this is a stale vector number that can be reclaimed.

MCE_VECTOR is not an actual vector: #MC is an exception, not an interrupt
vector, and as such is correctly described as X86_TRAP_MC. MCE_VECTOR is
not used anywhere is the kernel.

Note that NMI_VECTOR *is* used; specifically it is the vector number
programmed into the APIC LVT when an NMI interrupt is configured. At
the moment it is always numerically identical to X86_TRAP_NMI, that is
not necessarily going to be the case indefinitely.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lore.kernel.org/r/20210519212154.511983-4-hpa@zytor.com
2021-05-21 12:36:44 +02:00
Joe Richey d06aca989c x86/elf: Use _BITUL() macro in UAPI headers
Replace BIT() in x86's UAPI header with _BITUL(). BIT() is not defined
in the UAPI headers and its usage may cause userspace build errors.

Fixes: 742c45c3ec ("x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2")
Signed-off-by: Joe Richey <joerichey@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210521085849.37676-2-joerichey94@gmail.com
2021-05-21 11:12:52 +02:00
Masahiro Yamada 49f731f197 x86/syscalls: Use __NR_syscalls instead of __NR_syscall_max
__NR_syscall_max is only used by x86 and UML. In contrast, __NR_syscalls is
widely used by all the architectures.

Convert __NR_syscall_max to __NR_syscalls and adjust the usage sites.

This prepares x86 to switch to the generic syscallhdr.sh script.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210517073815.97426-6-masahiroy@kernel.org
2021-05-20 15:03:59 +02:00
Masahiro Yamada f63815eb1d x86/unistd: Define X32_NR_syscalls only for 64-bit kernel
X32_NR_syscalls is needed only when building a 64bit kernel.

Move it to proper #ifdef guard.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210517073815.97426-5-masahiroy@kernel.org
2021-05-20 15:03:59 +02:00
Masahiro Yamada 6218d0f6b8 x86/syscalls: Switch to generic syscalltbl.sh
Many architectures duplicate similar shell scripts.

Convert x86 and UML to use scripts/syscalltbl.sh. The generic script
generates seperate headers for x86/64 and x86/x32 syscalls, while the x86
specific script coalesced them into one. Adjust the code accordingly.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210517073815.97426-3-masahiroy@kernel.org
2021-05-20 15:03:58 +02:00
Masahiro Yamada 2e958a8a51 x86/entry/x32: Rename __x32_compat_sys_* to __x64_compat_sys_*
The SYSCALL macros are mapped to symbols as follows:

  __SYSCALL_COMMON(nr, sym)  -->  __x64_<sym>
  __SYSCALL_X32(nr, sym)     -->  __x32_<sym>

Originally, the syscalls in the x32 special range (512-547) were all
compat.

This assumption is now broken after the following commits:

  55db9c0e85 ("net: remove compat_sys_{get,set}sockopt")
  5f764d624a ("fs: remove the compat readv/writev syscalls")
  598b3cec83 ("fs: remove compat_sys_vmsplice")
  c3973b401e ("mm: remove compat_process_vm_{readv,writev}")

Those commits redefined __x32_sys_* to __x64_sys_* because there is no stub
like __x32_sys_*.

Defining them as follows is more sensible and cleaner.

  __SYSCALL_COMMON(nr, sym)  -->  __x64_<sym>
  __SYSCALL_X32(nr, sym)     -->  __x64_<sym>

This works because both x86_64 and x32 use the same ABI (RDI, RSI, RDX,
R10, R8, R9)

The ugly #define __x32_sys_* will go away.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210517073815.97426-2-masahiroy@kernel.org
2021-05-20 15:03:58 +02:00
Chang S. Bae 1c33bb0507 x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ
Historically, signal.h defines MINSIGSTKSZ (2KB) and SIGSTKSZ (8KB), for
use by all architectures with sigaltstack(2). Over time, the hardware state
size grew, but these constants did not evolve. Today, literal use of these
constants on several architectures may result in signal stack overflow, and
thus user data corruption.

