Commit Graph

35799 Commits

Author SHA1 Message Date
Juergen Gross a13f2ef168 x86/xen: remove 32-bit Xen PV guest support
Xen is requiring 64-bit machines today and since Xen 4.14 it can be
built without 32-bit PV guest support. There is no need to carry the
burden of 32-bit PV guest support in the kernel any longer, as new
guests can be either HVM or PVH, or they can use a 64 bit kernel.

Remove the 32-bit Xen PV support from the kernel.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
2020-08-11 08:26:48 +02:00
Randy Dunlap 4e722d4fe2 xen: hypercall.h: fix duplicated word
Change the repeated word "as" to "as a".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: xen-devel@lists.xenproject.org
Link: https://lore.kernel.org/r/20200726001731.19540-1-rdunlap@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
2020-08-03 07:48:39 +02:00
Linus Torvalds 5a30a78924 A single fix for a potential deadlock when printing a message about spurious interrupts.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2020-08-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fix from Ingo Molnar:
 "A single fix for a potential deadlock when printing a message about
  spurious interrupts"

* tag 'x86-urgent-2020-08-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/i8259: Use printk_deferred() to prevent deadlock
2020-08-02 13:10:42 -07:00
Linus Torvalds 628e04dfeb Bugfixes and strengthening the validity checks on inputs from new userspace APIs.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "Bugfixes and strengthening the validity checks on inputs from new
  userspace APIs.

  Now I know why I shouldn't prepare pull requests on the weekend, it's
  hard to concentrate if your son is shouting about his latest Minecraft
  builds in your ear. Fortunately all the patches were ready and I just
  had to check the test results..."

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: SVM: Fix disable pause loop exit/pause filtering capability on SVM
  KVM: LAPIC: Prevent setting the tscdeadline timer if the lapic is hw disabled
  KVM: arm64: Don't inherit exec permission across page-table levels
  KVM: arm64: Prevent vcpu_has_ptrauth from generating OOL functions
  KVM: nVMX: check for invalid hdr.vmx.flags
  KVM: nVMX: check for required but missing VMCS12 in KVM_SET_NESTED_STATE
  selftests: kvm: do not set guest mode flag
2020-08-02 10:41:00 -07:00
Wanpeng Li 830f01b089 KVM: SVM: Fix disable pause loop exit/pause filtering capability on SVM
'Commit 8566ac8b8e ("KVM: SVM: Implement pause loop exit logic in SVM")'
drops disable pause loop exit/pause filtering capability completely, I
guess it is a merge fault by Radim since disable vmexits capabilities and
pause loop exit for SVM patchsets are merged at the same time. This patch
reintroduces the disable pause loop exit/pause filtering capability support.

Reported-by: Haiwei Li <lihaiwei@tencent.com>
Tested-by: Haiwei Li <lihaiwei@tencent.com>
Fixes: 8566ac8b ("KVM: SVM: Implement pause loop exit logic in SVM")
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1596165141-28874-3-git-send-email-wanpengli@tencent.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-31 03:20:32 -04:00
Wanpeng Li d2286ba7d5 KVM: LAPIC: Prevent setting the tscdeadline timer if the lapic is hw disabled
Prevent setting the tscdeadline timer if the lapic is hw disabled.

Fixes: bce87cce88 (KVM: x86: consolidate different ways to test for in-kernel LAPIC)
Cc: <stable@vger.kernel.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1596165141-28874-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-31 03:20:15 -04:00
Thomas Gleixner bdd6558959 x86/i8259: Use printk_deferred() to prevent deadlock
0day reported a possible circular locking dependency:

Chain exists of:
  &irq_desc_lock_class --> console_owner --> &port_lock_key

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&port_lock_key);
                               lock(console_owner);
                               lock(&port_lock_key);
  lock(&irq_desc_lock_class);

The reason for this is a printk() in the i8259 interrupt chip driver
which is invoked with the irq descriptor lock held, which reverses the
lock operations vs. printk() from arbitrary contexts.

Switch the printk() to printk_deferred() to avoid that.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87365abt2v.fsf@nanos.tec.linutronix.de
2020-07-29 16:27:16 +02:00
Paolo Bonzini 5e105c88ab KVM: nVMX: check for invalid hdr.vmx.flags
hdr.vmx.flags is meant for future extensions to the ABI, rejecting
invalid flags is necessary to avoid broken half-loads of the
nVMX state.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-27 09:04:50 -04:00
Paolo Bonzini 0f02bd0ade KVM: nVMX: check for required but missing VMCS12 in KVM_SET_NESTED_STATE
A missing VMCS12 was not causing -EINVAL (it was just read with
copy_from_user, so it is not a security issue, but it is still
wrong).  Test for VMCS12 validity and reject the nested state
if a VMCS12 is required but not present.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-27 09:04:49 -04:00
Linus Torvalds fbe0d451bc Misc fixes:
- Fix a section end page alignment assumption that was causing crashes
 
  - Fix ORC unwinding on freshly forked tasks which haven't executed yet
    and which have empty user task stacks
 
  - Fix the debug.exception-trace=1 sysctl dumping of user stacks, which
    was broken by recent maccess changes
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull x86 fixes from Ingo Molnar:
 "Misc fixes:

   - Fix a section end page alignment assumption that was causing
     crashes

   - Fix ORC unwinding on freshly forked tasks which haven't executed
     yet and which have empty user task stacks

   - Fix the debug.exception-trace=1 sysctl dumping of user stacks,
     which was broken by recent maccess changes"

* tag 'x86-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/dumpstack: Dump user space code correctly again
  x86/stacktrace: Fix reliable check for empty user task stacks
  x86/unwind/orc: Fix ORC for newly forked tasks
  x86, vmlinux.lds: Page-align end of ..page_aligned sections
2020-07-25 14:25:47 -07:00
Thomas Gleixner d181d2da01 x86/dumpstack: Dump user space code correctly again
H.J. reported that post 5.7 a segfault of a user space task does not longer
dump the Code bytes when /proc/sys/debug/exception-trace is enabled. It
prints 'Code: Bad RIP value.' instead.

