Commit Graph

92 Commits

Author SHA1 Message Date
Michael Kelley e1878402ab x86/hyperv: Fix definition of hv_ghcb_pg variable
The percpu variable hv_ghcb_pg is incorrectly defined.  The __percpu
qualifier should be associated with the union hv_ghcb * (i.e.,
a pointer), not with the target of the pointer. This distinction
makes no difference to gcc and the generated code, but sparse
correctly complains.  Fix the definition in the interest of
general correctness in addition to making sparse happy.

No functional change.

Fixes: 0cc4f6d9f0 ("x86/hyperv: Initialize GHCB page in Isolation VM")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1640662315-22260-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-12-28 14:18:47 +00:00
Tianyu Lan 062a5c4260 hyper-v: Enable swiotlb bounce buffer for Isolation VM
hyperv Isolation VM requires bounce buffer support to copy
data from/to encrypted memory and so enable swiotlb force
mode to use swiotlb bounce buffer for DMA transaction.

In Isolation VM with AMD SEV, the bounce buffer needs to be
accessed via extra address space which is above shared_gpa_boundary
(E.G 39 bit address line) reported by Hyper-V CPUID ISOLATION_CONFIG.
The access physical address will be original physical address +
shared_gpa_boundary. The shared_gpa_boundary in the AMD SEV SNP
spec is called virtual top of memory(vTOM). Memory addresses below
vTOM are automatically treated as private while memory above
vTOM is treated as shared.

Swiotlb bounce buffer code calls set_memory_decrypted()
to mark bounce buffer visible to host and map it in extra
address space via memremap. Populate the shared_gpa_boundary
(vTOM) via swiotlb_unencrypted_base variable.

The map function memremap() can't work in the early place
(e.g ms_hyperv_init_platform()) and so call swiotlb_update_mem_
attributes() in the hyperv_init().

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20211213071407.314309-4-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-12-20 18:01:09 +00:00
Sean Christopherson f3e613e72f x86/hyperv: Move required MSRs check to initial platform probing
Explicitly check for MSR_HYPERCALL and MSR_VP_INDEX support when probing
for running as a Hyper-V guest instead of waiting until hyperv_init() to
detect the bogus configuration.  Add messages to give the admin a heads
up that they are likely running on a broken virtual machine setup.

At best, silently disabling Hyper-V is confusing and difficult to debug,
e.g. the kernel _says_ it's using all these fancy Hyper-V features, but
always falls back to the native versions.  At worst, the half baked setup
will crash/hang the kernel.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20211104182239.1302956-3-seanjc@google.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-11-15 12:37:08 +00:00
Sean Christopherson daf972118c x86/hyperv: Fix NULL deref in set_hv_tscchange_cb() if Hyper-V setup fails
Check for a valid hv_vp_index array prior to derefencing hv_vp_index when
setting Hyper-V's TSC change callback.  If Hyper-V setup failed in
hyperv_init(), the kernel will still report that it's running under
Hyper-V, but will have silently disabled nearly all functionality.

  BUG: kernel NULL pointer dereference, address: 0000000000000010
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP
  CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc2+ #75
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:set_hv_tscchange_cb+0x15/0xa0
  Code: <8b> 04 82 8b 15 12 17 85 01 48 c1 e0 20 48 0d ee 00 01 00 f6 c6 08
  ...
  Call Trace:
   kvm_arch_init+0x17c/0x280
   kvm_init+0x31/0x330
   vmx_init+0xba/0x13a
   do_one_initcall+0x41/0x1c0
   kernel_init_freeable+0x1f2/0x23b
   kernel_init+0x16/0x120
   ret_from_fork+0x22/0x30

Fixes: 93286261de ("x86/hyperv: Reenlightenment notifications support")
Cc: stable@vger.kernel.org
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20211104182239.1302956-2-seanjc@google.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-11-15 12:37:08 +00:00
Vitaly Kuznetsov 285f68afa8 x86/hyperv: Protect set_hv_tscchange_cb() against getting preempted
The following issue is observed with CONFIG_DEBUG_PREEMPT when KVM loads:

 KVM: vmx: using Hyper-V Enlightened VMCS
 BUG: using smp_processor_id() in preemptible [00000000] code: systemd-udevd/488
 caller is set_hv_tscchange_cb+0x16/0x80
 CPU: 1 PID: 488 Comm: systemd-udevd Not tainted 5.15.0-rc5+ #396
 Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.0 12/17/2019
 Call Trace:
  dump_stack_lvl+0x6a/0x9a
  check_preemption_disabled+0xde/0xe0
  ? kvm_gen_update_masterclock+0xd0/0xd0 [kvm]
  set_hv_tscchange_cb+0x16/0x80
  kvm_arch_init+0x23f/0x290 [kvm]
  kvm_init+0x30/0x310 [kvm]
  vmx_init+0xaf/0x134 [kvm_intel]
  ...

set_hv_tscchange_cb() can get preempted in between acquiring
smp_processor_id() and writing to HV_X64_MSR_REENLIGHTENMENT_CONTROL. This
is not an issue by itself: HV_X64_MSR_REENLIGHTENMENT_CONTROL is a
partition-wide MSR and it doesn't matter which particular CPU will be
used to receive reenlightenment notifications. The only real problem can
(in theory) be observed if the CPU whose id was acquired with
smp_processor_id() goes offline before we manage to write to the MSR,
the logic in hv_cpu_die() won't be able to reassign it correctly.

Reported-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20211012155005.1613352-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28 11:59:13 +00:00
Wan Jiabing c5989b92fd x86/hyperv: Remove duplicated include in hv_init
Fix following checkinclude.pl warning:
./arch/x86/hyperv/hv_init.c: linux/io.h is included more than once.