A few years ago, the ARM team addressed this issue by establishing
getauxval(AT_MINSIGSTKSZ). This enables the kernel to supply a value
at runtime that is an appropriate replacement on current and future
hardware.

Add getauxval(AT_MINSIGSTKSZ) support to x86, analogous to the support
added for ARM in

  94b07c1f8c ("arm64: signal: Report signal frame size to userspace via auxv").

Also, include a documentation to describe x86-specific auxiliary vectors.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20210518200320.17239-4-chang.seok.bae@intel.com
2021-05-19 12:18:45 +02:00
Chang S. Bae 939ef71329 x86/signal: Introduce helpers to get the maximum signal frame size
Signal frames do not have a fixed format and can vary in size when a number
of things change: supported XSAVE features, 32 vs. 64-bit apps, etc.

Add support for a runtime method for userspace to dynamically discover
how large a signal stack needs to be.

Introduce a new variable, max_frame_size, and helper functions for the
calculation to be used in a new user interface. Set max_frame_size to a
system-wide worst-case value, instead of storing multiple app-specific
values.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H.J. Lu <hjl.tools@gmail.com>
Link: https://lkml.kernel.org/r/20210518200320.17239-3-chang.seok.bae@intel.com
2021-05-19 11:46:27 +02:00
Thomas Gleixner 1dcc917a0e x86/idt: Rework IDT setup for boot CPU
A basic IDT setup for the boot CPU has to be done before invoking
cpu_init() because that might trigger #GP when accessing certain MSRs. This
setup cannot install the IST variants on 64-bit because the TSS setup which
is required for ISTs to work happens in cpu_init(). That leaves a
theoretical window where a NMI would invoke the ASM entry point which
relies on IST being enabled on the kernel stack which is undefined
behaviour.

This setup logic has never worked correctly, but on the other hand a NMI
hitting the boot CPU before it has fully set up the IDT would be fatal
anyway. So the small window between the wrong NMI gate and the IST based
NMI gate is not really adding a substantial amount of risk.

But the setup logic is nevertheless more convoluted than necessary. The
recent separation of the TSS setup into a separate function to ensure that
setup so it can setup TSS first, then initialize IDT with the IST variants
before invoking cpu_init() and get rid of the post cpu_init() IST setup.

Move the invocation of cpu_init_exception_handling() ahead of
idt_setup_traps() and merge the IST setup into the default setup table.

Reported-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lai Jiangshan <laijs@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210507114000.569244755@linutronix.de
2021-05-18 14:49:21 +02:00
Borislav Petkov b1efd0ff4b x86/cpu: Init AP exception handling from cpu_init_secondary()
SEV-ES guests require properly setup task register with which the TSS
descriptor in the GDT can be located so that the IST-type #VC exception
handler which they need to function properly, can be executed.

This setup needs to happen before attempting to load microcode in
ucode_cpu_init() on secondary CPUs which can cause such #VC exceptions.

Simplify the machinery by running that exception setup from a new function
cpu_init_secondary() and explicitly call cpu_init_exception_handling() for
the boot CPU before cpu_init(). The latter prepares for fixing and
simplifying the exception/IST setup on the boot CPU.

There should be no functional changes resulting from this patch.

[ tglx: Reworked it so cpu_init_exception_handling() stays seperate ]

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lai Jiangshan <laijs@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>                                                                                                                                                                                                                        
Link: https://lore.kernel.org/r/87k0o6gtvu.ffs@nanos.tec.linutronix.de
2021-05-18 14:49:21 +02:00
Paolo Bonzini a4345a7cec KVM/arm64 fixes for 5.13, take #1
- Fix regression with irqbypass not restarting the guest on failed connect
 - Fix regression with debug register decoding resulting in overlapping access
 - Commit exception state on exit to usrspace
 - Fix the MMU notifier return values
 - Add missing 'static' qualifiers in the new host stage-2 code
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Merge tag 'kvmarm-fixes-5.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 5.13, take #1