This was broken by a recent change which made probe_kernel_read() reject
non-kernel addresses.

Update show_opcodes() so it retrieves user space opcodes via
copy_from_user_nmi().

Fixes: 98a23609b1 ("maccess: always use strict semantics for probe_kernel_read")
Reported-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/87h7tz306w.fsf@nanos.tec.linutronix.de
2020-07-22 23:47:48 +02:00
Josh Poimboeuf 039a7a30ec x86/stacktrace: Fix reliable check for empty user task stacks
If a user task's stack is empty, or if it only has user regs, ORC
reports it as a reliable empty stack.  But arch_stack_walk_reliable()
incorrectly treats it as unreliable.

That happens because the only success path for user tasks is inside the
loop, which only iterates on non-empty stacks.  Generally, a user task
must end in a user regs frame, but an empty stack is an exception to
that rule.

Thanks to commit 71c9582528 ("x86/unwind/orc: Fix error handling in
__unwind_start()"), unwind_start() now sets state->error appropriately.
So now for both ORC and FP unwinders, unwind_done() and !unwind_error()
always means the end of the stack was successfully reached.  So the
success path for kthreads is no longer needed -- it can also be used for
empty user tasks.

Reported-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Link: https://lkml.kernel.org/r/f136a4e5f019219cbc4f4da33b30c2f44fa65b84.1594994374.git.jpoimboe@redhat.com
2020-07-22 23:47:47 +02:00
Josh Poimboeuf 372a8eaa05 x86/unwind/orc: Fix ORC for newly forked tasks
The ORC unwinder fails to unwind newly forked tasks which haven't yet
run on the CPU.  It correctly reads the 'ret_from_fork' instruction
pointer from the stack, but it incorrectly interprets that value as a
call stack address rather than a "signal" one, so the address gets
incorrectly decremented in the call to orc_find(), resulting in bad ORC
data.

Fix it by forcing 'ret_from_fork' frames to be signal frames.

Reported-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Link: https://lkml.kernel.org/r/f91a8778dde8aae7f71884b5df2b16d552040441.1594994374.git.jpoimboe@redhat.com
2020-07-22 23:47:47 +02:00
Linus Torvalds d15be54603 media fixes for v5.8-rc7
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Merge tag 'media/v5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media into master

Pull media fixes from Mauro Carvalho Chehab:
 "A series of fixes for the upcoming atomisp driver. They solve issues
  when probing atomisp on devices with multiple cameras and get rid of
  warnings when built with W=1.

  The diffstat is a bit long, as this driver has several abstractions.
  The patches that solved the issues with W=1 had to get rid of some
  duplicated code (there used to have 2 versions of the same code, one
  for ISP2401 and another one for ISP2400).

  As this driver is not in 5.7, such changes won't cause regressions"

* tag 'media/v5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (38 commits)
  Revert "media: atomisp: keep the ISP powered on when setting it"
  media: atomisp: fix mask and shift operation on ISPSSPM0
  media: atomisp: move system_local consts into a C file
  media: atomisp: get rid of version-specific system_local.h
  media: atomisp: move global stuff into a common header
  media: atomisp: remove non-used 32-bits consts at system_local
  media: atomisp: get rid of some unused static vars
  media: atomisp: Fix error code in ov5693_probe()
  media: atomisp: Replace trace_printk by pr_info
  media: atomisp: Fix __func__ style warnings
  media: atomisp: fix help message for ISP2401 selection
  media: atomisp: i2c: atomisp-ov2680.c: fixed a brace coding style issue.
  media: atomisp: make const arrays static, makes object smaller
  media: atomisp: Clean up non-existing folders from Makefile
  media: atomisp: Get rid of ACPI specifics in gmin_subdev_add()
  media: atomisp: Provide Gmin subdev as parameter to gmin_subdev_add()
  media: atomisp: Use temporary variable for device in gmin_subdev_add()
  media: atomisp: Refactor PMIC detection to a separate function
  media: atomisp: Deduplicate return ret in gmin_i2c_write()
  media: atomisp: Make pointer to PMIC client global
  ...
2020-07-22 11:56:00 -07:00
Joerg Roedel de2b41be8f x86, vmlinux.lds: Page-align end of ..page_aligned sections
On x86-32 the idt_table with 256 entries needs only 2048 bytes. It is
page-aligned, but the end of the .bss..page_aligned section is not
guaranteed to be page-aligned.

As a result, objects from other .bss sections may end up on the same 4k
page as the idt_table, and will accidentially get mapped read-only during
boot, causing unexpected page-faults when the kernel writes to them.

This could be worked around by making the objects in the page aligned
sections page sized, but that's wrong.

Explicit sections which store only page aligned objects have an implicit
guarantee that the object is alone in the page in which it is placed. That
works for all objects except the last one. That's inconsistent.

Enforcing page sized objects for these sections would wreckage memory
sanitizers, because the object becomes artificially larger than it should
be and out of bound access becomes legit.

Align the end of the .bss..page_aligned and .data..page_aligned section on
page-size so all objects places in these sections are guaranteed to have
their own page.