The include is in line 13. Remove the duplicated here.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20211026113249.30481-1-wanjiabing@vivo.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28 11:27:58 +00:00
Tianyu Lan faff44069f x86/hyperv: Add Write/Read MSR registers via ghcb page
Hyperv provides GHCB protocol to write Synthetic Interrupt
Controller MSR registers in Isolation VM with AMD SEV SNP
and these registers are emulated by hypervisor directly.
Hyperv requires to write SINTx MSR registers twice. First
writes MSR via GHCB page to communicate with hypervisor
and then writes wrmsr instruction to talk with paravisor
which runs in VMPL0. Guest OS ID MSR also needs to be set
via GHCB page.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-7-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28 11:22:38 +00:00
Tianyu Lan 810a521265 x86/hyperv: Add new hvcall guest address host visibility support
Add new hvcall guest address host visibility support to mark
memory visible to host. Call it inside set_memory_decrypted
/encrypted(). Add HYPERVISOR feature check in the
hv_is_isolation_supported() to optimize in non-virtualization
environment.

Acked-by: Dave Hansen <dave.hansen@intel.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-4-ltykernel@gmail.com
[ wei: fix conflicts with tip ]
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28 11:21:33 +00:00
Tianyu Lan 0cc4f6d9f0 x86/hyperv: Initialize GHCB page in Isolation VM
Hyperv exposes GHCB page via SEV ES GHCB MSR for SNP guest
to communicate with hypervisor. Map GHCB page for all
cpus to read/write MSR register and submit hvcall request
via ghcb page.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-2-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28 10:47:52 +00:00
Praveen Kumar e5d9b714fe x86/hyperv: fix root partition faults when writing to VP assist page MSR
For root partition the VP assist pages are pre-determined by the
hypervisor. The root kernel is not allowed to change them to
different locations. And thus, we are getting below stack as in
current implementation root is trying to perform write to specific
MSR.

    [ 2.778197] unchecked MSR access error: WRMSR to 0x40000073 (tried to write 0x0000000145ac5001) at rIP: 0xffffffff810c1084 (native_write_msr+0x4/0x30)
    [ 2.784867] Call Trace:
    [ 2.791507] hv_cpu_init+0xf1/0x1c0
    [ 2.798144] ? hyperv_report_panic+0xd0/0xd0
    [ 2.804806] cpuhp_invoke_callback+0x11a/0x440
    [ 2.811465] ? hv_resume+0x90/0x90
    [ 2.818137] cpuhp_issue_call+0x126/0x130
    [ 2.824782] __cpuhp_setup_state_cpuslocked+0x102/0x2b0
    [ 2.831427] ? hyperv_report_panic+0xd0/0xd0
    [ 2.838075] ? hyperv_report_panic+0xd0/0xd0
    [ 2.844723] ? hv_resume+0x90/0x90
    [ 2.851375] __cpuhp_setup_state+0x3d/0x90
    [ 2.858030] hyperv_init+0x14e/0x410
    [ 2.864689] ? enable_IR_x2apic+0x190/0x1a0
    [ 2.871349] apic_intr_mode_init+0x8b/0x100
    [ 2.878017] x86_late_time_init+0x20/0x30
    [ 2.884675] start_kernel+0x459/0x4fb
    [ 2.891329] secondary_startup_64_no_verify+0xb0/0xbb

Since the hypervisor already provides the VP assist pages for root
partition, we need to memremap the memory from hypervisor for root
kernel to use. The mapping is done in hv_cpu_init during bringup and is
unmapped in hv_cpu_die during teardown.

Signed-off-by: Praveen Kumar <kumarpraveen@linux.microsoft.com>
Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Link: https://lore.kernel.org/r/20210731120519.17154-1-kumarpraveen@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-08-04 11:56:53 +00:00
Michael Kelley 6dc77fa5ac Drivers: hv: Move Hyper-V misc functionality to arch-neutral code
The check for whether hibernation is possible, and the enabling of
Hyper-V panic notification during kexec, are both architecture neutral.
Move the code from under arch/x86 and into drivers/hv/hv_common.c where
it can also be used for ARM64.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626287687-2045-4-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-15 12:59:45 +00:00
Michael Kelley 9d7cf2c967 Drivers: hv: Add arch independent default functions for some Hyper-V handlers
Architecture independent Hyper-V code calls various arch-specific handlers
when needed.  To aid in supporting multiple architectures, provide weak
defaults that can be overridden by arch-specific implementations where
appropriate.  But when arch-specific overrides aren't needed or haven't
been implemented yet for a particular architecture, these stubs reduce
the amount of clutter under arch/.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626287687-2045-3-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-15 12:59:45 +00:00
Michael Kelley afca4d95dd Drivers: hv: Make portions of Hyper-V init code be arch neutral
The code to allocate and initialize the hv_vp_index array is
architecture neutral. Similarly, the code to allocate and
populate the hypercall input and output arg pages is architecture
neutral.  Move both sets of code out from arch/x86 and into
utility functions in drivers/hv/hv_common.c that can be shared
by Hyper-V initialization on ARM64.

No functional changes. However, the allocation of the hypercall
input and output arg pages is done differently so that the
size is always the Hyper-V page size, even if not the same as
the guest page size (such as with ARM64's 64K page size).

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626287687-2045-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-15 12:59:45 +00:00
Michael Kelley a4d7e8ae4a Drivers: hv: Move Hyper-V extended capability check to arch neutral code
The extended capability query code is currently under arch/x86, but it
is architecture neutral, and is used by arch neutral code in the Hyper-V
balloon driver. Hence the balloon driver fails to build on other
architectures.

Fix by moving the ext cap code out from arch/x86.  Because it is also
called from built-in architecture specific code, it can't be in a module,
so the Makefile treats as built-in even when CONFIG_HYPERV is "m".  Also
drivers/Makefile is tweaked because this is the first occurrence of a
Hyper-V file that is built-in even when CONFIG_HYPERV is "m".