- Fix regression with irqbypass not restarting the guest on failed connect
- Fix regression with debug register decoding resulting in overlapping access
- Commit exception state on exit to usrspace
- Fix the MMU notifier return values
- Add missing 'static' qualifiers in the new host stage-2 code
2021-05-17 09:55:12 +02:00
Linus Torvalds 8ce3648158 Two fixes for timers:
- Use the ALARM feature check in the alarmtimer core code insted of
     the old method of checking for the set_alarm() callback. Drivers
     can have that callback set but the feature bit cleared. If such
     a RTC device is selected then alarms wont work.
 
   - Use a proper define to let the preprocessor check whether Hyper-V VDSO
     clocksource should be active. The code used a constant in an enum with
     #ifdef, which evaluates to always false and disabled the clocksource
     for VDSO.
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Merge tag 'timers-urgent-2021-05-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fixes from Thomas Gleixner:
 "Two fixes for timers:

   - Use the ALARM feature check in the alarmtimer core code insted of
     the old method of checking for the set_alarm() callback.

     Drivers can have that callback set but the feature bit cleared. If
     such a RTC device is selected then alarms wont work.

   - Use a proper define to let the preprocessor check whether Hyper-V
     VDSO clocksource should be active.

     The code used a constant in an enum with #ifdef, which evaluates to
     always false and disabled the clocksource for VDSO"

* tag 'timers-urgent-2021-05-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/hyper-v: Re-enable VDSO_CLOCKMODE_HVCLOCK on X86
  alarmtimer: Check RTC features instead of ops
2021-05-16 09:42:13 -07:00
Linus Torvalds ccb013c29d - Enable -Wundef for the compressed kernel build stage
- Reorganize SEV code to streamline and simplify future development
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Merge tag 'x86_urgent_for_v5.13_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:
 "The three SEV commits are not really urgent material. But we figured
  since getting them in now will avoid a huge amount of conflicts
  between future SEV changes touching tip, the kvm and probably other
  trees, sending them to you now would be best.

  The idea is that the tip, kvm etc branches for 5.14 will all base
  ontop of -rc2 and thus everything will be peachy. What is more, those
  changes are purely mechanical and defines movement so they should be
  fine to go now (famous last words).

  Summary:

   - Enable -Wundef for the compressed kernel build stage

   - Reorganize SEV code to streamline and simplify future development"

* tag 'x86_urgent_for_v5.13_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot/compressed: Enable -Wundef
  x86/msr: Rename MSR_K8_SYSCFG to MSR_AMD64_SYSCFG
  x86/sev: Move GHCB MSR protocol and NAE definitions in a common header
  x86/sev-es: Rename sev-es.{ch} to sev.{ch}
2021-05-16 09:31:06 -07:00
Vitaly Kuznetsov 3486d2c9be clocksource/drivers/hyper-v: Re-enable VDSO_CLOCKMODE_HVCLOCK on X86
Mohammed reports (https://bugzilla.kernel.org/show_bug.cgi?id=213029)
the commit e4ab4658f1 ("clocksource/drivers/hyper-v: Handle vDSO
differences inline") broke vDSO on x86. The problem appears to be that
VDSO_CLOCKMODE_HVCLOCK is an enum value in 'enum vdso_clock_mode' and
'#ifdef VDSO_CLOCKMODE_HVCLOCK' branch evaluates to false (it is not
a define).

Use a dedicated HAVE_VDSO_CLOCKMODE_HVCLOCK define instead.

Fixes: e4ab4658f1 ("clocksource/drivers/hyper-v: Handle vDSO differences inline")
Reported-by: Mohammed Gamal <mgamal@redhat.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210513073246.1715070-1-vkuznets@redhat.com
2021-05-14 14:55:13 +02:00
Andi Kleen 28188cc461 x86/cpu: Fix core name for Sapphire Rapids
Sapphire Rapids uses Golden Cove, not Willow Cove.