[ tglx: Amended changelog ]

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200721093448.10417-1-joro@8bytes.org
2020-07-22 09:38:37 +02:00
Kevin Buettner 5714ee50bb copy_xstate_to_kernel: Fix typo which caused GDB regression
This fixes a regression encountered while running the
gdb.base/corefile.exp test in GDB's test suite.

In my testing, the typo prevented the sw_reserved field of struct
fxregs_state from being output to the kernel XSAVES area.  Thus the
correct mask corresponding to XCR0 was not present in the core file for
GDB to interrogate, resulting in the following behavior:

   [kev@f32-1 gdb]$ ./gdb -q testsuite/outputs/gdb.base/corefile/corefile testsuite/outputs/gdb.base/corefile/corefile.core
   Reading symbols from testsuite/outputs/gdb.base/corefile/corefile...
   [New LWP 232880]

   warning: Unexpected size of section `.reg-xstate/232880' in core file.

With the typo fixed, the test works again as expected.

Signed-off-by: Kevin Buettner <kevinb@redhat.com>
Fixes: 9e46365459 ("copy_xstate_to_kernel(): don't leave parts of destination uninitialized")
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Airlie <airlied@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-19 17:09:10 -07:00
Linus Torvalds efb9666e90 A pile of fixes for x86:
- Fix the I/O bitmap invalidation on XEN PV, which was overlooked in the
    recent ioperm/iopl rework. This caused the TSS and XEN's I/O bitmap to
    get out of sync.
 
  - Use the proper vectors for HYPERV.
 
  - Make disabling of stack protector for the entry code work with GCC
    builds which enable stack protector by default. Removing the option is
    not sufficient, it needs an explicit -fno-stack-protector to shut it
    off.
 
  - Mark check_user_regs() noinstr as it is called from noinstr code. The
    missing annotation causes it to be placed in the text section which
    makes it instrumentable.
 
  - Add the missing interrupt disable in exc_alignment_check()
 
  - Fixup a XEN_PV build dependency in the 32bit entry code
 
  - A few fixes to make the Clang integrated assembler happy
 
  - Move EFI stub build to the right place for out of tree builds
 
  - Make prepare_exit_to_usermode() static. It's not longer called from ASM
    code.
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Merge tag 'x86-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull x86 fixes from Thomas Gleixner:
 "A pile of fixes for x86:

   - Fix the I/O bitmap invalidation on XEN PV, which was overlooked in
     the recent ioperm/iopl rework. This caused the TSS and XEN's I/O
     bitmap to get out of sync.

   - Use the proper vectors for HYPERV.

   - Make disabling of stack protector for the entry code work with GCC
     builds which enable stack protector by default. Removing the option
     is not sufficient, it needs an explicit -fno-stack-protector to
     shut it off.

   - Mark check_user_regs() noinstr as it is called from noinstr code.
     The missing annotation causes it to be placed in the text section
     which makes it instrumentable.

   - Add the missing interrupt disable in exc_alignment_check()

   - Fixup a XEN_PV build dependency in the 32bit entry code

   - A few fixes to make the Clang integrated assembler happy

   - Move EFI stub build to the right place for out of tree builds

   - Make prepare_exit_to_usermode() static. It's not longer called from
     ASM code"

* tag 'x86-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Don't add the EFI stub to targets
  x86/entry: Actually disable stack protector
  x86/ioperm: Fix io bitmap invalidation on Xen PV
  x86: math-emu: Fix up 'cmp' insn for clang ias
  x86/entry: Fix vectors to IDTENTRY_SYSVEC for CONFIG_HYPERV
  x86/entry: Add compatibility with IAS
  x86/entry/common: Make prepare_exit_to_usermode() static
  x86/entry: Mark check_user_regs() noinstr
  x86/traps: Disable interrupts in exc_aligment_check()
  x86/entry/32: Fix XEN_PV build dependency
2020-07-19 12:16:09 -07:00
Linus Torvalds 9413cd7792 Two fixes for the interrupt subsystem:
- Make the handling of the firmware node consistent and do not free the
    node after the domain has been created successfully. The core code
    stores a pointer to it which can lead to a use after free or double
    free.
 
    This used to "work" because the pointer was not stored when the initial
    code was written, but at some point later it was required to store
    it. Of course nobody noticed that the existing users break that way.
 
  - Handle affinity setting on inactive interrupts correctly when
    hierarchical irq domains are enabled. When interrupts are inactive with
    the modern hierarchical irqdomain design, the interrupt chips are not
    necessarily in a state where affinity changes can be handled. The legacy
    irq chip design allowed this because interrupts are immediately fully
    initialized at allocation time. X86 has a hacky workaround for this, but
    other implementations do not. This cased malfunction on GIC-V3. Instead
    of playing whack a mole to find all affected drivers, change the core
    code to store the requested affinity setting and then establish it when
    the interrupt is allocated, which makes the X86 hack go away.
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Merge tag 'irq-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull irq fixes from Thomas Gleixner:
 "Two fixes for the interrupt subsystem:

   - Make the handling of the firmware node consistent and do not free
     the node after the domain has been created successfully. The core
     code stores a pointer to it which can lead to a use after free or
     double free.

     This used to "work" because the pointer was not stored when the
     initial code was written, but at some point later it was required
     to store it. Of course nobody noticed that the existing users break
     that way.

   - Handle affinity setting on inactive interrupts correctly when
     hierarchical irq domains are enabled.

