Commit Graph

2296 Commits

Author SHA1 Message Date
Linus Torvalds 34f4335c16 * Fix syzkaller NULL pointer dereference
* Fix TDP MMU performance issue with disabling dirty logging
 * Fix 5.14 regression with SVM TSC scaling
 * Fix indefinite stall on applying live patches
 * Fix unstable selftest
 * Fix memory leak from wrong copy-and-paste
 * Fix missed PV TLB flush when racing with emulation
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:

 - syzkaller NULL pointer dereference

 - TDP MMU performance issue with disabling dirty logging

 - 5.14 regression with SVM TSC scaling

 - indefinite stall on applying live patches

 - unstable selftest

 - memory leak from wrong copy-and-paste

 - missed PV TLB flush when racing with emulation

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: do not report a vCPU as preempted outside instruction boundaries
  KVM: x86: do not set st->preempted when going back to user space
  KVM: SVM: fix tsc scaling cache logic
  KVM: selftests: Make hyperv_clock selftest more stable
  KVM: x86/MMU: Zap non-leaf SPTEs when disabling dirty logging
  x86: drop bogus "cc" clobber from __try_cmpxchg_user_asm()
  KVM: x86/mmu: Check every prev_roots in __kvm_mmu_free_obsolete_roots()
  entry/kvm: Exit to user mode when TIF_NOTIFY_SIGNAL is set
  KVM: Don't null dereference ops->destroy
2022-06-08 09:16:31 -07:00
Alexey Kardashevskiy e8bc242701 KVM: Don't null dereference ops->destroy
A KVM device cleanup happens in either of two callbacks:
1) destroy() which is called when the VM is being destroyed;
2) release() which is called when a device fd is closed.

Most KVM devices use 1) but Book3s's interrupt controller KVM devices
(XICS, XIVE, XIVE-native) use 2) as they need to close and reopen during
the machine execution. The error handling in kvm_ioctl_create_device()
assumes destroy() is always defined which leads to NULL dereference as
discovered by Syzkaller.

This adds a checks for destroy!=NULL and adds a missing release().

This is not changing kvm_destroy_devices() as devices with defined
release() should have been removed from the KVM devices list by then.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-07 11:18:59 -04:00
Linus Torvalds 176882156a VFIO updates for v5.19-rc1
- Improvements to mlx5 vfio-pci variant driver, including support
    for parallel migration per PF (Yishai Hadas)
 
  - Remove redundant iommu_present() check (Robin Murphy)
 
  - Ongoing refactoring to consolidate the VFIO driver facing API
    to use vfio_device (Jason Gunthorpe)
 
  - Use drvdata to store vfio_device among all vfio-pci and variant
    drivers (Jason Gunthorpe)
 
  - Remove redundant code now that IOMMU core manages group DMA
    ownership (Jason Gunthorpe)
 
  - Remove vfio_group from external API handling struct file ownership
    (Jason Gunthorpe)
 
  - Correct typo in uapi comments (Thomas Huth)
 
  - Fix coccicheck detected deadlock (Wan Jiabing)
 
  - Use rwsem to remove races and simplify code around container and
    kvm association to groups (Jason Gunthorpe)
 
  - Harden access to devices in low power states and use runtime PM to
    enable d3cold support for unused devices (Abhishek Sahu)
 
  - Fix dma_owner handling of fake IOMMU groups (Jason Gunthorpe)
 
  - Set driver_managed_dma on vfio-pci variant drivers (Jason Gunthorpe)
 
  - Pass KVM pointer directly rather than via notifier (Matthew Rosato)
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Merge tag 'vfio-v5.19-rc1' of https://github.com/awilliam/linux-vfio

Pull vfio updates from Alex Williamson:

 - Improvements to mlx5 vfio-pci variant driver, including support for
   parallel migration per PF (Yishai Hadas)

 - Remove redundant iommu_present() check (Robin Murphy)

 - Ongoing refactoring to consolidate the VFIO driver facing API to use
   vfio_device (Jason Gunthorpe)

 - Use drvdata to store vfio_device among all vfio-pci and variant
   drivers (Jason Gunthorpe)

 - Remove redundant code now that IOMMU core manages group DMA ownership
   (Jason Gunthorpe)

 - Remove vfio_group from external API handling struct file ownership
   (Jason Gunthorpe)

 - Correct typo in uapi comments (Thomas Huth)

 - Fix coccicheck detected deadlock (Wan Jiabing)

 - Use rwsem to remove races and simplify code around container and kvm
   association to groups (Jason Gunthorpe)

 - Harden access to devices in low power states and use runtime PM to
   enable d3cold support for unused devices (Abhishek Sahu)

 - Fix dma_owner handling of fake IOMMU groups (Jason Gunthorpe)

 - Set driver_managed_dma on vfio-pci variant drivers (Jason Gunthorpe)

 - Pass KVM pointer directly rather than via notifier (Matthew Rosato)

* tag 'vfio-v5.19-rc1' of https://github.com/awilliam/linux-vfio: (38 commits)
  vfio: remove VFIO_GROUP_NOTIFY_SET_KVM
  vfio/pci: Add driver_managed_dma to the new vfio_pci drivers
  vfio: Do not manipulate iommu dma_owner for fake iommu groups
  vfio/pci: Move the unused device into low power state with runtime PM
  vfio/pci: Virtualize PME related registers bits and initialize to zero
  vfio/pci: Change the PF power state to D0 before enabling VFs
  vfio/pci: Invalidate mmaps and block the access in D3hot power state
  vfio: Change struct vfio_group::container_users to a non-atomic int
  vfio: Simplify the life cycle of the group FD
  vfio: Fully lock struct vfio_group::container
  vfio: Split up vfio_group_get_device_fd()
  vfio: Change struct vfio_group::opened from an atomic to bool
  vfio: Add missing locking for struct vfio_group::kvm
  kvm/vfio: Fix potential deadlock problem in vfio
  include/uapi/linux/vfio.h: Fix trivial typo - _IORW should be _IOWR instead
  vfio/pci: Use the struct file as the handle not the vfio_group
  kvm/vfio: Remove vfio_group from kvm
  vfio: Change vfio_group_set_kvm() to vfio_file_set_kvm()
  vfio: Change vfio_external_check_extension() to vfio_file_enforced_coherent()
  vfio: Remove vfio_external_group_match_file()
  ...
2022-06-01 13:49:15 -07:00
Linus Torvalds bf9095424d S390:
* ultravisor communication device driver
 
 * fix TEID on terminating storage key ops
 
 RISC-V:
 
 * Added Sv57x4 support for G-stage page table
 
 * Added range based local HFENCE functions
 
 * Added remote HFENCE functions based on VCPU requests
 
 * Added ISA extension registers in ONE_REG interface
 
 * Updated KVM RISC-V maintainers entry to cover selftests support
 
 ARM:
 
 * Add support for the ARMv8.6 WFxT extension
 
 * Guard pages for the EL2 stacks
 
 * Trap and emulate AArch32 ID registers to hide unsupported features
 
 * Ability to select and save/restore the set of hypercalls exposed
   to the guest
 
 * Support for PSCI-initiated suspend in collaboration with userspace
 
 * GICv3 register-based LPI invalidation support
 
 * Move host PMU event merging into the vcpu data structure
 
 * GICv3 ITS save/restore fixes
 
 * The usual set of small-scale cleanups and fixes
 
 x86:
 
 * New ioctls to get/set TSC frequency for a whole VM
 
 * Allow userspace to opt out of hypercall patching
 
 * Only do MSR filtering for MSRs accessed by rdmsr/wrmsr
 
 AMD SEV improvements:
 
 * Add KVM_EXIT_SHUTDOWN metadata for SEV-ES
 
 * V_TSC_AUX support
 
 Nested virtualization improvements for AMD:
 
 * Support for "nested nested" optimizations (nested vVMLOAD/VMSAVE,
   nested vGIF)
 
