Commit Graph

2339 Commits

Author SHA1 Message Date
Linus Torvalds d3cf405133 VFIO updates for v6.1-rc1
- Prune private items from vfio_pci_core.h to a new internal header,
    fix missed function rename, and refactor vfio-pci interrupt defines.
    (Jason Gunthorpe)
 
  - Create consistent naming and handling of ioctls with a function per
    ioctl for vfio-pci and vfio group handling, use proper type args
    where available. (Jason Gunthorpe)
 
  - Implement a set of low power device feature ioctls allowing userspace
    to make use of power states such as D3cold where supported.
    (Abhishek Sahu)
 
  - Remove device counter on vfio groups, which had restricted the page
    pinning interface to singleton groups to account for limitations in
    the type1 IOMMU backend.  Document usage as limited to emulated IOMMU
    devices, ie. traditional mdev devices where this restriction is
    consistent.  (Jason Gunthorpe)
 
  - Correct function prefix in hisi_acc driver incurred during previous
    refactoring. (Shameer Kolothum)
 
  - Correct typo and remove redundant warning triggers in vfio-fsl driver.
    (Christophe JAILLET)
 
  - Introduce device level DMA dirty tracking uAPI and implementation in
    the mlx5 variant driver (Yishai Hadas & Joao Martins)
 
  - Move much of the vfio_device life cycle management into vfio core,
    simplifying and avoiding duplication across drivers.  This also
    facilitates adding a struct device to vfio_device which begins the
    introduction of device rather than group level user support and fills
    a gap allowing userspace identify devices as vfio capable without
    implicit knowledge of the driver. (Kevin Tian & Yi Liu)
 
  - Split vfio container handling to a separate file, creating a more
    well defined API between the core and container code, masking IOMMU
    backend implementation from the core, allowing for an easier future
    transition to an iommufd based implementation of the same.
    (Jason Gunthorpe)
 
  - Attempt to resolve race accessing the iommu_group for a device
    between vfio releasing DMA ownership and removal of the device from
    the IOMMU driver.  Follow-up with support to allow vfio_group to
    exist with NULL iommu_group pointer to support existing userspace
    use cases of holding the group file open.  (Jason Gunthorpe)
 
  - Fix error code and hi/lo register manipulation issues in the hisi_acc
    variant driver, along with various code cleanups. (Longfang Liu)
 
  - Fix a prior regression in GVT-g group teardown, resulting in
    unreleased resources. (Jason Gunthorpe)
 
  - A significant cleanup and simplification of the mdev interface,
    consolidating much of the open coded per driver sysfs interface
    support into the mdev core. (Christoph Hellwig)
 
  - Simplification of tracking and locking around vfio_groups that
    fall out from previous refactoring. (Jason Gunthorpe)
 
  - Replace trivial open coded f_ops tests with new helper.
    (Alex Williamson)
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Merge tag 'vfio-v6.1-rc1' of https://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - Prune private items from vfio_pci_core.h to a new internal header,
   fix missed function rename, and refactor vfio-pci interrupt defines
   (Jason Gunthorpe)

 - Create consistent naming and handling of ioctls with a function per
   ioctl for vfio-pci and vfio group handling, use proper type args
   where available (Jason Gunthorpe)

 - Implement a set of low power device feature ioctls allowing userspace
   to make use of power states such as D3cold where supported (Abhishek
   Sahu)

 - Remove device counter on vfio groups, which had restricted the page
   pinning interface to singleton groups to account for limitations in
   the type1 IOMMU backend. Document usage as limited to emulated IOMMU
   devices, ie. traditional mdev devices where this restriction is
   consistent (Jason Gunthorpe)

 - Correct function prefix in hisi_acc driver incurred during previous
   refactoring (Shameer Kolothum)

 - Correct typo and remove redundant warning triggers in vfio-fsl driver
   (Christophe JAILLET)

 - Introduce device level DMA dirty tracking uAPI and implementation in
   the mlx5 variant driver (Yishai Hadas & Joao Martins)

 - Move much of the vfio_device life cycle management into vfio core,
   simplifying and avoiding duplication across drivers. This also
   facilitates adding a struct device to vfio_device which begins the
   introduction of device rather than group level user support and fills
   a gap allowing userspace identify devices as vfio capable without
   implicit knowledge of the driver (Kevin Tian & Yi Liu)