     When interrupts are inactive with the modern hierarchical irqdomain
     design, the interrupt chips are not necessarily in a state where
     affinity changes can be handled. The legacy irq chip design allowed
     this because interrupts are immediately fully initialized at
     allocation time. X86 has a hacky workaround for this, but other
     implementations do not.

     This cased malfunction on GIC-V3. Instead of playing whack a mole
     to find all affected drivers, change the core code to store the
     requested affinity setting and then establish it when the interrupt
     is allocated, which makes the X86 hack go away"

* tag 'irq-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/affinity: Handle affinity setting on inactive interrupts correctly
  irqdomain/treewide: Keep firmware node unconditionally allocated
2020-07-19 11:53:08 -07:00
Arvind Sankar da05b143a3 x86/boot: Don't add the EFI stub to targets
vmlinux-objs-y is added to targets, which currently means that the EFI
stub gets added to the targets as well. It shouldn't be added since it
is built elsewhere.

This confuses Makefile.build which interprets the EFI stub as a target
	$(obj)/$(objtree)/drivers/firmware/efi/libstub/lib.a
and will create drivers/firmware/efi/libstub/ underneath
arch/x86/boot/compressed, to hold this supposed target, if building
out-of-tree. [0]

Fix this by pulling the stub out of vmlinux-objs-y into efi-obj-y.

[0] See scripts/Makefile.build near the end:
    # Create directories for object files if they do not exist

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lkml.kernel.org/r/20200715032631.1562882-1-nivedita@alum.mit.edu
2020-07-19 13:07:11 +02:00
Kees Cook 58ac3154b8 x86/entry: Actually disable stack protector
Some builds of GCC enable stack protector by default. Simply removing
the arguments is not sufficient to disable stack protector, as the stack
protector for those GCC builds must be explicitly disabled. Remove the
argument removals and add -fno-stack-protector. Additionally include
missed x32 argument updates, and adjust whitespace for readability.

Fixes: 20355e5f73 ("x86/entry: Exclude low level entry code from sanitizing")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/202006261333.585319CA6B@keescook
2020-07-19 13:07:10 +02:00
Andy Lutomirski cadfad8701 x86/ioperm: Fix io bitmap invalidation on Xen PV
tss_invalidate_io_bitmap() wasn't wired up properly through the pvop
machinery, so the TSS and Xen's io bitmap would get out of sync
whenever disabling a valid io bitmap.

Add a new pvop for tss_invalidate_io_bitmap() to fix it.

This is XSA-329.

Fixes: 22fe5b0439 ("x86/ioperm: Move TSS bitmap update to exit to user work")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/d53075590e1f91c19f8af705059d3ff99424c020.1595030016.git.luto@kernel.org
2020-07-18 12:31:49 +02:00
Andy Shevchenko 5f55dd5499 media: atomisp: move CCK endpoint address to generic header
IOSF MBI header contains a lot of definitions, such as
end point addresses of IPs. Move CCK address from AtomISP driver
to generic header.

While here, drop unused one.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-07-18 07:17:16 +02:00
Thomas Gleixner baedb87d1b genirq/affinity: Handle affinity setting on inactive interrupts correctly
Setting interrupt affinity on inactive interrupts is inconsistent when
hierarchical irq domains are enabled. The core code should just store the
affinity and not call into the irq chip driver for inactive interrupts
because the chip drivers may not be in a state to handle such requests.

X86 has a hacky workaround for that but all other irq chips have not which
causes problems e.g. on GIC V3 ITS.

Instead of adding more ugly hacks all over the place, solve the problem in
the core code. If the affinity is set on an inactive interrupt then:

    - Store it in the irq descriptors affinity mask
    - Update the effective affinity to reflect that so user space has
      a consistent view
    - Don't call into the irq chip driver

This is the core equivalent of the X86 workaround and works correctly
because the affinity setting is established in the irq chip when the
interrupt is activated later on.

Note, that this is only effective when hierarchical irq domains are enabled
by the architecture. Doing it unconditionally would break legacy irq chip
implementations.

For hierarchial irq domains this works correctly as none of the drivers can
have a dependency on affinity setting in inactive state by design.

Remove the X86 workaround as it is not longer required.

Fixes: 02edee152d ("x86/apic/vector: Ignore set_affinity call for inactive interrupts")
Reported-by: Ali Saidi <alisaidi@amazon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ali Saidi <alisaidi@amazon.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200529015501.15771-1-alisaidi@amazon.com
Link: https://lkml.kernel.org/r/877dv2rv25.fsf@nanos.tec.linutronix.de
2020-07-17 23:30:43 +02:00
Arnd Bergmann 81e96851ea x86: math-emu: Fix up 'cmp' insn for clang ias
The clang integrated assembler requires the 'cmp' instruction to
have a length prefix here:

arch/x86/math-emu/wm_sqrt.S:212:2: error: ambiguous instructions require an explicit suffix (could be 'cmpb', 'cmpw', or 'cmpl')
 cmp $0xffffffff,-24(%ebp)
 ^

Make this a 32-bit comparison, which it was clearly meant to be.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lkml.kernel.org/r/20200527135352.1198078-1-arnd@arndb.de
2020-07-16 17:26:42 +02:00
Sedat Dilek 5769fe26f3 x86/entry: Fix vectors to IDTENTRY_SYSVEC for CONFIG_HYPERV
When assembling with Clang via `make LLVM_IAS=1` and CONFIG_HYPERV enabled,
we observe the following error:

<instantiation>:9:6: error: expected absolute expression
 .if HYPERVISOR_REENLIGHTENMENT_VECTOR == 3
     ^
<instantiation>:1:1: note: while in macro instantiation
idtentry HYPERVISOR_REENLIGHTENMENT_VECTOR asm_sysvec_hyperv_reenlightenment sysvec_hyperv_reenlightenment has_error_code=0
^
./arch/x86/include/asm/idtentry.h:627:1: note: while in macro instantiation
idtentry_sysvec HYPERVISOR_REENLIGHTENMENT_VECTOR sysvec_hyperv_reenlightenment;
^
<instantiation>:9:6: error: expected absolute expression
 .if HYPERVISOR_STIMER0_VECTOR == 3
     ^
<instantiation>:1:1: note: while in macro instantiation
idtentry HYPERVISOR_STIMER0_VECTOR asm_sysvec_hyperv_stimer0 sysvec_hyperv_stimer0 has_error_code=0
^
./arch/x86/include/asm/idtentry.h:628:1: note: while in macro instantiation
idtentry_sysvec HYPERVISOR_STIMER0_VECTOR sysvec_hyperv_stimer0;

This is caused by typos in arch/x86/include/asm/idtentry.h:

HYPERVISOR_REENLIGHTENMENT_VECTOR -> HYPERV_REENLIGHTENMENT_VECTOR
HYPERVISOR_STIMER0_VECTOR         -> HYPERV_STIMER0_VECTOR

For more details see ClangBuiltLinux issue #1088.

Fixes: a16be368dd ("x86/entry: Convert various hypervisor vectors to IDTENTRY_SYSVEC")
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1088
Link: https://github.com/ClangBuiltLinux/linux/issues/1043
Link: https://lore.kernel.org/patchwork/patch/1272115/
Link: https://lkml.kernel.org/r/20200714194740.4548-1-sedat.dilek@gmail.com
2020-07-16 17:25:10 +02:00
Jian Cai 6ee93f8df0 x86/entry: Add compatibility with IAS
Clang's integrated assembler does not allow symbols with non-absolute
values to be reassigned. Modify the interrupt entry loop macro to be
compatible with IAS by using a label and an offset.

Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Brian Gerst <brgerst@gmail.com>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Jian Cai <caij2003@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> #
Link: https://github.com/ClangBuiltLinux/linux/issues/1043
Link: https://lkml.kernel.org/r/20200714233024.1789985-1-caij2003@gmail.com
2020-07-16 17:25:09 +02:00
Thomas Gleixner e3beca48a4 irqdomain/treewide: Keep firmware node unconditionally allocated
Quite some non OF/ACPI users of irqdomains allocate firmware nodes of type
IRQCHIP_FWNODE_NAMED or IRQCHIP_FWNODE_NAMED_ID and free them right after
creating the irqdomain. The only purpose of these FW nodes is to convey
name information. When this was introduced the core code did not store the
pointer to the node in the irqdomain. A recent change stored the firmware
node pointer in irqdomain for other reasons and missed to notice that the
usage sites which do the alloc_fwnode/create_domain/free_fwnode sequence
are broken by this. Storing a dangling pointer is dangerous itself, but in
case that the domain is destroyed later on this leads to a double free.

Remove the freeing of the firmware node after creating the irqdomain from
all affected call sites to cure this.

Fixes: 711419e504 ("irqdomain: Add the missing assignment of domain->fwnode for named fwnode")
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/873661qakd.fsf@nanos.tec.linutronix.de
2020-07-14 17:44:42 +02:00
Linus Torvalds cb24c61b53 Two simple but important bugfixes.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull vkm fixes from Paolo Bonzini:
 "Two simple but important bugfixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: MIPS: Fix build errors for 32bit kernel
  KVM: nVMX: fixes for preemption timer migration
2020-07-10 08:34:12 -07:00
Paolo Bonzini 83d31e5271 KVM: nVMX: fixes for preemption timer migration
Commit 850448f35a ("KVM: nVMX: Fix VMX preemption timer migration",
2020-06-01) accidentally broke nVMX live migration from older version
by changing the userspace ABI.  Restore it and, while at it, ensure
that vmx->nested.has_preemption_timer_deadline is always initialized
according to the KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE flag.

Cc: Makarand Sonare <makarandsonare@google.com>
Fixes: 850448f35a ("KVM: nVMX: Fix VMX preemption timer migration")
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-10 06:15:36 -04:00
Thomas Gleixner bd87e6f661 x86/entry/common: Make prepare_exit_to_usermode() static
No users outside this file anymore.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200708192934.301116609@linutronix.de
2020-07-09 11:18:30 +02:00
Thomas Gleixner 006e1ced51 x86/entry: Mark check_user_regs() noinstr
It's called from the non-instrumentable section.

Fixes: c9c26150e6 ("x86/entry: Assert that syscalls are on the right stack")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200708192934.191497962@linutronix.de
2020-07-09 11:18:29 +02:00
Thomas Gleixner bce9b042ec x86/traps: Disable interrupts in exc_aligment_check()
exc_alignment_check() fails to disable interrupts before returning to the
entry code.