 * Allow AVIC to co-exist with a nested guest running
 
 * Fixes for LBR virtualizations when a nested guest is running,
   and nested LBR virtualization support
 
 * PAUSE filtering for nested hypervisors
 
 Guest support:
 
 * Decoupling of vcpu_is_preempted from PV spinlocks
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "S390:

   - ultravisor communication device driver

   - fix TEID on terminating storage key ops

  RISC-V:

   - Added Sv57x4 support for G-stage page table

   - Added range based local HFENCE functions

   - Added remote HFENCE functions based on VCPU requests

   - Added ISA extension registers in ONE_REG interface

   - Updated KVM RISC-V maintainers entry to cover selftests support

  ARM:

   - Add support for the ARMv8.6 WFxT extension

   - Guard pages for the EL2 stacks

   - Trap and emulate AArch32 ID registers to hide unsupported features

   - Ability to select and save/restore the set of hypercalls exposed to
     the guest

   - Support for PSCI-initiated suspend in collaboration with userspace

   - GICv3 register-based LPI invalidation support

   - Move host PMU event merging into the vcpu data structure

   - GICv3 ITS save/restore fixes

   - The usual set of small-scale cleanups and fixes

  x86:

   - New ioctls to get/set TSC frequency for a whole VM

   - Allow userspace to opt out of hypercall patching

   - Only do MSR filtering for MSRs accessed by rdmsr/wrmsr

  AMD SEV improvements:

   - Add KVM_EXIT_SHUTDOWN metadata for SEV-ES

   - V_TSC_AUX support

  Nested virtualization improvements for AMD:

   - Support for "nested nested" optimizations (nested vVMLOAD/VMSAVE,
     nested vGIF)

   - Allow AVIC to co-exist with a nested guest running

   - Fixes for LBR virtualizations when a nested guest is running, and
     nested LBR virtualization support

   - PAUSE filtering for nested hypervisors

  Guest support:

   - Decoupling of vcpu_is_preempted from PV spinlocks"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (199 commits)
  KVM: x86: Fix the intel_pt PMI handling wrongly considered from guest
  KVM: selftests: x86: Sync the new name of the test case to .gitignore
  Documentation: kvm: reorder ARM-specific section about KVM_SYSTEM_EVENT_SUSPEND
  x86, kvm: use correct GFP flags for preemption disabled
  KVM: LAPIC: Drop pending LAPIC timer injection when canceling the timer
  x86/kvm: Alloc dummy async #PF token outside of raw spinlock
  KVM: x86: avoid calling x86 emulator without a decoded instruction
  KVM: SVM: Use kzalloc for sev ioctl interfaces to prevent kernel data leak
  x86/fpu: KVM: Set the base guest FPU uABI size to sizeof(struct kvm_xsave)
  s390/uv_uapi: depend on CONFIG_S390
  KVM: selftests: x86: Fix test failure on arch lbr capable platforms
  KVM: LAPIC: Trace LAPIC timer expiration on every vmentry
  KVM: s390: selftest: Test suppression indication on key prot exception
  KVM: s390: Don't indicate suppression on dirtying, failing memop
  selftests: drivers/s390x: Add uvdevice tests
  drivers/s390/char: Add Ultravisor io device
  MAINTAINERS: Update KVM RISC-V entry to cover selftests support
  RISC-V: KVM: Introduce ISA extension register
  RISC-V: KVM: Cleanup stale TLB entries when host CPU changes
  RISC-V: KVM: Add remote HFENCE functions based on VCPU requests
  ...
2022-05-26 14:20:14 -07:00
Paolo Bonzini 47e8eec832 KVM/arm64 updates for 5.19
- Add support for the ARMv8.6 WFxT extension
 
 - Guard pages for the EL2 stacks
 
 - Trap and emulate AArch32 ID registers to hide unsupported features
 
 - Ability to select and save/restore the set of hypercalls exposed
   to the guest
 
 - Support for PSCI-initiated suspend in collaboration with userspace
 
 - GICv3 register-based LPI invalidation support
 
 - Move host PMU event merging into the vcpu data structure
 
 - GICv3 ITS save/restore fixes
 
 - The usual set of small-scale cleanups and fixes
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Merge tag 'kvmarm-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 5.19

- Add support for the ARMv8.6 WFxT extension

- Guard pages for the EL2 stacks

- Trap and emulate AArch32 ID registers to hide unsupported features

- Ability to select and save/restore the set of hypercalls exposed
  to the guest

- Support for PSCI-initiated suspend in collaboration with userspace

- GICv3 register-based LPI invalidation support

- Move host PMU event merging into the vcpu data structure

- GICv3 ITS save/restore fixes

- The usual set of small-scale cleanups and fixes

[Due to the conflict, KVM_SYSTEM_EVENT_SEV_TERM is relocated
 from 4 to 6. - Paolo]
2022-05-25 05:09:23 -04:00
Sean Christopherson c87661f855 KVM: Free new dirty bitmap if creating a new memslot fails
Fix a goof in kvm_prepare_memory_region() where KVM fails to free the
new memslot's dirty bitmap during a CREATE action if
kvm_arch_prepare_memory_region() fails.  The logic is supposed to detect
if the bitmap was allocated and thus needs to be freed, versus if the
bitmap was inherited from the old memslot and thus needs to be kept.  If
there is no old memslot, then obviously the bitmap can't have been
inherited

The bug was exposed by commit 86931ff720 ("KVM: x86/mmu: Do not create
SPTEs for GFNs that exceed host.MAXPHYADDR"), which made it trivally easy
for syzkaller to trigger failure during kvm_arch_prepare_memory_region(),
but the bug can be hit other ways too, e.g. due to -ENOMEM when
allocating x86's memslot metadata.

The backtrace from kmemleak:

  __vmalloc_node_range+0xb40/0xbd0 mm/vmalloc.c:3195
  __vmalloc_node mm/vmalloc.c:3232 [inline]
  __vmalloc+0x49/0x50 mm/vmalloc.c:3246
  __vmalloc_array mm/util.c:671 [inline]
  __vcalloc+0x49/0x70 mm/util.c:694
  kvm_alloc_dirty_bitmap virt/kvm/kvm_main.c:1319
  kvm_prepare_memory_region virt/kvm/kvm_main.c:1551
  kvm_set_memslot+0x1bd/0x690 virt/kvm/kvm_main.c:1782
  __kvm_set_memory_region+0x689/0x750 virt/kvm/kvm_main.c:1949
  kvm_set_memory_region virt/kvm/kvm_main.c:1962
  kvm_vm_ioctl_set_memory_region virt/kvm/kvm_main.c:1974
  kvm_vm_ioctl+0x377/0x13a0 virt/kvm/kvm_main.c:4528
  vfs_ioctl fs/ioctl.c:51
  __do_sys_ioctl fs/ioctl.c:870
  __se_sys_ioctl fs/ioctl.c:856
  __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
  do_syscall_x64 arch/x86/entry/common.c:50
  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

And the relevant sequence of KVM events:

  ioctl(3, KVM_CREATE_VM, 0)              = 4
  ioctl(4, KVM_SET_USER_MEMORY_REGION, {slot=0,
                                        flags=KVM_MEM_LOG_DIRTY_PAGES,
                                        guest_phys_addr=0x10000000000000,
                                        memory_size=4096,
                                        userspace_addr=0x20fe8000}
       ) = -1 EINVAL (Invalid argument)

Fixes: 244893fa28 ("KVM: Dynamically allocate "new" memslots from the get-go")
Cc: stable@vger.kernel.org
Reported-by: syzbot+8606b8a9cc97a63f1c87@syzkaller.appspotmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220518003842.1341782-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-20 13:02:05 -04:00
Wanpeng Li e332b55fe7 KVM: eventfd: Fix false positive RCU usage warning
The splat below can be seen when running kvm-unit-test:

     =============================
     WARNING: suspicious RCU usage
     5.18.0-rc7 #5 Tainted: G          IOE
     -----------------------------
     /home/kernel/linux/arch/x86/kvm/../../../virt/kvm/eventfd.c:80 RCU-list traversed in non-reader section!!

     other info that might help us debug this:

     rcu_scheduler_active = 2, debug_locks = 1
     4 locks held by qemu-system-x86/35124:
      #0: ffff9725391d80b8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x77/0x710 [kvm]
      #1: ffffbd25cfb2a0b8 (&kvm->srcu){....}-{0:0}, at: vcpu_enter_guest+0xdeb/0x1900 [kvm]
      #2: ffffbd25cfb2b920 (&kvm->irq_srcu){....}-{0:0}, at: kvm_hv_notify_acked_sint+0x79/0x1e0 [kvm]
      #3: ffffbd25cfb2b920 (&kvm->irq_srcu){....}-{0:0}, at: irqfd_resampler_ack+0x5/0x110 [kvm]

     stack backtrace:
     CPU: 2 PID: 35124 Comm: qemu-system-x86 Tainted: G          IOE     5.18.0-rc7 #5
     Call Trace:
      <TASK>
      dump_stack_lvl+0x6c/0x9b
      irqfd_resampler_ack+0xfd/0x110 [kvm]
      kvm_notify_acked_gsi+0x32/0x90 [kvm]
      kvm_hv_notify_acked_sint+0xc5/0x1e0 [kvm]
      kvm_hv_set_msr_common+0xec1/0x1160 [kvm]
      kvm_set_msr_common+0x7c3/0xf60 [kvm]
      vmx_set_msr+0x394/0x1240 [kvm_intel]
      kvm_set_msr_ignored_check+0x86/0x200 [kvm]
      kvm_emulate_wrmsr+0x4f/0x1f0 [kvm]
      vmx_handle_exit+0x6fb/0x7e0 [kvm_intel]
      vcpu_enter_guest+0xe5a/0x1900 [kvm]
      kvm_arch_vcpu_ioctl_run+0x16e/0xac0 [kvm]
      kvm_vcpu_ioctl+0x279/0x710 [kvm]
      __x64_sys_ioctl+0x83/0xb0
      do_syscall_64+0x3b/0x90
      entry_SYSCALL_64_after_hwframe+0x44/0xae

resampler-list is protected by irq_srcu (see kvm_irqfd_assign), so fix
the false positive by using list_for_each_entry_srcu().

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1652950153-12489-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-20 09:10:33 -04:00
Wan Jiabing 6b17ca8e5e kvm/vfio: Fix potential deadlock problem in vfio
Fix following coccicheck warning:
./virt/kvm/vfio.c:258:1-7: preceding lock on line 236

If kvm_vfio_file_iommu_group() failed, code would goto err_fdput with
mutex_lock acquired and then return ret. It might cause potential
deadlock. Move mutex_unlock bellow err_fdput tag to fix it.

Fixes: d55d9e7a45 ("kvm/vfio: Store the struct file in the kvm_vfio_group")
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20220517023441.4258-1-wanjiabing@vivo.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-05-17 13:07:09 -06:00
Jason Gunthorpe 3e5449d5f9 kvm/vfio: Remove vfio_group from kvm
None of the VFIO APIs take in the vfio_group anymore, so we can remove it
completely.

This has a subtle side effect on the enforced coherency tracking. The
vfio_group_get_external_user() was holding on to the container_users which
would prevent the iommu_domain and thus the enforced coherency value from
changing while the group is registered with kvm.

It changes the security proof slightly into 'user must hold a group FD
that has a device that cannot enforce DMA coherence'. As opening the group
FD, not attaching the container, is the privileged operation this doesn't
change the security properties much.

On the flip side it paves the way to changing the iommu_domain/container
attached to a group at runtime which is something that will be required to
support nested translation.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>i
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/7-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-05-13 10:14:20 -06:00
Jason Gunthorpe ba70a89f3c vfio: Change vfio_group_set_kvm() to vfio_file_set_kvm()
Just change the argument from struct vfio_group to struct file *.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/6-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-05-13 10:14:20 -06:00
Jason Gunthorpe a905ad043f vfio: Change vfio_external_check_extension() to vfio_file_enforced_coherent()
Instead of a general extension check change the function into a limited
test if the iommu_domain has enforced coherency, which is the only thing
kvm needs to query.

Make the new op self contained by properly refcounting the container
before touching it.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/5-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-05-13 10:14:20 -06:00
Jason Gunthorpe c38ff5b0c3 vfio: Remove vfio_external_group_match_file()
vfio_group_fops_open() ensures there is only ever one struct file open for
any struct vfio_group at any time:

	/* Do we need multiple instances of the group open?  Seems not. */
	opened = atomic_cmpxchg(&group->opened, 0, 1);
	if (opened) {
		vfio_group_put(group);
		return -EBUSY;

Therefor the struct file * can be used directly to search the list of VFIO
groups that KVM keeps instead of using the
vfio_external_group_match_file() callback to try to figure out if the
passed in FD matches the list or not.

Delete vfio_external_group_match_file().

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/4-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-05-13 10:14:19 -06:00
Jason Gunthorpe 50d63b5bbf vfio: Change vfio_external_user_iommu_id() to vfio_file_iommu_group()
The only caller wants to get a pointer to the struct iommu_group
associated with the VFIO group file. Instead of returning the group ID
then searching sysfs for that string to get the struct iommu_group just
directly return the iommu_group pointer already held by the vfio_group
struct.

It already has a safe lifetime due to the struct file kref, the vfio_group
and thus the iommu_group cannot be destroyed while the group file is open.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-05-13 10:14:19 -06:00
Jason Gunthorpe d55d9e7a45 kvm/vfio: Store the struct file in the kvm_vfio_group
Following patches will change the APIs to use the struct file as the handle
instead of the vfio_group, so hang on to a reference to it with the same
duration of as the vfio_group.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/2-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-05-13 10:14:19 -06:00
Jason Gunthorpe 73b0565f19 kvm/vfio: Move KVM_DEV_VFIO_GROUP_* ioctls into functions
To make it easier to read and change in following patches.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/1-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-05-13 10:14:19 -06:00
Sean Christopherson f502cc568d KVM: Add max_vcpus field in common 'struct kvm'
For TDX guests, the maximum number of vcpus needs to be specified when the
TDX guest VM is initialized (creating the TDX data corresponding to TDX
guest) before creating vcpu.  It needs to record the maximum number of
vcpus on VM creation (KVM_CREATE_VM) and return error if the number of
vcpus exceeds it

Because there is already max_vcpu member in arm64 struct kvm_arch, move it
to common struct kvm and initialize it to KVM_MAX_VCPUS before
kvm_arch_init_vm() instead of adding it to x86 struct kvm_arch.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Message-Id: <e53234cdee6a92357d06c80c03d77c19cdefb804.1646422845.git.isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-02 11:42:42 -04:00
Paolo Bonzini 73331c5d84 Merge branch 'kvm-fixes-for-5.18-rc5' into HEAD
Fixes for (relatively) old bugs, to be merged in both the -rc and next
development trees:

* Fix potential races when walking host page table

* Fix bad user ABI for KVM_EXIT_SYSTEM_EVENT

* Fix shadow page table leak when KVM runs nested
2022-04-29 12:39:34 -04:00
Paolo Bonzini d495f942f4 KVM: fix bad user ABI for KVM_EXIT_SYSTEM_EVENT
When KVM_EXIT_SYSTEM_EVENT was introduced, it included a flags
member that at the time was unused.  Unfortunately this extensibility
mechanism has several issues:

- x86 is not writing the member, so it would not be possible to use it
  on x86 except for new events

- the member is not aligned to 64 bits, so the definition of the
  uAPI struct is incorrect for 32- on 64-bit userspace.  This is a
  problem for RISC-V, which supports CONFIG_KVM_COMPAT, but fortunately
  usage of flags was only introduced in 5.18.