While here, update the hypercall status check to use the new helper
function instead of open coding. No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Link: https://lore.kernel.org/r/1622669804-2016-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-06-05 10:22:34 +00:00
Linus Torvalds 4d480dbf21 hyperv-next for 5.13
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Merge tag 'hyperv-next-signed-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull Hyper-V updates from Wei Liu:

 - VMBus enhancement

 - Free page reporting support for Hyper-V balloon driver

 - Some patches for running Linux as Arm64 Hyper-V guest

 - A few misc clean-up patches

* tag 'hyperv-next-signed-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (30 commits)
  drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status
  x86/hyperv: Move hv_do_rep_hypercall to asm-generic
  video: hyperv_fb: Add ratelimit on error message
  Drivers: hv: vmbus: Increase wait time for VMbus unload
  Drivers: hv: vmbus: Initialize unload_event statically
  Drivers: hv: vmbus: Check for pending channel interrupts before taking a CPU offline
  Drivers: hv: vmbus: Drivers: hv: vmbus: Introduce CHANNELMSG_MODIFYCHANNEL_RESPONSE
  Drivers: hv: vmbus: Introduce and negotiate VMBus protocol version 5.3
  Drivers: hv: vmbus: Use after free in __vmbus_open()
  Drivers: hv: vmbus: remove unused function
  Drivers: hv: vmbus: Remove unused linux/version.h header
  x86/hyperv: remove unused linux/version.h header
  x86/Hyper-V: Support for free page reporting
  x86/hyperv: Fix unused variable 'hi' warning in hv_apic_read
  x86/hyperv: Fix unused variable 'msr_val' warning in hv_qlock_wait
  hv: hyperv.h: a few mundane typo fixes
  drivers: hv: Fix EXPORT_SYMBOL and tab spaces issue
  Drivers: hv: vmbus: Drop error message when 'No request id available'
  asm-generic/hyperv: Add missing function prototypes per -W1 warnings
  clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts
  ...
2021-04-26 10:44:16 -07:00
Joseph Salisbury 753ed9c95c drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status
There is not a consistent pattern for checking Hyper-V hypercall status.
Existing code uses a number of variants.  The variants work, but a consistent
pattern would improve the readability of the code, and be more conformant
to what the Hyper-V TLFS says about hypercall status.

Implemented new helper functions hv_result(), hv_result_success(), and
hv_repcomp().  Changed the places where hv_do_hypercall() and related variants
are used to use the helper functions.

Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1618620183-9967-2-git-send-email-joseph.salisbury@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-04-21 09:49:19 +00:00
Sunil Muthuswamy 6dc2a774cb x86/Hyper-V: Support for free page reporting
Linux has support for free page reporting now (36e66c554b) for
virtualized environment. On Hyper-V when virtually backed VMs are
configured, Hyper-V will advertise cold memory discard capability,
when supported. This patch adds the support to hook into the free
page reporting infrastructure and leverage the Hyper-V cold memory
discard hint hypercall to report/free these pages back to the host.

Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Tested-by: Matheus Castello <matheus@castello.eng.br>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/SN4PR2101MB0880121FA4E2FEC67F35C1DCC0649@SN4PR2101MB0880.namprd21.prod.outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-24 11:35:24 +00:00
Ingo Molnar d9f6e12fb0 x86: Fix various typos in comments
Fix ~144 single-word typos in arch/x86/ code comments.

Doing this in a single commit should reduce the churn.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org
2021-03-18 15:31:53 +01:00
Michael Kelley ec866be6ec clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts
STIMER0 interrupts are most naturally modeled as per-cpu IRQs. But
because x86/x64 doesn't have per-cpu IRQs, the core STIMER0 interrupt
handling machinery is done in code under arch/x86 and Linux IRQs are
not used. Adding support for ARM64 means adding equivalent code
using per-cpu IRQs under arch/arm64.

A better model is to treat per-cpu IRQs as the normal path (which it is
for modern architectures), and the x86/x64 path as the exception. Do this
by incorporating standard Linux per-cpu IRQ allocation into the main
SITMER0 driver code, and bypass it in the x86/x64 exception case. For
x86/x64, special case code is retained under arch/x86, but no STIMER0
interrupt handling code is needed under arch/arm64.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/1614721102-2241-11-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-08 17:33:00 +00:00
Michael Kelley b548a77427 Drivers: hv: vmbus: Move hyperv_report_panic_msg to arch neutral code
With the new Hyper-V MSR set function, hyperv_report_panic_msg() can be
architecture neutral, so move it out from under arch/x86 and merge into
hv_kmsg_dump(). This move also avoids needing a separate implementation
under arch/arm64.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/1614721102-2241-5-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-08 17:32:59 +00:00
Michael Kelley f3c5e63c36 Drivers: hv: Redo Hyper-V synthetic MSR get/set functions
Current code defines a separate get and set macro for each Hyper-V
synthetic MSR used by the VMbus driver. Furthermore, the get macro
can't be converted to a standard function because the second argument
is modified in place, which is somewhat bad form.

Redo this by providing a single get and a single set function that
take a parameter specifying the MSR to be operated on. Fixup usage
of the get function. Calling locations are no more complex than before,
but the code under arch/x86 and the upcoming code under arch/arm64
is significantly simplified.

Also standardize the names of Hyper-V synthetic MSRs that are
architecture neutral. But keep the old x86-specific names as aliases
that can be removed later when all references (particularly in KVM
code) have been cleaned up in a separate patch series.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/1614721102-2241-4-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-08 17:32:59 +00:00
Michael Kelley ca48739e59 Drivers: hv: vmbus: Move Hyper-V page allocator to arch neutral code
The Hyper-V page allocator functions are implemented in an architecture
neutral way.  Move them into the architecture neutral VMbus module so
a separate implementation for ARM64 is not needed.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/1614721102-2241-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-08 17:32:59 +00:00
Wei Liu e39397d1fd x86/hyperv: implement an MSI domain for root partition
When Linux runs as the root partition on Microsoft Hypervisor, its
interrupts are remapped.  Linux will need to explicitly map and unmap
interrupts for hardware.