Fixes: ca4c6a9858 ("x86/traps: Make interrupt enable/disable symmetric in C code")
Reported-by: syzbot+0889df9502bc0f112b31@syzkaller.appspotmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200708192934.076519438@linutronix.de
2020-07-09 11:18:29 +02:00
Linus Torvalds bfe91da29b Bugfixes and a one-liner patch to silence sparse.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "Bugfixes and a one-liner patch to silence a sparse warning"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: arm64: Stop clobbering x0 for HVC_SOFT_RESTART
  KVM: arm64: PMU: Fix per-CPU access in preemptible context
  KVM: VMX: Use KVM_POSSIBLE_CR*_GUEST_BITS to initialize guest/host masks
  KVM: x86: Mark CR4.TSD as being possibly owned by the guest
  KVM: x86: Inject #GP if guest attempts to toggle CR4.LA57 in 64-bit mode
  kvm: use more precise cast and do not drop __user
  KVM: x86: bit 8 of non-leaf PDPEs is not reserved
  KVM: X86: Fix async pf caused null-ptr-deref
  KVM: arm64: vgic-v4: Plug race between non-residency and v4.1 doorbell
  KVM: arm64: pvtime: Ensure task delay accounting is enabled
  KVM: arm64: Fix kvm_reset_vcpu() return code being incorrect with SVE
  KVM: arm64: Annotate hyp NMI-related functions as __always_inline
  KVM: s390: reduce number of IO pins to 1
2020-07-06 12:48:04 -07:00
Linus Torvalds bb5a93aaf2 x86/ldt: use "pr_info_once()" instead of open-coding it badly
Using a mutex for "print this warning only once" is so overdesigned as
to be actively offensive to my sensitive stomach.

Just use "pr_info_once()" that already does this, although in a
(harmlessly) racy manner that can in theory cause the message to be
printed twice if more than one CPU races on that "is this the first
time" test.

[ If somebody really cares about that harmless data race (which sounds
  very unlikely indeed), that person can trivially fix printk_once() by
  using a simple atomic access, preferably with an optimistic non-atomic
  test first before even bothering to treat the pointless "make sure it
  is _really_ just once" case.

  A mutex is most definitely never the right primitive to use for
  something like this. ]

Yes, this is a small and meaningless detail in a code path that hardly
matters.  But let's keep some code quality standards here, and not
accept outrageously bad code.

Link: https://lore.kernel.org/lkml/CAHk-=wgV9toS7GU3KmNpj8hCS9SeF+A0voHS8F275_mgLhL4Lw@mail.gmail.com/
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-05 12:50:20 -07:00
Ingo Molnar a4c0e91d1d x86/entry/32: Fix XEN_PV build dependency
xenpv_exc_nmi() and xenpv_exc_debug() are only defined on 64-bit kernels,
but they snuck into the 32-bit build via <asm/identry.h>, causing the link
to fail:

  ld: arch/x86/entry/entry_32.o: in function `asm_xenpv_exc_nmi':
  (.entry.text+0x817): undefined reference to `xenpv_exc_nmi'

  ld: arch/x86/entry/entry_32.o: in function `asm_xenpv_exc_debug':
  (.entry.text+0x827): undefined reference to `xenpv_exc_debug'

Only use them on 64-bit kernels.

Fixes: f41f0824224e: ("x86/entry/xen: Route #DB correctly on Xen PV")
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-05 21:39:23 +02:00
Linus Torvalds 72674d4800 A series of fixes for x86:
- Reset MXCSR in kernel_fpu_begin() to prevent using a stale user space
    value.
 
  - Prevent writing MSR_TEST_CTRL on CPUs which are not explicitly
    whitelisted for split lock detection. Some CPUs which do not support
    it crash even when the MSR is written to 0 which is the default value.
 
  - Fix the XEN PV fallout of the entry code rework
 
  - Fix the 32bit fallout of the entry code rework
 
  - Add more selftests to ensure that these entry problems don't come back.
 
  - Disable 16 bit segments on XEN PV. It's not supported because XEN PV
    does not implement ESPFIX64
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Merge tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Thomas Gleixner:
 "A series of fixes for x86:

   - Reset MXCSR in kernel_fpu_begin() to prevent using a stale user
     space value.

   - Prevent writing MSR_TEST_CTRL on CPUs which are not explicitly
     whitelisted for split lock detection. Some CPUs which do not
     support it crash even when the MSR is written to 0 which is the
     default value.

   - Fix the XEN PV fallout of the entry code rework

   - Fix the 32bit fallout of the entry code rework

   - Add more selftests to ensure that these entry problems don't come
     back.

   - Disable 16 bit segments on XEN PV. It's not supported because XEN
     PV does not implement ESPFIX64"

* tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ldt: Disable 16-bit segments on Xen PV
  x86/entry/32: Fix #MC and #DB wiring on x86_32
  x86/entry/xen: Route #DB correctly on Xen PV
  x86/entry, selftests: Further improve user entry sanity checks
  x86/entry/compat: Clear RAX high bits on Xen PV SYSENTER
  selftests/x86: Consolidate and fix get/set_eflags() helpers
  selftests/x86/syscall_nt: Clear weird flags after each test
  selftests/x86/syscall_nt: Add more flag combinations
  x86/entry/64/compat: Fix Xen PV SYSENTER frame setup
  x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C
  x86/entry: Assert that syscalls are on the right stack
  x86/split_lock: Don't write MSR_TEST_CTRL on CPUs that aren't whitelisted
  x86/fpu: Reset MXCSR to default in kernel_fpu_begin()
2020-07-05 12:23:49 -07:00
Andy Lutomirski cc801833a1 x86/ldt: Disable 16-bit segments on Xen PV
Xen PV doesn't implement ESPFIX64, so they don't work right.  Disable
them.  Also print a warning the first time anyone tries to use a
16-bit segment on a Xen PV guest that would otherwise allow it
to help people diagnose this change in behavior.