Since padding has to be introduced, place a new field in there
that tells if the flags field is valid.  To allow further extensibility,
in fact, change flags to an array of 16 values, and store how many
of the values are valid.  The availability of the new ndata field
is tied to a system capability; all architectures are changed to
fill in the field.

To avoid breaking compilation of userspace that was using the flags
field, provide a userspace-only union to overlap flags with data[0].
The new field is placed at the same offset for both 32- and 64-bit
userspace.

Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Peter Gonda <pgonda@google.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Message-Id: <20220422103013.34832-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-29 12:38:22 -04:00
Mingwei Zhang 683412ccf6 KVM: SEV: add cache flush to solve SEV cache incoherency issues
Flush the CPU caches when memory is reclaimed from an SEV guest (where
reclaim also includes it being unmapped from KVM's memslots).  Due to lack
of coherency for SEV encrypted memory, failure to flush results in silent
data corruption if userspace is malicious/broken and doesn't ensure SEV
guest memory is properly pinned and unpinned.

Cache coherency is not enforced across the VM boundary in SEV (AMD APM
vol.2 Section 15.34.7). Confidential cachelines, generated by confidential
VM guests have to be explicitly flushed on the host side. If a memory page
containing dirty confidential cachelines was released by VM and reallocated
to another user, the cachelines may corrupt the new user at a later time.

KVM takes a shortcut by assuming all confidential memory remain pinned
until the end of VM lifetime. Therefore, KVM does not flush cache at
mmu_notifier invalidation events. Because of this incorrect assumption and
the lack of cache flushing, malicous userspace can crash the host kernel:
creating a malicious VM and continuously allocates/releases unpinned
confidential memory pages when the VM is running.

Add cache flush operations to mmu_notifier operations to ensure that any
physical memory leaving the guest VM get flushed. In particular, hook
mmu_notifier_invalidate_range_start and mmu_notifier_release events and
flush cache accordingly. The hook after releasing the mmu lock to avoid
contention with other vCPUs.

Cc: stable@vger.kernel.org
Suggested-by: Sean Christpherson <seanjc@google.com>
Reported-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Message-Id: <20220421031407.2516575-4-mizhang@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-21 15:41:00 -04:00
Tom Rix a413a625b4 KVM: SPDX style and spelling fixes
SPDX comments use use /* */ style comments in headers anad
// style comments in .c files.  Also fix two spelling mistakes.

Signed-off-by: Tom Rix <trix@redhat.com>
Message-Id: <20220410153840.55506-1-trix@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-21 13:16:13 -04:00
Sean Christopherson 5c697c367a KVM: Initialize debugfs_dentry when a VM is created to avoid NULL deref
Initialize debugfs_entry to its semi-magical -ENOENT value when the VM
is created.  KVM's teardown when VM creation fails is kludgy and calls
kvm_uevent_notify_change() and kvm_destroy_vm_debugfs() even if KVM never
attempted kvm_create_vm_debugfs().  Because debugfs_entry is zero
initialized, the IS_ERR() checks pass and KVM derefs a NULL pointer.

  BUG: kernel NULL pointer dereference, address: 0000000000000018
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 1068b1067 P4D 1068b1067 PUD 1068b0067 PMD 0
  Oops: 0000 [#1] SMP
  CPU: 0 PID: 871 Comm: repro Not tainted 5.18.0-rc1+ #825
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:__dentry_path+0x7b/0x130
  Call Trace:
   <TASK>
   dentry_path_raw+0x42/0x70
   kvm_uevent_notify_change.part.0+0x10c/0x200 [kvm]
   kvm_put_kvm+0x63/0x2b0 [kvm]
   kvm_dev_ioctl+0x43a/0x920 [kvm]
   __x64_sys_ioctl+0x83/0xb0
   do_syscall_64+0x31/0x50
   entry_SYSCALL_64_after_hwframe+0x44/0xae
   </TASK>
  Modules linked in: kvm_intel kvm irqbypass

Fixes: a44a4cc1c9 ("KVM: Don't create VM debugfs files outside of the VM directory")
Cc: stable@vger.kernel.org
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oupton@google.com>
Reported-by: syzbot+df6fbbd2ee39f21289ef@syzkaller.appspotmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Message-Id: <20220415004622.2207751-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-21 13:16:11 -04:00
Paolo Bonzini a44e2c207c KVM/arm64 fixes for 5.18, take #1
- Some PSCI fixes after introducing PSCIv1.1 and SYSTEM_RESET2
 
 - Fix the MMU write-lock not being taken on THP split
 
 - Fix mixed-width VM handling
 
 - Fix potential UAF when debugfs registration fails
 
 - Various selftest updates for all of the above
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Merge tag 'kvmarm-fixes-5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 5.18, take #1

- Some PSCI fixes after introducing PSCIv1.1 and SYSTEM_RESET2

- Fix the MMU write-lock not being taken on THP split

- Fix mixed-width VM handling

- Fix potential UAF when debugfs registration fails

- Various selftest updates for all of the above
2022-04-08 12:30:04 -04:00
Oliver Upton a44a4cc1c9 KVM: Don't create VM debugfs files outside of the VM directory
Unfortunately, there is no guarantee that KVM was able to instantiate a
debugfs directory for a particular VM. To that end, KVM shouldn't even
attempt to create new debugfs files in this case. If the specified
parent dentry is NULL, debugfs_create_file() will instantiate files at
the root of debugfs.

For arm64, it is possible to create the vgic-state file outside of a
VM directory, the file is not cleaned up when a VM is destroyed.
Nonetheless, the corresponding struct kvm is freed when the VM is
destroyed.

Nip the problem in the bud for all possible errant debugfs file
creations by initializing kvm->debugfs_dentry to -ENOENT. In so doing,
debugfs_create_file() will fail instead of creating the file in the root
directory.

Cc: stable@kernel.org
Fixes: 929f45e324 ("kvm: no need to check return value of debugfs_create functions")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220406235615.1447180-2-oupton@google.com
2022-04-07 08:46:13 +01:00
Paolo Bonzini 5593473a1e KVM: avoid NULL pointer dereference in kvm_dirty_ring_push
kvm_vcpu_release() will call kvm_dirty_ring_free(), freeing
ring->dirty_gfns and setting it to NULL.  Afterwards, it calls
kvm_arch_vcpu_destroy().

However, if closing the file descriptor races with KVM_RUN in such away
that vcpu->arch.st.preempted == 0, the following call stack leads to a
NULL pointer dereference in kvm_dirty_run_push():

 mark_page_dirty_in_slot+0x192/0x270 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3171
 kvm_steal_time_set_preempted arch/x86/kvm/x86.c:4600 [inline]
 kvm_arch_vcpu_put+0x34e/0x5b0 arch/x86/kvm/x86.c:4618
 vcpu_put+0x1b/0x70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:211
 vmx_free_vcpu+0xcb/0x130 arch/x86/kvm/vmx/vmx.c:6985
 kvm_arch_vcpu_destroy+0x76/0x290 arch/x86/kvm/x86.c:11219
 kvm_vcpu_destroy arch/x86/kvm/../../../virt/kvm/kvm_main.c:441 [inline]

The fix is to release the dirty page ring after kvm_arch_vcpu_destroy
has run.

Reported-by: Qiuhao Li <qiuhao@sysec.org>
Reported-by: Gaoning Pan <pgn@zju.edu.cn>
Reported-by: Yongkang Jia <kangel@zju.edu.cn>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-06 13:26:30 -04:00
David Woodhouse cf1d88b36b KVM: Remove dirty handling from gfn_to_pfn_cache completely
It isn't OK to cache the dirty status of a page in internal structures
for an indefinite period of time.

Any time a vCPU exits the run loop to userspace might be its last; the
VMM might do its final check of the dirty log, flush the last remaining
dirty pages to the destination and complete a live migration. If we
have internal 'dirty' state which doesn't get flushed until the vCPU
is finally destroyed on the source after migration is complete, then
we have lost data because that will escape the final copy.