Implement an MSI domain to issue the correct hypercalls. And initialize
this irq domain as the default MSI irq domain.

Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-16-wei.liu@kernel.org
2021-02-11 08:47:07 +00:00
Wei Liu 80f73c9f74 x86/hyperv: handling hypercall page setup for root
When Linux is running as the root partition, the hypercall page will
have already been setup by Hyper-V. Copy the content over to the
allocated page.

Add checks to hv_suspend & co to bail early because they are not
supported in this setup yet.

Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Co-Developed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-8-wei.liu@kernel.org
2021-02-11 08:47:06 +00:00
Wei Liu 99a0f46af6 x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary
We will need the partition ID for executing some hypercalls later.

Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-7-wei.liu@kernel.org
2021-02-11 08:47:06 +00:00
Wei Liu 5d0f077e0f x86/hyperv: allocate output arg pages if required
When Linux runs as the root partition, it will need to make hypercalls
which return data from the hypervisor.

Allocate pages for storing results when Linux runs as the root
partition.

Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-6-wei.liu@kernel.org
2021-02-11 08:47:06 +00:00
Andrea Parri (Microsoft) a6c76bb08d x86/hyperv: Load/save the Isolation Configuration leaf
If bit 22 of Group B Features is set, the guest has access to the
Isolation Configuration CPUID leaf.  On x86, the first four bits
of EAX in this leaf provide the isolation type of the partition;
we entail three isolation types: 'SNP' (hardware-based isolation),
'VBS' (software-based isolation), and 'NONE' (no isolation).

Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/r/20210201144814.2701-2-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-02-11 08:47:05 +00:00
Dexuan Cui fff7b5e6ee x86/hyperv: Initialize clockevents after LAPIC is initialized
With commit 4df4cb9e99, the Hyper-V direct-mode STIMER is actually
initialized before LAPIC is initialized: see

  apic_intr_mode_init()

    x86_platform.apic_post_init()
      hyperv_init()
        hv_stimer_alloc()

    apic_bsp_setup()
      setup_local_APIC()

setup_local_APIC() temporarily disables LAPIC, initializes it and
re-eanble it.  The direct-mode STIMER depends on LAPIC, and when it's
registered, it can be programmed immediately and the timer can fire
very soon:

  hv_stimer_init
    clockevents_config_and_register
      clockevents_register_device
        tick_check_new_device
          tick_setup_device
            tick_setup_periodic(), tick_setup_oneshot()
              clockevents_program_event

When the timer fires in the hypervisor, if the LAPIC is in the
disabled state, new versions of Hyper-V ignore the event and don't inject
the timer interrupt into the VM, and hence the VM hangs when it boots.

Note: when the VM starts/reboots, the LAPIC is pre-enabled by the
firmware, so the window of LAPIC being temporarily disabled is pretty
small, and the issue can only happen once out of 100~200 reboots for
a 40-vCPU VM on one dev host, and on another host the issue doesn't
reproduce after 2000 reboots.

The issue is more noticeable for kdump/kexec, because the LAPIC is
disabled by the first kernel, and stays disabled until the kdump/kexec
kernel enables it. This is especially an issue to a Generation-2 VM
(for which Hyper-V doesn't emulate the PIT timer) when CONFIG_HZ=1000
(rather than CONFIG_HZ=250) is used.

Fix the issue by moving hv_stimer_alloc() to a later place where the
LAPIC timer is initialized.

Fixes: 4df4cb9e99 ("x86/hyperv: Initialize clockevents earlier in CPU onlining")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by:  Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210116223136.13892-1-decui@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-01-17 15:20:50 +00:00
Dexuan Cui dfe94d4086 x86/hyperv: Fix kexec panic/hang issues
Currently the kexec kernel can panic or hang due to 2 causes:

1) hv_cpu_die() is not called upon kexec, so the hypervisor corrupts the
old VP Assist Pages when the kexec kernel runs. The same issue is fixed
for hibernation in commit 421f090c81 ("x86/hyperv: Suspend/resume the
VP assist page for hibernation"). Now fix it for kexec.

2) hyperv_cleanup() is called too early. In the kexec path, the other CPUs
are stopped in hv_machine_shutdown() -> native_machine_shutdown(), so
between hv_kexec_handler() and native_machine_shutdown(), the other CPUs
can still try to access the hypercall page and cause panic. The workaround
"hv_hypercall_pg = NULL;" in hyperv_cleanup() is unreliabe. Move
hyperv_cleanup() to a better place.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20201222065541.24312-1-decui@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-01-05 17:52:04 +00:00
Joseph Salisbury dfc53baae3 x86/hyperv: Remove aliases with X64 in their name
In the architecture independent version of hyperv-tlfs.h, commit c55a844f46
removed the "X64" in the symbol names so they would make sense for both x86 and
ARM64.  That commit added aliases with the "X64" in the x86 version of hyperv-tlfs.h 
so that existing x86 code would continue to compile.

As a cleanup, update the x86 code to use the symbols without the "X64", then remove 
the aliases.  There's no functional change.

Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/1601130386-11111-1-git-send-email-jsalisbury@linux.microsoft.com
2020-09-27 11:34:54 +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
Christoph Hellwig 800e26b813 x86/hyperv: allocate the hypercall page with only read and execute bits
Patch series "fix a hyperv W^X violation and remove vmalloc_exec"

Dexuan reported a W^X violation due to the fact that the hyper hypercall
page due switching it to be allocated using vmalloc_exec.

The problem is that PAGE_KERNEL_EXEC as used by vmalloc_exec actually
sets writable permissions in the pte.  This series fixes the issue by
switching to the low-level __vmalloc_node_range interface that allows
specifing more detailed permissions instead.  It then also open codes
the other two callers and removes the somewhat confusing vmalloc_exec
interface.