This gets us closer to having all x86 selftests pass on Xen PV.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/92b2975459dfe5929ecf34c3896ad920bd9e3f2d.1593795633.git.luto@kernel.org
2020-07-04 19:47:26 +02:00
Andy Lutomirski 13cbc0cd4a x86/entry/32: Fix #MC and #DB wiring on x86_32
DEFINE_IDTENTRY_MCE and DEFINE_IDTENTRY_DEBUG were wired up as non-RAW
on x86_32, but the code expected them to be RAW.

Get rid of all the macro indirection for them on 32-bit and just use
DECLARE_IDTENTRY_RAW and DEFINE_IDTENTRY_RAW directly.

Also add a warning to make sure that we only hit the _kernel paths
in kernel mode.

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/9e90a7ee8e72fd757db6d92e1e5ff16339c1ecf9.1593795633.git.luto@kernel.org
2020-07-04 19:47:26 +02:00
Andy Lutomirski f41f082422 x86/entry/xen: Route #DB correctly on Xen PV
On Xen PV, #DB doesn't use IST. It still needs to be correctly routed
depending on whether it came from user or kernel mode.

Get rid of DECLARE/DEFINE_IDTENTRY_XEN -- it was too hard to follow the
logic.  Instead, route #DB and NMI through DECLARE/DEFINE_IDTENTRY_RAW on
Xen, and do the right thing for #DB.  Also add more warnings to the
exc_debug* handlers to make this type of failure more obvious.

This fixes various forms of corruption that happen when usermode
triggers #DB on Xen PV.

Fixes: 4c0dcd8350 ("x86/entry: Implement user mode C entry points for #DB and #MCE")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/4163e733cce0b41658e252c6c6b3464f33fdff17.1593795633.git.luto@kernel.org
2020-07-04 19:47:25 +02:00
Andy Lutomirski 3c73b81a91 x86/entry, selftests: Further improve user entry sanity checks
Chasing down a Xen bug caused me to realize that the new entry sanity
checks are still fairly weak.  Add some more checks.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/881de09e786ab93ce56ee4a2437ba2c308afe7a9.1593795633.git.luto@kernel.org
2020-07-04 19:47:25 +02:00
Andy Lutomirski db5b2c5a90 x86/entry/compat: Clear RAX high bits on Xen PV SYSENTER
Move the clearing of the high bits of RAX after Xen PV joins the SYSENTER
path so that Xen PV doesn't skip it.

Arguably this code should be deleted instead, but that would belong in the
merge window.

Fixes: ffae641f57 ("x86/entry/64/compat: Fix Xen PV SYSENTER frame setup")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/9d33b3f3216dcab008070f1c28b6091ae7199969.1593795633.git.luto@kernel.org
2020-07-04 19:47:25 +02:00
Christoph Hellwig a3a66c3822 vmalloc: fix the owner argument for the new __vmalloc_node_range callers
Fix the recently added new __vmalloc_node_range callers to pass the
correct values as the owner for display in /proc/vmallocinfo.

Fixes: 800e26b813 ("x86/hyperv: allocate the hypercall page with only read and execute bits")
Fixes: 10d5e97c1b ("arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page")
Fixes: 7a0e27b2a0 ("mm: remove vmalloc_exec")
Reported-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200627075649.2455097-1-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-03 16:15:25 -07:00
Sean Christopherson fa71e9527f KVM: VMX: Use KVM_POSSIBLE_CR*_GUEST_BITS to initialize guest/host masks
Use the "common" KVM_POSSIBLE_CR*_GUEST_BITS defines to initialize the
CR0/CR4 guest host masks instead of duplicating most of the CR4 mask and
open coding the CR0 mask.  SVM doesn't utilize the masks, i.e. the masks
are effectively VMX specific even if they're not named as such.  This
avoids duplicate code, better documents the guest owned CR0 bit, and
eliminates the need for a build-time assertion to keep VMX and x86
synchronized.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200703040422.31536-3-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-03 12:16:33 -04:00
Sean Christopherson 7c83d096ae KVM: x86: Mark CR4.TSD as being possibly owned by the guest
Mark CR4.TSD as being possibly owned by the guest as that is indeed the
case on VMX.  Without TSD being tagged as possibly owned by the guest, a
targeted read of CR4 to get TSD could observe a stale value.  This bug
is benign in the current code base as the sole consumer of TSD is the
emulator (for RDTSC) and the emulator always "reads" the entirety of CR4
when grabbing bits.

Add a build-time assertion in to ensure VMX doesn't hand over more CR4
bits without also updating x86.

Fixes: 52ce3c21ae ("x86,kvm,vmx: Don't trap writes to CR4.TSD")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200703040422.31536-2-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-03 12:16:28 -04:00
Sean Christopherson d74fcfc1f0 KVM: x86: Inject #GP if guest attempts to toggle CR4.LA57 in 64-bit mode
Inject a #GP on MOV CR4 if CR4.LA57 is toggled in 64-bit mode, which is
illegal per Intel's SDM:

  CR4.LA57
    57-bit linear addresses (bit 12 of CR4) ... blah blah blah ...
    This bit cannot be modified in IA-32e mode.

Note, the pseudocode for MOV CR doesn't call out the fault condition,
which is likely why the check was missed during initial development.
This is arguably an SDM bug and will hopefully be fixed in future
release of the SDM.

Fixes: fd8cb43373 ("KVM: MMU: Expose the LA57 feature to VM.")
Cc: stable@vger.kernel.org
Reported-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200703021714.5549-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-03 12:15:56 -04:00
Andy Lutomirski ffae641f57 x86/entry/64/compat: Fix Xen PV SYSENTER frame setup
The SYSENTER frame setup was nonsense.  It worked by accident because the
normal code into which the Xen asm jumped (entry_SYSENTER_32/compat) threw
away SP without touching the stack.  entry_SYSENTER_compat was recently
modified such that it relied on having a valid stack pointer, so now the
Xen asm needs to invoke it with a valid stack.