This problem already exists with the use of kvm_vcpu_unmap() to mark
pages dirty in e.g. VMX nesting.

Note that the actual Linux MM already considers the page to be dirty
since we have a writeable mapping of it. This is just about the KVM
dirty logging.

For the nesting-style use cases (KVM_GUEST_USES_PFN) we will need to
track which gfn_to_pfn_caches have been used and explicitly mark the
corresponding pages dirty before returning to userspace. But we would
have needed external tracking of that anyway, rather than walking the
full list of GPCs to find those belonging to this vCPU which are dirty.

So let's rely *solely* on that external tracking, and keep it simple
rather than laying a tempting trap for callers to fall into.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220303154127.202856-3-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-02 05:34:41 -04:00
Sean Christopherson d0d96121d0 KVM: Use enum to track if cached PFN will be used in guest and/or host
Replace the guest_uses_pa and kernel_map booleans in the PFN cache code
with a unified enum/bitmask. Using explicit names makes it easier to
review and audit call sites.

Opportunistically add a WARN to prevent passing garbage; instantating a
cache without declaring its usage is either buggy or pointless.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220303154127.202856-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-02 05:34:41 -04:00
Sean Christopherson df06dae3f2 KVM: Don't actually set a request when evicting vCPUs for GFN cache invd
Don't actually set a request bit in vcpu->requests when making a request
purely to force a vCPU to exit the guest.  Logging a request but not
actually consuming it would cause the vCPU to get stuck in an infinite
loop during KVM_RUN because KVM would see the pending request and bail
from VM-Enter to service the request.

Note, it's currently impossible for KVM to set KVM_REQ_GPC_INVALIDATE as
nothing in KVM is wired up to set guest_uses_pa=true.  But, it'd be all
too easy for arch code to introduce use of kvm_gfn_to_pfn_cache_init()
without implementing handling of the request, especially since getting
test coverage of MMU notifier interaction with specific KVM features
usually requires a directed test.

Opportunistically rename gfn_to_pfn_cache_invalidate_start()'s wake_vcpus
to evict_vcpus.  The purpose of the request is to get vCPUs out of guest
mode, it's supposed to _avoid_ waking vCPUs that are blocking.

Opportunistically rename KVM_REQ_GPC_INVALIDATE to be more specific as to
what it wants to accomplish, and to genericize the name so that it can
used for similar but unrelated scenarios, should they arise in the future.
Add a comment and documentation to explain why the "no action" request
exists.

Add compile-time assertions to help detect improper usage.  Use the inner
assertless helper in the one s390 path that makes requests without a
hardcoded request.

Cc: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220223165302.3205276-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-02 05:34:39 -04:00
David Woodhouse 79593c086e KVM: avoid double put_page with gfn-to-pfn cache
If the cache's user host virtual address becomes invalid, there
is still a path from kvm_gfn_to_pfn_cache_refresh() where __release_gpc()
could release the pfn but the gpc->pfn field has not been overwritten
with an error value.  If this happens, kvm_gfn_to_pfn_cache_unmap will
call put_page again on the same page.

Cc: stable@vger.kernel.org
Fixes: 982ed0de47 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support")
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-02 05:34:39 -04:00
David Matlack 70375c2d8f Revert "KVM: set owner of cpu and vm file operations"
This reverts commit 3d3aab1b97.

Now that the KVM module's lifetime is tied to kvm.users_count, there is
no need to also tie it's lifetime to the lifetime of the VM and vCPU
file descriptors.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220303183328.1499189-3-dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-29 13:02:25 -04:00
David Matlack 5f6de5cbeb KVM: Prevent module exit until all VMs are freed
Tie the lifetime the KVM module to the lifetime of each VM via
kvm.users_count. This way anything that grabs a reference to the VM via
kvm_get_kvm() cannot accidentally outlive the KVM module.

Prior to this commit, the lifetime of the KVM module was tied to the
lifetime of /dev/kvm file descriptors, VM file descriptors, and vCPU
file descriptors by their respective file_operations "owner" field.
This approach is insufficient because references grabbed via
kvm_get_kvm() do not prevent closing any of the aforementioned file
descriptors.

This fixes a long standing theoretical bug in KVM that at least affects
async page faults. kvm_setup_async_pf() grabs a reference via
kvm_get_kvm(), and drops it in an asynchronous work callback. Nothing
prevents the VM file descriptor from being closed and the KVM module
from being unloaded before this callback runs.

Fixes: af585b921e ("KVM: Halt vcpu if page it tries to access is swapped out")
Fixes: 3d3aab1b97 ("KVM: set owner of cpu and vm file operations")
Cc: stable@vger.kernel.org
Suggested-by: Ben Gardon <bgardon@google.com>
[ Based on a patch from Ben implemented for Google's kernel. ]
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220303183328.1499189-2-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-29 13:02:25 -04:00
Guo Ren afec0c65d0 KVM: compat: riscv: Prevent KVM_COMPAT from being selected
Current riscv doesn't support the 32bit KVM API. Let's make it
clear by not selecting KVM_COMPAT.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Anup Patel <anup@brainfault.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Anup Patel <anup@brainfault.org>
2022-03-11 19:02:15 +05:30
Paolo Bonzini 37b2a6510a KVM: use __vcalloc for very large allocations
Allocations whose size is related to the memslot size can be arbitrarily
large.  Do not use kvzalloc/kvcalloc, as those are limited to "not crazy"
sizes that fit in 32 bits.

Cc: stable@vger.kernel.org
Fixes: 7661809d49 ("mm: don't allow oversized kvmalloc() calls")
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-08 09:30:57 -05:00
Paolo Bonzini 0564eeb71b Merge branch 'kvm-bugfixes' into HEAD
Merge bugfixes from 5.17 before merging more tricky work.
2022-03-04 18:39:29 -05:00
Sean Christopherson 2f6f66ccd2 KVM: Drop kvm_reload_remote_mmus(), open code request in x86 users
Remove the generic kvm_reload_remote_mmus() and open code its
functionality into the two x86 callers.  x86 is (obviously) the only
architecture that uses the hook, and is also the only architecture that
uses KVM_REQ_MMU_RELOAD in a way that's consistent with the name.  That
will change in a future patch, as x86's usage when zapping a single
shadow page x86 doesn't actually _need_ to reload all vCPUs' MMUs, only
MMUs whose root is being zapped actually need to be reloaded.

s390 also uses KVM_REQ_MMU_RELOAD, but for a slightly different purpose.

Drop the generic code in anticipation of implementing s390 and x86 arch
specific requests, which will allow dropping KVM_REQ_MMU_RELOAD entirely.

Opportunistically reword the x86 TDP MMU comment to avoid making
references to functions (and requests!) when possible, and to remove the
rather ambiguous "this".

No functional change intended.

Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220225182248.3812651-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-01 08:58:25 -05:00
Vipin Sharma e45cce30ea KVM: Move VM's worker kthreads back to the original cgroup before exiting.
VM worker kthreads can linger in the VM process's cgroup for sometime
after KVM terminates the VM process.

KVM terminates the worker kthreads by calling kthread_stop() which waits
on the 'exited' completion, triggered by exit_mm(), via mm_release(), in
do_exit() during the kthread's exit.  However, these kthreads are
removed from the cgroup using the cgroup_exit() which happens after the
exit_mm(). Therefore, A VM process can terminate in between the
exit_mm() and cgroup_exit() calls, leaving only worker kthreads in the
cgroup.

Moving worker kthreads back to the original cgroup (kthreadd_task's
cgroup) makes sure that the cgroup is empty as soon as the main VM
process is terminated.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220222054848.563321-1-vipinsh@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-25 08:20:14 -05:00
Wanpeng Li 4cb9a998b1 KVM: Fix lockdep false negative during host resume
I saw the below splatting after the host suspended and resumed.