Peter noted that the hyper hypercall page allocation also has another
long standing issue in that it shouldn't use the full vmalloc but just
the module space.  This issue is so far theoretical as the allocation is
done early in the boot process.  I plan to fix it with another bigger
series for 5.9.

This patch (of 3):

Avoid a W^X violation cause by the fact that PAGE_KERNEL_EXEC includes
the writable bit.

For this resurrect the removed PAGE_KERNEL_RX definition, but as
PAGE_KERNEL_ROX to match arm64 and powerpc.

Link: http://lkml.kernel.org/r/20200618064307.32739-2-hch@lst.de
Fixes: 78bb17f76e ("x86/hyperv: use vmalloc_exec for the hypercall page")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Dexuan Cui <decui@microsoft.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-26 00:27:38 -07:00
Thomas Gleixner a16be368dd x86/entry: Convert various hypervisor vectors to IDTENTRY_SYSVEC
Convert various hypervisor vectors to IDTENTRY_SYSVEC:

  - Implement the C entry point with DEFINE_IDTENTRY_SYSVEC
  - Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC
  - Remove the ASM idtentries in 64-bit
  - Remove the BUILD_INTERRUPT entries in 32-bit
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20200521202119.647997594@linutronix.de
2020-06-11 15:15:15 +02:00
Christoph Hellwig 88dca4ca5a mm: remove the pgprot argument to __vmalloc
The pgprot argument to __vmalloc is always PAGE_KERNEL now, so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com> [hyperv]
Acked-by: Gao Xiang <xiang@kernel.org> [erofs]
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Wei Liu <wei.liu@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-22-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-02 10:59:11 -07:00
Christoph Hellwig 78bb17f76e x86/hyperv: use vmalloc_exec for the hypercall page
Patch series "decruft the vmalloc API", v2.

Peter noticed that with some dumb luck you can toast the kernel address
space with exported vmalloc symbols.

I used this as an opportunity to decruft the vmalloc.c API and make it
much more systematic.  This also removes any chance to create vmalloc
mappings outside the designated areas or using executable permissions
from modules.  Besides that it removes more than 300 lines of code.

This patch (of 29):

Use the designated helper for allocating executable kernel memory, and
remove the now unused PAGE_KERNEL_RX define.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200414131348.444715-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200414131348.444715-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-02 10:59:10 -07:00
Vitaly Kuznetsov 38dce4195f x86/hyperv: Properly suspend/resume reenlightenment notifications
Errors during hibernation with reenlightenment notifications enabled were
reported:

 [   51.730435] PM: hibernation entry
 [   51.737435] PM: Syncing filesystems ...
 ...
 [   54.102216] Disabling non-boot CPUs ...
 [   54.106633] smpboot: CPU 1 is now offline
 [   54.110006] unchecked MSR access error: WRMSR to 0x40000106 (tried to
     write 0x47c72780000100ee) at rIP: 0xffffffff90062f24
     native_write_msr+0x4/0x20)
 [   54.110006] Call Trace:
 [   54.110006]  hv_cpu_die+0xd9/0xf0
 ...

Normally, hv_cpu_die() just reassigns reenlightenment notifications to some
other CPU when the CPU receiving them goes offline. Upon hibernation, there
is no other CPU which is still online so cpumask_any_but(cpu_online_mask)
returns >= nr_cpu_ids and using it as hv_vp_index index is incorrect.
Disable the feature when cpumask_any_but() fails.

Also, as we now disable reenlightenment notifications upon hibernation we
need to restore them on resume. Check if hv_reenlightenment_cb was
previously set and restore from hv_resume().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20200512160153.134467-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-05-13 15:02:03 +00:00
Dexuan Cui 421f090c81 x86/hyperv: Suspend/resume the VP assist page for hibernation
Unlike the other CPUs, CPU0 is never offlined during hibernation, so in the
resume path, the "new" kernel's VP assist page is not suspended (i.e. not
disabled), and later when we jump to the "old" kernel, the page is not
properly re-enabled for CPU0 with the allocated page from the old kernel.

So far, the VP assist page is used by hv_apic_eoi_write(), and is also
used in the case of nested virtualization (running KVM atop Hyper-V).

For hv_apic_eoi_write(), when the page is not properly re-enabled,
hvp->apic_assist is always 0, so the HV_X64_MSR_EOI MSR is always written.
This is not ideal with respect to performance, but Hyper-V can still
correctly handle this according to the Hyper-V spec; nevertheless, Linux
still must update the Hyper-V hypervisor with the correct VP assist page
to prevent Hyper-V from writing to the stale page, which causes guest
memory corruption and consequently may have caused the hangs and triple
faults seen during non-boot CPUs resume.

Fix the issue by calling hv_cpu_die()/hv_cpu_init() in the syscore ops.
Without the fix, hibernation can fail at a rate of 1/300 ~ 1/500.
With the fix, hibernation can pass a long-haul test of 2000 runs.

In the case of nested virtualization, disabling/reenabling the assist
page upon hibernation may be unsafe if there are active L2 guests.
It looks KVM should be enhanced to abort the hibernation request if
there is any active L2 guest.

Fixes: 05bd330a7f ("x86/hyperv: Suspend/resume the hypercall page for hibernation")
Cc: stable@vger.kernel.org
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/r/1587437171-2472-1-git-send-email-decui@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-04-21 10:03:19 +01:00
Tianyu Lan f3a99e761e x86/Hyper-V: Report crash data in die() when panic_on_oops is set
When oops happens with panic_on_oops unset, the oops
thread is killed by die() and system continues to run.
In such case, guest should not report crash register
data to host since system still runs. Check panic_on_oops
and return directly in hyperv_report_panic() when the function
is called in the die() and panic_on_oops is unset. Fix it.