Fix it up like SYSCALL: use the Xen-provided frame and skip the bare
metal prologue.

Fixes: 1c3e5d3f60 ("x86/entry: Make entry_64_compat.S objtool clean")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lkml.kernel.org/r/947880c41ade688ff4836f665d0c9fcaa9bd1201.1593191971.git.luto@kernel.org
2020-07-01 10:00:26 +02:00
Andy Lutomirski d1721250f3 x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C
The SYSENTER asm (32-bit and compat) contains fixups for regs->sp and
regs->flags.  Move the fixups into C and fix some comments while at it.

This is a valid cleanup all by itself, and it also simplifies the
subsequent patch that will fix Xen PV SYSENTER.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/fe62bef67eda7fac75b8f3dbafccf571dc4ece6b.1593191971.git.luto@kernel.org
2020-07-01 10:00:25 +02:00
Andy Lutomirski c9c26150e6 x86/entry: Assert that syscalls are on the right stack
Now that the entry stack is a full page, it's too easy to regress the
system call entry code and end up on the wrong stack without noticing.
Assert that all system calls (SYSCALL64, SYSCALL32, SYSENTER, and INT80)
are on the right stack and have pt_regs in the right place.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/52059e42bb0ab8551153d012d68f7be18d72ff8e.1593191971.git.luto@kernel.org
2020-07-01 10:00:25 +02:00
Sean Christopherson 009bce1df0 x86/split_lock: Don't write MSR_TEST_CTRL on CPUs that aren't whitelisted
Choo! Choo!  All aboard the Split Lock Express, with direct service to
Wreckage!

Skip split_lock_verify_msr() if the CPU isn't whitelisted as a possible
SLD-enabled CPU model to avoid writing MSR_TEST_CTRL.  MSR_TEST_CTRL
exists, and is writable, on many generations of CPUs.  Writing the MSR,
even with '0', can result in bizarre, undocumented behavior.

This fixes a crash on Haswell when resuming from suspend with a live KVM
guest.  Because APs use the standard SMP boot flow for resume, they will
go through split_lock_init() and the subsequent RDMSR/WRMSR sequence,
which runs even when sld_state==sld_off to ensure SLD is disabled.  On
Haswell (at least, my Haswell), writing MSR_TEST_CTRL with '0' will
succeed and _may_ take the SMT _sibling_ out of VMX root mode.

When KVM has an active guest, KVM performs VMXON as part of CPU onlining
(see kvm_starting_cpu()).  Because SMP boot is serialized, the resulting
flow is effectively:

  on_each_ap_cpu() {
     WRMSR(MSR_TEST_CTRL, 0)
     VMXON
  }

As a result, the WRMSR can disable VMX on a different CPU that has
already done VMXON.  This ultimately results in a #UD on VMPTRLD when
KVM regains control and attempt run its vCPUs.

The above voodoo was confirmed by reworking KVM's VMXON flow to write
MSR_TEST_CTRL prior to VMXON, and to serialize the sequence as above.
Further verification of the insanity was done by redoing VMXON on all
APs after the initial WRMSR->VMXON sequence.  The additional VMXON,
which should VM-Fail, occasionally succeeded, and also eliminated the
unexpected #UD on VMPTRLD.

The damage done by writing MSR_TEST_CTRL doesn't appear to be limited
to VMX, e.g. after suspend with an active KVM guest, subsequent reboots
almost always hang (even when fudging VMXON), a #UD on a random Jcc was
observed, suspend/resume stability is qualitatively poor, and so on and
so forth.

  kernel BUG at arch/x86/kvm/x86.c:386!
  CPU: 1 PID: 2592 Comm: CPU 6/KVM Tainted: G      D
  Hardware name: ASUS Q87M-E/Q87M-E, BIOS 1102 03/03/2014
  RIP: 0010:kvm_spurious_fault+0xf/0x20
  Call Trace:
   vmx_vcpu_load_vmcs+0x1fb/0x2b0
   vmx_vcpu_load+0x3e/0x160
   kvm_arch_vcpu_load+0x48/0x260
   finish_task_switch+0x140/0x260
   __schedule+0x460/0x720
   _cond_resched+0x2d/0x40
   kvm_arch_vcpu_ioctl_run+0x82e/0x1ca0
   kvm_vcpu_ioctl+0x363/0x5c0
   ksys_ioctl+0x88/0xa0
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x4c/0x170
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: dbaba47085 ("x86/split_lock: Rework the initialization flow of split lock detection")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200605192605.7439-1-sean.j.christopherson@intel.com
2020-06-30 14:09:31 +02:00
Paolo Bonzini 5ecad245de KVM: x86: bit 8 of non-leaf PDPEs is not reserved
Bit 8 would be the "global" bit, which does not quite make sense for non-leaf
page table entries.  Intel ignores it; AMD ignores it in PDEs and PDPEs, but
reserves it in PML4Es.

Probably, earlier versions of the AMD manual documented it as reserved in PDPEs
as well, and that behavior made it into KVM as well as kvm-unit-tests; fix it.

Cc: stable@vger.kernel.org
Reported-by: Nadav Amit <namit@vmware.com>
Fixes: a0c0feb579 ("KVM: x86: reserve bit 8 of non-leaf PDPEs and PML4Es in 64-bit mode on AMD", 2014-09-03)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-30 07:07:20 -04:00