   WARNING: CPU: 0 PID: 2943 at kvm/arch/x86/kvm/../../../virt/kvm/kvm_main.c:5531 kvm_resume+0x2c/0x30 [kvm]
   CPU: 0 PID: 2943 Comm: step_after_susp Tainted: G        W IOE     5.17.0-rc3+ #4
   RIP: 0010:kvm_resume+0x2c/0x30 [kvm]
   Call Trace:
    <TASK>
    syscore_resume+0x90/0x340
    suspend_devices_and_enter+0xaee/0xe90
    pm_suspend.cold+0x36b/0x3c2
    state_store+0x82/0xf0
    kernfs_fop_write_iter+0x1b6/0x260
    new_sync_write+0x258/0x370
    vfs_write+0x33f/0x510
    ksys_write+0xc9/0x160
    do_syscall_64+0x3b/0xc0
    entry_SYSCALL_64_after_hwframe+0x44/0xae

lockdep_is_held() can return -1 when lockdep is disabled which triggers
this warning. Let's use lockdep_assert_not_held() which can detect
incorrect calls while holding a lock and it also avoids false negatives
when lockdep is disabled.

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1644920142-81249-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-17 09:52:50 -05:00
Jinrong Liang b56bd8e03c KVM: Remove unused "kvm" of kvm_make_vcpu_request()
The "struct kvm *kvm" parameter of kvm_make_vcpu_request() is not used,
so remove it. No functional change intended.

Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Message-Id: <20220125095909.38122-19-cloudliang@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10 13:47:15 -05:00
Linus Torvalds 3cd7cd8a62 Two larger x86 series:
* Redo incorrect fix for SEV/SMAP erratum
 
 * Windows 11 Hyper-V workaround
 
 Other x86 changes:
 
 * Various x86 cleanups
 
 * Re-enable access_tracking_perf_test
 
 * Fix for #GP handling on SVM
 
 * Fix for CPUID leaf 0Dh in KVM_GET_SUPPORTED_CPUID
 
 * Fix for ICEBP in interrupt shadow
 
 * Avoid false-positive RCU splat
 
 * Enable Enlightened MSR-Bitmap support for real
 
 ARM:
 
 * Correctly update the shadow register on exception injection when
 running in nVHE mode
 
 * Correctly use the mm_ops indirection when performing cache invalidation
 from the page-table walker
 
 * Restrict the vgic-v3 workaround for SEIS to the two known broken
 implementations
 
 Generic code changes:
 
 * Dead code cleanup
 
 There will be another pull request for ARM fixes next week, but
 those patches need a bit more soak time.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "Two larger x86 series:

   - Redo incorrect fix for SEV/SMAP erratum

   - Windows 11 Hyper-V workaround

  Other x86 changes:

   - Various x86 cleanups

   - Re-enable access_tracking_perf_test

   - Fix for #GP handling on SVM

   - Fix for CPUID leaf 0Dh in KVM_GET_SUPPORTED_CPUID

   - Fix for ICEBP in interrupt shadow

   - Avoid false-positive RCU splat

   - Enable Enlightened MSR-Bitmap support for real

  ARM:

   - Correctly update the shadow register on exception injection when
     running in nVHE mode

   - Correctly use the mm_ops indirection when performing cache
     invalidation from the page-table walker

   - Restrict the vgic-v3 workaround for SEIS to the two known broken
     implementations

  Generic code changes:

   - Dead code cleanup"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (43 commits)
  KVM: eventfd: Fix false positive RCU usage warning
  KVM: nVMX: Allow VMREAD when Enlightened VMCS is in use
  KVM: nVMX: Implement evmcs_field_offset() suitable for handle_vmread()
  KVM: nVMX: Rename vmcs_to_field_offset{,_table}
  KVM: nVMX: eVMCS: Filter out VM_EXIT_SAVE_VMX_PREEMPTION_TIMER
  KVM: nVMX: Also filter MSR_IA32_VMX_TRUE_PINBASED_CTLS when eVMCS
  selftests: kvm: check dynamic bits against KVM_X86_XCOMP_GUEST_SUPP
  KVM: x86: add system attribute to retrieve full set of supported xsave states
  KVM: x86: Add a helper to retrieve userspace address from kvm_device_attr
  selftests: kvm: move vm_xsave_req_perm call to amx_test
  KVM: x86: Sync the states size with the XCR0/IA32_XSS at, any time
  KVM: x86: Update vCPU's runtime CPUID on write to MSR_IA32_XSS
  KVM: x86: Keep MSR_IA32_XSS unchanged for INIT
  KVM: x86: Free kvm_cpuid_entry2 array on post-KVM_RUN KVM_SET_CPUID{,2}
  KVM: nVMX: WARN on any attempt to allocate shadow VMCS for vmcs02
  KVM: selftests: Don't skip L2's VMCALL in SMM test for SVM guest
  KVM: x86: Check .flags in kvm_cpuid_check_equal() too
  KVM: x86: Forcibly leave nested virt when SMM state is toggled
  KVM: SVM: drop unnecessary code in svm_hv_vmcb_dirty_nested_enlightenments()
  KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real
  ...
2022-01-28 19:00:26 +02:00
Hou Wenlong 6a0c61703e KVM: eventfd: Fix false positive RCU usage warning
Fix the following false positive warning:
 =============================
 WARNING: suspicious RCU usage
 5.16.0-rc4+ #57 Not tainted
 -----------------------------
 arch/x86/kvm/../../../virt/kvm/eventfd.c:484 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 3 locks held by fc_vcpu 0/330:
  #0: ffff8884835fc0b0 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x88/0x6f0 [kvm]
  #1: ffffc90004c0bb68 (&kvm->srcu){....}-{0:0}, at: vcpu_enter_guest+0x600/0x1860 [kvm]
  #2: ffffc90004c0c1d0 (&kvm->irq_srcu){....}-{0:0}, at: kvm_notify_acked_irq+0x36/0x180 [kvm]

 stack backtrace:
 CPU: 26 PID: 330 Comm: fc_vcpu 0 Not tainted 5.16.0-rc4+
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x44/0x57
  kvm_notify_acked_gsi+0x6b/0x70 [kvm]
  kvm_notify_acked_irq+0x8d/0x180 [kvm]
  kvm_ioapic_update_eoi+0x92/0x240 [kvm]
  kvm_apic_set_eoi_accelerated+0x2a/0xe0 [kvm]
  handle_apic_eoi_induced+0x3d/0x60 [kvm_intel]
  vmx_handle_exit+0x19c/0x6a0 [kvm_intel]
  vcpu_enter_guest+0x66e/0x1860 [kvm]
  kvm_arch_vcpu_ioctl_run+0x438/0x7f0 [kvm]
  kvm_vcpu_ioctl+0x38a/0x6f0 [kvm]
  __x64_sys_ioctl+0x89/0xc0
  do_syscall_64+0x3a/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Since kvm_unregister_irq_ack_notifier() does synchronize_srcu(&kvm->irq_srcu),
kvm->irq_ack_notifier_list is protected by kvm->irq_srcu. In fact,
kvm->irq_srcu SRCU read lock is held in kvm_notify_acked_irq(), making it
a false positive warning. So use hlist_for_each_entry_srcu() instead of
hlist_for_each_entry_rcu().

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
Message-Id: <f98bac4f5052bad2c26df9ad50f7019e40434512.1643265976.git.houwenlong.hwl@antgroup.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-28 07:38:27 -05:00
Sean Christopherson 31c2558569 Revert "KVM: SVM: avoid infinite loop on NPF from bad address"
Revert a completely broken check on an "invalid" RIP in SVM's workaround
for the DecodeAssists SMAP errata.  kvm_vcpu_gfn_to_memslot() obviously
expects a gfn, i.e. operates in the guest physical address space, whereas
RIP is a virtual (not even linear) address.  The "fix" worked for the
problematic KVM selftest because the test identity mapped RIP.