Fixes: 7ed4325a44 ("Drivers: hv: vmbus: Make panic reporting to be more useful")
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200406155331.2105-7-Tianyu.Lan@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-04-11 17:19:07 +01:00
Dexuan Cui 05bd330a7f x86/hyperv: Suspend/resume the hypercall page for hibernation
For hibernation the hypercall page must be disabled before the hibernation
image is created so that subsequent hypercall operations fail safely. On
resume the hypercall page has to be restored and reenabled to ensure proper
operation of the resumed kernel.

Implement the necessary suspend/resume callbacks.

[ tglx: Decrypted changelog ]

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1578350559-130275-1-git-send-email-decui@microsoft.com
2020-02-01 09:41:16 +01:00
Linus Torvalds 0dd0c8f7db - Support for new VMBus protocols (Andrea Parri).
- Hibernation support (Dexuan Cui).
 - Latency testing framework (Branden Bonaby).
 - Decoupling Hyper-V page size from guest page size (Himadri Pandya).
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Merge tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull Hyper-V updates from Sasha Levin:

 - support for new VMBus protocols (Andrea Parri)

 - hibernation support (Dexuan Cui)

 - latency testing framework (Branden Bonaby)

 - decoupling Hyper-V page size from guest page size (Himadri Pandya)

* tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (22 commits)
  Drivers: hv: vmbus: Fix crash handler reset of Hyper-V synic
  drivers/hv: Replace binary semaphore with mutex
  drivers: iommu: hyperv: Make HYPERV_IOMMU only available on x86
  HID: hyperv: Add the support of hibernation
  hv_balloon: Add the support of hibernation
  x86/hyperv: Implement hv_is_hibernation_supported()
  Drivers: hv: balloon: Remove dependencies on guest page size
  Drivers: hv: vmbus: Remove dependencies on guest page size
  x86: hv: Add function to allocate zeroed page for Hyper-V
  Drivers: hv: util: Specify ring buffer size using Hyper-V page size
  Drivers: hv: Specify receive buffer size using Hyper-V page size
  tools: hv: add vmbus testing tool
  drivers: hv: vmbus: Introduce latency testing
  video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver
  video: hyperv: hyperv_fb: Obtain screen resolution from Hyper-V host
  hv_netvsc: Add the support of hibernation
  hv_sock: Add the support of hibernation
  video: hyperv_fb: Add the support of hibernation
  scsi: storvsc: Add the support of hibernation
  Drivers: hv: vmbus: Add module parameter to cap the VMBus version
  ...
2019-11-30 14:50:51 -08:00
Dexuan Cui b96f86534f x86/hyperv: Implement hv_is_hibernation_supported()
The API will be used by the hv_balloon and hv_vmbus drivers.

Balloon up/down and hot-add of memory must not be active if the user
wants the Linux VM to support hibernation, because they are incompatible
with hibernation according to Hyper-V team, e.g. upon suspend the
balloon VSP doesn't save any info about the ballooned-out pages (if any);
so, after Linux resumes, Linux balloon VSC expects that the VSP will
return the pages if Linux is under memory pressure, but the VSP will
never do that, since the VSP thinks it never stole the pages from the VM.

So, if the user wants Linux VM to support hibernation, Linux must forbid
balloon up/down and hot-add, and the only functionality of the balloon VSC
driver is reporting the VM's memory pressure to the host.

Ideally, when Linux detects that the user wants it to support hibernation,
the balloon VSC should tell the VSP that it does not support ballooning
and hot-add. However, the current version of the VSP requires the VSC
should support these capabilities, otherwise the capability negotiation
fails and the VSC can not load at all, so with the later changes to the
VSC driver, Linux VM still reports to the VSP that the VSC supports these
capabilities, but the VSC ignores the VSP's requests of balloon up/down
and hot add, and reports an error to the VSP, when applicable. BTW, in
the future the balloon VSP driver will allow the VSC to not support the
capabilities of balloon up/down and hot add.

The ACPI S4 state is not a must for hibernation to work, because Linux is
able to hibernate as long as the system can shut down. However in practice
we decide to artificially use the presence of the virtual ACPI S4 state as
an indicator of the user's intent of using hibernation, because Linux VM
must find a way to know if the user wants to use the hibernation feature
or not.

By default, Hyper-V does not enable the virtual ACPI S4 state; on recent
Hyper-V hosts (e.g. RS5, 19H1), the administrator is able to enable the
state for a VM by WMI commands.

Once all the vmbus and VSC patches for the hibernation feature are
accepted, an extra patch will be submitted to forbid hibernation if the
virtual ACPI S4 state is absent, i.e. hv_is_hibernation_supported() is
false.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-21 20:10:45 -05:00
Himadri Pandya fa36dcdf8b x86: hv: Add function to allocate zeroed page for Hyper-V
Hyper-V assumes page size to be 4K. While this assumption holds true on
x86 architecture, it might not  be true for ARM64 architecture. Hence
define hyper-v specific function to allocate a zeroed page which can
have a different implementation on ARM64 architecture to handle the
conflict between hyper-v's assumed page size and actual guest page size.

Signed-off-by: Himadri Pandya <himadri18.07@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-21 20:10:45 -05:00
Michael Kelley 4df4cb9e99 x86/hyperv: Initialize clockevents earlier in CPU onlining
Hyper-V has historically initialized stimer-based clockevents late in the
process of onlining a CPU because clockevents depend on stimer
interrupts. In the original Hyper-V design, stimer interrupts generate a
VMbus message, so the VMbus machinery must be running first, and VMbus
can't be initialized until relatively late. On x86/64, LAPIC timer based
clockevents are used during early initialization before VMbus and
stimer-based clockevents are ready, and again during CPU offlining after
the stimer clockevents have been shut down.