Fixes: 53375a5a21 ("x86/cpu: Resort and comment Intel models")
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210513163904.3083274-1-ak@linux.intel.com
2021-05-14 14:31:14 +02:00
Ingo Molnar 41f45fb045 x86/asm: Make <asm/asm.h> valid on cross-builds as well
Stephen Rothwell reported that the objtool cross-build breaks on
non-x86 hosts:

  > tools/arch/x86/include/asm/asm.h:185:24: error: invalid register name for 'current_stack_pointer'
  >   185 | register unsigned long current_stack_pointer asm(_ASM_SP);
  >       |                        ^~~~~~~~~~~~~~~~~~~~~

The PowerPC host obviously doesn't know much about x86 register names.

Protect the kernel-specific bits of <asm/asm.h>, so that it can be
included by tooling and cross-built.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-05-14 08:50:28 +02:00
Huang Rui 3743d55b28 x86, sched: Fix the AMD CPPC maximum performance value on certain AMD Ryzen generations
Some AMD Ryzen generations has different calculation method on maximum
performance. 255 is not for all ASICs, some specific generations should use 166
as the maximum performance. Otherwise, it will report incorrect frequency value
like below:

  ~ → lscpu | grep MHz
  CPU MHz:                         3400.000
  CPU max MHz:                     7228.3198
  CPU min MHz:                     2200.0000

[ mingo: Tidied up whitespace use. ]
[ Alexander Monakov <amonakov@ispras.ru>: fix 225 -> 255 typo. ]

Fixes: 41ea667227 ("x86, sched: Calculate frequency invariance for AMD systems")
Fixes: 3c55e94c0a ("cpufreq: ACPI: Extend frequency tables to cover boost frequencies")
Reported-by: Jason Bagavatsingham <jason.bagavatsingham@gmail.com>
Fixed-by: Alexander Monakov <amonakov@ispras.ru>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Jason Bagavatsingham <jason.bagavatsingham@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210425073451.2557394-1-ray.huang@amd.com
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211791
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-05-13 12:10:24 +02:00
Ingo Molnar c43426334b x86: Fix leftover comment typos
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-05-12 20:00:51 +02:00
Ingo Molnar 6f0d271d21 Merge branch 'linus' into x86/cleanups, to pick up dependent commits
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-05-12 19:59:37 +02:00
Peter Zijlstra ab3257042c jump_label, x86: Allow short NOPs
Now that objtool is able to rewrite jump_label instructions, have the
compiler emit a JMP, such that it can decide on the optimal encoding,
and set jump_entry::key bit1 to indicate that objtool should rewrite
the instruction to a matching NOP.

For x86_64-allyesconfig this gives:

  jl\     NOP     JMP
  short:  22997   124
  long:   30874   90

IOW, we save (22997+124) * 3 bytes of kernel text in hotpaths.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194158.216763632@infradead.org
2021-05-12 14:54:56 +02:00
Peter Zijlstra e7bf1ba97a jump_label, x86: Emit short JMP
Now that we can patch short JMP/NOP, allow the compiler/assembler to
emit short JMP instructions.

There is no way to have the assembler emit short NOPs based on the
potential displacement, so leave those long for now.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194157.967034497@infradead.org
2021-05-12 14:54:55 +02:00
Peter Zijlstra fa5e5dc396 jump_label, x86: Introduce jump_entry_size()
This allows architectures to have variable sized jumps.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194157.786777050@infradead.org
2021-05-12 14:54:55 +02:00
Peter Zijlstra e1aa35c4c4 jump_label, x86: Factor out the __jump_table generation
Both arch_static_branch() and arch_static_branch_jump() have the same
blurb to generate the __jump_table entry, share it.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194157.663132781@infradead.org
2021-05-12 14:54:55 +02:00