Fully revert the hack instead of trying to translate RIP to a GPA, as the
non-SEV case is now handled earlier, and KVM cannot access guest page
tables to translate RIP.

This reverts commit e72436bc3a.

Fixes: e72436bc3a ("KVM: SVM: avoid infinite loop on NPF from bad address")
Reported-by: Liam Merwick <liam.merwick@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Message-Id: <20220120010719.711476-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-26 12:14:59 -05:00
Xianting Tian 1625566ec8 KVM: remove async parameter of hva_to_pfn_remapped()
The async parameter of hva_to_pfn_remapped() is not used, so remove it.

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Message-Id: <20220124020456.156386-1-xianting.tian@linux.alibaba.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-24 08:53:37 -05:00
Linus Torvalds 636b5284d8 Generic:
- selftest compilation fix for non-x86
 
 - KVM: avoid warning on s390 in mark_page_dirty
 
 x86:
 - fix page write-protection bug and improve comments
 
 - use binary search to lookup the PMU event filter, add test
 
 - enable_pmu module parameter support for Intel CPUs
 
 - switch blocked_vcpu_on_cpu_lock to raw spinlock
 
 - cleanups of blocked vCPU logic
 
 - partially allow KVM_SET_CPUID{,2} after KVM_RUN (5.16 regression)
 
 - various small fixes
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull more kvm updates from Paolo Bonzini:
 "Generic:

   - selftest compilation fix for non-x86

   - KVM: avoid warning on s390 in mark_page_dirty

 x86:

   - fix page write-protection bug and improve comments

   - use binary search to lookup the PMU event filter, add test

   - enable_pmu module parameter support for Intel CPUs

   - switch blocked_vcpu_on_cpu_lock to raw spinlock

   - cleanups of blocked vCPU logic

   - partially allow KVM_SET_CPUID{,2} after KVM_RUN (5.16 regression)

   - various small fixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (46 commits)
  docs: kvm: fix WARNINGs from api.rst
  selftests: kvm/x86: Fix the warning in lib/x86_64/processor.c
  selftests: kvm/x86: Fix the warning in pmu_event_filter_test.c
  kvm: selftests: Do not indent with spaces
  kvm: selftests: sync uapi/linux/kvm.h with Linux header
  selftests: kvm: add amx_test to .gitignore
  KVM: SVM: Nullify vcpu_(un)blocking() hooks if AVIC is disabled
  KVM: SVM: Move svm_hardware_setup() and its helpers below svm_x86_ops
  KVM: SVM: Drop AVIC's intermediate avic_set_running() helper
  KVM: VMX: Don't do full kick when handling posted interrupt wakeup
  KVM: VMX: Fold fallback path into triggering posted IRQ helper
  KVM: VMX: Pass desired vector instead of bool for triggering posted IRQ
  KVM: VMX: Don't do full kick when triggering posted interrupt "fails"
  KVM: SVM: Skip AVIC and IRTE updates when loading blocking vCPU
  KVM: SVM: Use kvm_vcpu_is_blocking() in AVIC load to handle preemption
  KVM: SVM: Remove unnecessary APICv/AVIC update in vCPU unblocking path
  KVM: SVM: Don't bother checking for "running" AVIC when kicking for IPIs
  KVM: SVM: Signal AVIC doorbell iff vCPU is in guest mode
  KVM: x86: Remove defunct pre_block/post_block kvm_x86_ops hooks
  KVM: x86: Unexport LAPIC's switch_to_{hv,sw}_timer() helpers
  ...
2022-01-22 09:40:01 +02:00
Sean Christopherson 12a8eee568 KVM: Move x86 VMX's posted interrupt list_head to vcpu_vmx
Move the seemingly generic block_vcpu_list from kvm_vcpu to vcpu_vmx, and
rename the list and all associated variables to clarify that it tracks
the set of vCPU that need to be poked on a posted interrupt to the wakeup
vector.  The list is not used to track _all_ vCPUs that are blocking, and
the term "blocked" can be misleading as it may refer to a blocking
condition in the host or the guest, where as the PI wakeup case is
specifically for the vCPUs that are actively blocking from within the
guest.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211208015236.1616697-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19 12:14:38 -05:00
Sean Christopherson e6eec09b7b KVM: Drop unused kvm_vcpu.pre_pcpu field
Remove kvm_vcpu.pre_pcpu as it no longer has any users.  No functional
change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211208015236.1616697-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19 12:14:37 -05:00
Christian Borntraeger e09fccb543 KVM: avoid warning on s390 in mark_page_dirty
Avoid warnings on s390 like
[ 1801.980931] CPU: 12 PID: 117600 Comm: kworker/12:0 Tainted: G            E     5.17.0-20220113.rc0.git0.32ce2abb03cf.300.fc35.s390x+next #1
[ 1801.980938] Workqueue: events irqfd_inject [kvm]
[...]
[ 1801.981057] Call Trace:
[ 1801.981060]  [<000003ff805f0f5c>] mark_page_dirty_in_slot+0xa4/0xb0 [kvm]
[ 1801.981083]  [<000003ff8060e9fe>] adapter_indicators_set+0xde/0x268 [kvm]
[ 1801.981104]  [<000003ff80613c24>] set_adapter_int+0x64/0xd8 [kvm]
[ 1801.981124]  [<000003ff805fb9aa>] kvm_set_irq+0xc2/0x130 [kvm]
[ 1801.981144]  [<000003ff805f8d86>] irqfd_inject+0x76/0xa0 [kvm]
[ 1801.981164]  [<0000000175e56906>] process_one_work+0x1fe/0x470
[ 1801.981173]  [<0000000175e570a4>] worker_thread+0x64/0x498
[ 1801.981176]  [<0000000175e5ef2c>] kthread+0x10c/0x110
[ 1801.981180]  [<0000000175de73c8>] __ret_from_fork+0x40/0x58
[ 1801.981185]  [<000000017698440a>] ret_from_fork+0xa/0x40

when writing to a guest from an irqfd worker as long as we do not have
the dirty ring.

Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reluctantly-acked-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20220113122924.740496-1-borntraeger@linux.ibm.com>
Fixes: 2efd61a608 ("KVM: Warn if mark_page_dirty() is called without an active vCPU")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19 12:13:02 -05:00
Linus Torvalds 79e06c4c49 RISCV:
- Use common KVM implementation of MMU memory caches
 
 - SBI v0.2 support for Guest
 
 - Initial KVM selftests support
 
 - Fix to avoid spurious virtual interrupts after clearing hideleg CSR
 
 - Update email address for Anup and Atish
 
 ARM:
 - Simplification of the 'vcpu first run' by integrating it into
   KVM's 'pid change' flow
 
 - Refactoring of the FP and SVE state tracking, also leading to
   a simpler state and less shared data between EL1 and EL2 in
   the nVHE case
 
 - Tidy up the header file usage for the nvhe hyp object
 
 - New HYP unsharing mechanism, finally allowing pages to be
   unmapped from the Stage-1 EL2 page-tables
 
 - Various pKVM cleanups around refcounting and sharing
 
 - A couple of vgic fixes for bugs that would trigger once
   the vcpu xarray rework is merged, but not sooner
 
 - Add minimal support for ARMv8.7's PMU extension
 
 - Rework kvm_pgtable initialisation ahead of the NV work
 
 - New selftest for IRQ injection
 
 - Teach selftests about the lack of default IPA space and
   page sizes
 
 - Expand sysreg selftest to deal with Pointer Authentication
 
 - The usual bunch of cleanups and doc update
 
 s390:
 - fix sigp sense/start/stop/inconsistency
 
 - cleanups
 
 x86:
 - Clean up some function prototypes more
 
 - improved gfn_to_pfn_cache with proper invalidation, used by Xen emulation
 
 - add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery
 
 - completely remove potential TOC/TOU races in nested SVM consistency checks
 
 - update some PMCs on emulated instructions
 
 - Intel AMX support (joint work between Thomas and Intel)
 