Unfortunately, this design creates problems when offlining CPUs for
hibernation or other purposes. stimer-based clockevents are shut down
relatively early in the offlining process, so clockevents_unbind_device()
must be used to fallback to the LAPIC-based clockevents for the remainder
of the offlining process.  Furthermore, the late initialization and early
shutdown of stimer-based clockevents doesn't work well on ARM64 since there
is no other timer like the LAPIC to fallback to. So CPU onlining and
offlining doesn't work properly.

Fix this by recognizing that stimer Direct Mode is the normal path for
newer versions of Hyper-V on x86/64, and the only path on other
architectures. With stimer Direct Mode, stimer interrupts don't require any
VMbus machinery. stimer clockevents can be initialized and shut down
consistent with how it is done for other clockevent devices. While the old
VMbus-based stimer interrupts must still be supported for backward
compatibility on x86, that mode of operation can be treated as legacy.

So add a new Hyper-V stimer entry in the CPU hotplug state list, and use
that new state when in Direct Mode. Update the Hyper-V clocksource driver
to allocate and initialize stimer clockevents earlier during boot. Update
Hyper-V initialization and the VMbus driver to use this new design. As a
result, the LAPIC timer is no longer used during boot or CPU
onlining/offlining and clockevents_unbind_device() is not called.  But
retain the old design as a legacy implementation for older versions of
Hyper-V that don't support Direct Mode.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Link: https://lkml.kernel.org/r/1573607467-9456-1-git-send-email-mikelley@microsoft.com
2019-11-15 10:33:49 +01:00
Linus Torvalds 7f2444d38f Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core timer updates from Thomas Gleixner:
 "Timers and timekeeping updates:

   - A large overhaul of the posix CPU timer code which is a preparation
     for moving the CPU timer expiry out into task work so it can be
     properly accounted on the task/process.

     An update to the bogus permission checks will come later during the
     merge window as feedback was not complete before heading of for
     travel.

   - Switch the timerqueue code to use cached rbtrees and get rid of the
     homebrewn caching of the leftmost node.

   - Consolidate hrtimer_init() + hrtimer_init_sleeper() calls into a
     single function

   - Implement the separation of hrtimers to be forced to expire in hard
     interrupt context even when PREEMPT_RT is enabled and mark the
     affected timers accordingly.

   - Implement a mechanism for hrtimers and the timer wheel to protect
     RT against priority inversion and live lock issues when a (hr)timer
     which should be canceled is currently executing the callback.
     Instead of infinitely spinning, the task which tries to cancel the
     timer blocks on a per cpu base expiry lock which is held and
     released by the (hr)timer expiry code.

   - Enable the Hyper-V TSC page based sched_clock for Hyper-V guests
     resulting in faster access to timekeeping functions.

   - Updates to various clocksource/clockevent drivers and their device
     tree bindings.

   - The usual small improvements all over the place"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
  posix-cpu-timers: Fix permission check regression
  posix-cpu-timers: Always clear head pointer on dequeue
  hrtimer: Add a missing bracket and hide `migration_base' on !SMP
  posix-cpu-timers: Make expiry_active check actually work correctly
  posix-timers: Unbreak CONFIG_POSIX_TIMERS=n build
  tick: Mark sched_timer to expire in hard interrupt context
  hrtimer: Add kernel doc annotation for HRTIMER_MODE_HARD
  x86/hyperv: Hide pv_ops access for CONFIG_PARAVIRT=n
  posix-cpu-timers: Utilize timerqueue for storage
  posix-cpu-timers: Move state tracking to struct posix_cputimers
  posix-cpu-timers: Deduplicate rlimit handling
  posix-cpu-timers: Remove pointless comparisons
  posix-cpu-timers: Get rid of 64bit divisions
  posix-cpu-timers: Consolidate timer expiry further
  posix-cpu-timers: Get rid of zero checks
  rlimit: Rewrite non-sensical RLIMIT_CPU comment
  posix-cpu-timers: Respect INFINITY for hard RTTIME limit
  posix-cpu-timers: Switch thread group sampling to array
  posix-cpu-timers: Restructure expiry array
  posix-cpu-timers: Remove cputime_expires
  ...
2019-09-17 12:35:15 -07:00
Tianyu Lan bd00cd52d5 clocksource/drivers/hyperv: Add Hyper-V specific sched clock function
Hyper-V guests use the default native_sched_clock() in
pv_ops.time.sched_clock on x86. But native_sched_clock() directly uses the
raw TSC value, which can be discontinuous in a Hyper-V VM.
    
Add the generic hv_setup_sched_clock() to set the sched clock function
appropriately. On x86, this sets pv_ops.time.sched_clock to read the
Hyper-V reference TSC value that is scaled and adjusted to be continuous.
    
Also move the Hyper-V reference TSC initialization much earlier in the boot
process so no discontinuity is observed when pv_ops.time.sched_clock
calculates its offset.

[ tglx: Folded build fix ]

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lkml.kernel.org/r/20190814123216.32245-3-Tianyu.Lan@microsoft.com
2019-08-23 16:59:54 +02:00
Maya Nakamura 8c3e44bde7 x86/hyperv: Add functions to allocate/deallocate page for Hyper-V
Introduce two new functions, hv_alloc_hyperv_page() and
hv_free_hyperv_page(), to allocate/deallocate memory with the size and
alignment that Hyper-V expects as a page. Although currently they are not
used, they are ready to be used to allocate/deallocate memory on x86 when
their ARM64 counterparts are implemented, keeping symmetry between
architectures with potentially different guest page sizes.

Signed-off-by: Maya Nakamura <m.maya.nakamura@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/lkml/alpine.DEB.2.21.1906272334560.32342@nanos.tec.linutronix.de/
Link: https://lore.kernel.org/lkml/87muindr9c.fsf@vitty.brq.redhat.com/
Link: https://lkml.kernel.org/r/706b2e71eb3e587b5f8801e50f090fae2a00e35d.1562916939.git.m.maya.nakamura@gmail.com
2019-07-22 11:06:45 +02:00
Dexuan Cui e320ab3cec x86/hyper-v: Zero out the VP ASSIST PAGE on allocation
The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's Section
5.2.1 "GPA Overlay Pages" for the details) and here is an excerpt:

"The hypervisor defines several special pages that "overlay" the guest's
 Guest Physical Addresses (GPA) space. Overlays are addressed GPA but are
 not included in the normal GPA map maintained internally by the hypervisor.
 Conceptually, they exist in a separate map that overlays the GPA map.