 - large MMU cleanups
 
 - module parameter to disable PMU virtualization
 
 - cleanup register cache
 
 - first part of halt handling cleanups
 
 - Hyper-V enlightened MSR bitmap support for nested hypervisors
 
 Generic:
 - clean up Makefiles
 
 - introduce CONFIG_HAVE_KVM_DIRTY_RING
 
 - optimize memslot lookup using a tree
 
 - optimize vCPU array usage by converting to xarray
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "RISCV:

   - Use common KVM implementation of MMU memory caches

   - SBI v0.2 support for Guest

   - Initial KVM selftests support

   - Fix to avoid spurious virtual interrupts after clearing hideleg CSR

   - Update email address for Anup and Atish

  ARM:

   - Simplification of the 'vcpu first run' by integrating it into KVM's
     'pid change' flow

   - Refactoring of the FP and SVE state tracking, also leading to a
     simpler state and less shared data between EL1 and EL2 in the nVHE
     case

   - Tidy up the header file usage for the nvhe hyp object

   - New HYP unsharing mechanism, finally allowing pages to be unmapped
     from the Stage-1 EL2 page-tables

   - Various pKVM cleanups around refcounting and sharing

   - A couple of vgic fixes for bugs that would trigger once the vcpu
     xarray rework is merged, but not sooner

   - Add minimal support for ARMv8.7's PMU extension

   - Rework kvm_pgtable initialisation ahead of the NV work

   - New selftest for IRQ injection

   - Teach selftests about the lack of default IPA space and page sizes

   - Expand sysreg selftest to deal with Pointer Authentication

   - The usual bunch of cleanups and doc update

  s390:

   - fix sigp sense/start/stop/inconsistency

   - cleanups

  x86:

   - Clean up some function prototypes more

   - improved gfn_to_pfn_cache with proper invalidation, used by Xen
     emulation

   - add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery

   - completely remove potential TOC/TOU races in nested SVM consistency
     checks

   - update some PMCs on emulated instructions

   - Intel AMX support (joint work between Thomas and Intel)

   - large MMU cleanups

   - module parameter to disable PMU virtualization

   - cleanup register cache

   - first part of halt handling cleanups

   - Hyper-V enlightened MSR bitmap support for nested hypervisors

  Generic:

   - clean up Makefiles

   - introduce CONFIG_HAVE_KVM_DIRTY_RING

   - optimize memslot lookup using a tree

   - optimize vCPU array usage by converting to xarray"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (268 commits)
  x86/fpu: Fix inline prefix warnings
  selftest: kvm: Add amx selftest
  selftest: kvm: Move struct kvm_x86_state to header
  selftest: kvm: Reorder vcpu_load_state steps for AMX
  kvm: x86: Disable interception for IA32_XFD on demand
  x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state()
  kvm: selftests: Add support for KVM_CAP_XSAVE2
  kvm: x86: Add support for getting/setting expanded xstate buffer
  x86/fpu: Add uabi_size to guest_fpu
  kvm: x86: Add CPUID support for Intel AMX
  kvm: x86: Add XCR0 support for Intel AMX
  kvm: x86: Disable RDMSR interception of IA32_XFD_ERR
  kvm: x86: Emulate IA32_XFD_ERR for guest
  kvm: x86: Intercept #NM for saving IA32_XFD_ERR
  x86/fpu: Prepare xfd_err in struct fpu_guest
  kvm: x86: Add emulation for IA32_XFD
  x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation
  kvm: x86: Enable dynamic xfeatures at KVM_SET_CPUID2
  x86/fpu: Provide fpu_enable_guest_xfd_features() for KVM
  x86/fpu: Add guest support to xfd_enable_feature()
  ...
2022-01-16 16:15:14 +02:00
Linus Torvalds 8e5b0adeea Peter Zijlstra says:
"Cleanup of the perf/kvm interaction."
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Merge tag 'perf_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf updates from Borislav Petkov:
 "Cleanup of the perf/kvm interaction."

* tag 'perf_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Drop guest callback (un)register stubs
  KVM: arm64: Drop perf.c and fold its tiny bits of code into arm.c
  KVM: arm64: Hide kvm_arm_pmu_available behind CONFIG_HW_PERF_EVENTS=y
  KVM: arm64: Convert to the generic perf callbacks
  KVM: x86: Move Intel Processor Trace interrupt handler to vmx.c
  KVM: Move x86's perf guest info callbacks to generic KVM
  KVM: x86: More precisely identify NMI from guest when handling PMI
  KVM: x86: Drop current_vcpu for kvm_running_vcpu + kvm_arch_vcpu variable
  perf/core: Use static_call to optimize perf_guest_info_callbacks
  perf: Force architectures to opt-in to guest callbacks
  perf: Add wrappers for invoking guest callbacks
  perf/core: Rework guest callbacks to prepare for static_call support
  perf: Drop dead and useless guest "support" from arm, csky, nds32 and riscv
  perf: Stop pretending that perf can handle multiple guest callbacks
  KVM: x86: Register Processor Trace interrupt hook iff PT enabled in guest
  KVM: x86: Register perf callbacks after calling vendor's hardware_setup()
  perf: Protect perf_guest_cbs with RCU
2022-01-12 16:26:58 -08:00
David Woodhouse 982ed0de47 KVM: Reinstate gfn_to_pfn_cache with invalidation support
This can be used in two modes. There is an atomic mode where the cached
mapping is accessed while holding the rwlock, and a mode where the
physical address is used by a vCPU in guest mode.

For the latter case, an invalidation will wake the vCPU with the new
KVM_REQ_GPC_INVALIDATE, and the architecture will need to refresh any
caches it still needs to access before entering guest mode again.

Only one vCPU can be targeted by the wake requests; it's simple enough
to make it wake all vCPUs or even a mask but I don't see a use case for
that additional complexity right now.

Invalidation happens from the invalidate_range_start MMU notifier, which
needs to be able to sleep in order to wake the vCPU and wait for it.

This means that revalidation potentially needs to "wait" for the MMU
operation to complete and the invalidate_range_end notifier to be
invoked. Like the vCPU when it takes a page fault in that period, we
just spin — fixing that in a future patch by implementing an actual
*wait* may be another part of shaving this particularly hirsute yak.

As noted in the comments in the function itself, the only case where
the invalidate_range_start notifier is expected to be called *without*
being able to sleep is when the OOM reaper is killing the process. In
that case, we expect the vCPU threads already to have exited, and thus
there will be nothing to wake, and no reason to wait. So we clear the
KVM_REQUEST_WAIT bit and send the request anyway, then complain loudly
if there actually *was* anything to wake up.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211210163625.2886-3-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-07 10:44:44 -05:00
David Woodhouse 2efd61a608 KVM: Warn if mark_page_dirty() is called without an active vCPU
The various kvm_write_guest() and mark_page_dirty() functions must only
ever be called in the context of an active vCPU, because if dirty ring
tracking is enabled it may simply oops when kvm_get_running_vcpu()
returns NULL for the vcpu and then kvm_dirty_ring_get() dereferences it.

This oops was reported by "butt3rflyh4ck" <butterflyhuangxx@gmail.com> in
https://lore.kernel.org/kvm/CAFcO6XOmoS7EacN_n6v4Txk7xL7iqRa2gABg3F7E3Naf5uG94g@mail.gmail.com/

That actual bug will be fixed under separate cover but this warning
should help to prevent new ones from being added.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211210163625.2886-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-07 10:44:44 -05:00
David Woodhouse 6f2cdbdba4 KVM: Add Makefile.kvm for common files, use it for x86
Splitting kvm_main.c out into smaller and better-organized files is
slightly non-trivial when it involves editing a bunch of per-arch
KVM makefiles. Provide virt/kvm/Makefile.kvm for them to include.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20211121125451.9489-3-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 12:56:02 -05:00