 If a page within the GPA space is overlaid, any SPA page mapped to the
 GPA page is effectively "obscured" and generally unreachable by the
 virtual processor through processor memory accesses.

 If an overlay page is disabled, the underlying GPA page is "uncovered",
 and an existing mapping becomes accessible to the guest."

SPA = System Physical Address = the final real physical address.

When a CPU (e.g. CPU1) is onlined, hv_cpu_init() allocates the VP ASSIST
PAGE and enables the EOI optimization for this CPU by writing the MSR
HV_X64_MSR_VP_ASSIST_PAGE. From now on, hvp->apic_assist belongs to the
special SPA page, and this CPU *always* uses hvp->apic_assist (which is
shared with the hypervisor) to decide if it needs to write the EOI MSR.

When a CPU is offlined then on the outgoing CPU:
1. hv_cpu_die() disables the EOI optimizaton for this CPU, and from
   now on hvp->apic_assist belongs to the original "normal" SPA page;
2. the remaining work of stopping this CPU is done
3. this CPU is completely stopped.

Between 1 and 3, this CPU can still receive interrupts (e.g. reschedule
IPIs from CPU0, and Local APIC timer interrupts), and this CPU *must* write
the EOI MSR for every interrupt received, otherwise the hypervisor may not
deliver further interrupts, which may be needed to completely stop the CPU.

So, after the EOI optimization is disabled in hv_cpu_die(), it's required
that the hvp->apic_assist's bit0 is zero, which is not guaranteed by the
current allocation mode because it lacks __GFP_ZERO. As a consequence the
bit might be set and interrupt handling would not write the EOI MSR causing
interrupt delivery to become stuck.

Add the missing __GFP_ZERO to the allocation.

Note 1: after the "normal" SPA page is allocted and zeroed out, neither the
hypervisor nor the guest writes into the page, so the page remains with
zeros.

Note 2: see Section 10.3.5 "EOI Assist" for the details of the EOI
optimization. When the optimization is enabled, the guest can still write
the EOI MSR register irrespective of the "No EOI required" value, but
that's slower than the optimized assist based variant.

Fixes: ba696429d2 ("x86/hyper-v: Implement EOI assist")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/ <PU1P153MB0169B716A637FABF07433C04BFCB0@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM
2019-07-19 09:48:15 +02:00
Michael Kelley dd2cb34861 clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic
Continue consolidating Hyper-V clock and timer code into an ISA
independent Hyper-V clocksource driver.

Move the existing clocksource code under drivers/hv and arch/x86 to the new
clocksource driver while separating out the ISA dependencies. Update
Hyper-V initialization to call initialization and cleanup routines since
the Hyper-V synthetic clock is not independently enumerated in ACPI.

Update Hyper-V clocksource users in KVM and VDSO to get definitions from
the new include file.

No behavior is changed and no new functionality is added.

Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: "bp@alien8.de" <bp@alien8.de>
Cc: "will.deacon@arm.com" <will.deacon@arm.com>
Cc: "catalin.marinas@arm.com" <catalin.marinas@arm.com>
Cc: "mark.rutland@arm.com" <mark.rutland@arm.com>
Cc: "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>
Cc: "olaf@aepfle.de" <olaf@aepfle.de>
Cc: "apw@canonical.com" <apw@canonical.com>
Cc: "jasowang@redhat.com" <jasowang@redhat.com>
Cc: "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>
Cc: Sunil Muthuswamy <sunilmut@microsoft.com>
Cc: KY Srinivasan <kys@microsoft.com>
Cc: "sashal@kernel.org" <sashal@kernel.org>
Cc: "vincenzo.frascino@arm.com" <vincenzo.frascino@arm.com>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
Cc: "linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>
Cc: "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>
Cc: "arnd@arndb.de" <arnd@arndb.de>
Cc: "linux@armlinux.org.uk" <linux@armlinux.org.uk>
Cc: "ralf@linux-mips.org" <ralf@linux-mips.org>
Cc: "paul.burton@mips.com" <paul.burton@mips.com>
Cc: "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>
Cc: "salyzyn@android.com" <salyzyn@android.com>
Cc: "pcc@google.com" <pcc@google.com>
Cc: "shuah@kernel.org" <shuah@kernel.org>
Cc: "0x7f454c46@gmail.com" <0x7f454c46@gmail.com>
Cc: "linux@rasmusvillemoes.dk" <linux@rasmusvillemoes.dk>
Cc: "huw@codeweavers.com" <huw@codeweavers.com>
Cc: "sfr@canb.auug.org.au" <sfr@canb.auug.org.au>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>
Cc: "rkrcmar@redhat.com" <rkrcmar@redhat.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Link: https://lkml.kernel.org/r/1561955054-1838-3-git-send-email-mikelley@microsoft.com
2019-07-03 11:00:59 +02:00
Thomas Gleixner 43aa31327b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 280
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose good title or non infringement see
  the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 9 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141900.459653302@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:36:36 +02:00
Kangjie Lu 534c89c22e x86/hyperv: Prevent potential NULL pointer dereference
The page allocation in hv_cpu_init() can fail, but the code does not
have a check for that.

Add a check and return -ENOMEM when the allocation fails.

[ tglx: Massaged changelog ]

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Acked-by: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: pakki001@umn.edu
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-hyperv@vger.kernel.org
Link: https://lkml.kernel.org/r/20190314054651.1315-1-kjlu@umn.edu
2019-03-21 12:24:39 +01:00