 - Split vfio container handling to a separate file, creating a more
   well defined API between the core and container code, masking IOMMU
   backend implementation from the core, allowing for an easier future
   transition to an iommufd based implementation of the same (Jason
   Gunthorpe)

 - Attempt to resolve race accessing the iommu_group for a device
   between vfio releasing DMA ownership and removal of the device from
   the IOMMU driver. Follow-up with support to allow vfio_group to exist
   with NULL iommu_group pointer to support existing userspace use cases
   of holding the group file open (Jason Gunthorpe)

 - Fix error code and hi/lo register manipulation issues in the hisi_acc
   variant driver, along with various code cleanups (Longfang Liu)

 - Fix a prior regression in GVT-g group teardown, resulting in
   unreleased resources (Jason Gunthorpe)

 - A significant cleanup and simplification of the mdev interface,
   consolidating much of the open coded per driver sysfs interface
   support into the mdev core (Christoph Hellwig)

 - Simplification of tracking and locking around vfio_groups that fall
   out from previous refactoring (Jason Gunthorpe)

 - Replace trivial open coded f_ops tests with new helper (Alex
   Williamson)

* tag 'vfio-v6.1-rc1' of https://github.com/awilliam/linux-vfio: (77 commits)
  vfio: More vfio_file_is_group() use cases
  vfio: Make the group FD disassociate from the iommu_group
  vfio: Hold a reference to the iommu_group in kvm for SPAPR
  vfio: Add vfio_file_is_group()
  vfio: Change vfio_group->group_rwsem to a mutex
  vfio: Remove the vfio_group->users and users_comp
  vfio/mdev: add mdev available instance checking to the core
  vfio/mdev: consolidate all the description sysfs into the core code
  vfio/mdev: consolidate all the available_instance sysfs into the core code
  vfio/mdev: consolidate all the name sysfs into the core code
  vfio/mdev: consolidate all the device_api sysfs into the core code
  vfio/mdev: remove mtype_get_parent_dev
  vfio/mdev: remove mdev_parent_dev
  vfio/mdev: unexport mdev_bus_type
  vfio/mdev: remove mdev_from_dev
  vfio/mdev: simplify mdev_type handling
  vfio/mdev: embedd struct mdev_parent in the parent data structure
  vfio/mdev: make mdev.h standalone includable
  drm/i915/gvt: simplify vgpu configuration management
  drm/i915/gvt: fix a memory leak in intel_gvt_init_vgpu_types
  ...
2022-10-12 14:46:48 -07:00
Jason Gunthorpe 819da99a73 vfio: Hold a reference to the iommu_group in kvm for SPAPR
SPAPR exists completely outside the normal iommu driver framework, the
groups it creates are fake and are only created to enable VFIO's uAPI.

Thus, it does not need to follow the iommu core rule that the iommu_group
will only be touched while a driver is attached.

Carry a group reference into KVM and have KVM directly manage the lifetime
of this object independently of VFIO. This means KVM no longer relies on
the vfio group file being valid to maintain the group reference.

Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/2-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-10-07 08:10:52 -06:00
Jason Gunthorpe 4b22ef042d vfio: Add vfio_file_is_group()
This replaces uses of vfio_file_iommu_group() which were only detecting if
the file is a VFIO file with no interest in the actual group.

The only remaning user of vfio_file_iommu_group() is in KVM for the SPAPR
stuff. It passes the iommu_group into the arch code through kvm for some
reason.

Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/1-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-10-07 08:10:52 -06:00
Paolo Bonzini fe4d9e4abf KVM/arm64 updates for v6.1
- Fixes for single-stepping in the presence of an async
   exception as well as the preservation of PSTATE.SS
 
 - Better handling of AArch32 ID registers on AArch64-only
   systems
 
 - Fixes for the dirty-ring API, allowing it to work on
   architectures with relaxed memory ordering
 
 - Advertise the new kvmarm mailing list
 
 - Various minor cleanups and spelling fixes
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Merge tag 'kvmarm-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for v6.1

- Fixes for single-stepping in the presence of an async
  exception as well as the preservation of PSTATE.SS

- Better handling of AArch32 ID registers on AArch64-only
  systems

- Fixes for the dirty-ring API, allowing it to work on
  architectures with relaxed memory ordering

- Advertise the new kvmarm mailing list

- Various minor cleanups and spelling fixes
2022-10-03 15:33:32 -04:00
Marc Zyngier 17601bfed9 KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config option
In order to differenciate between architectures that require no extra
synchronisation when accessing the dirty ring and those who do,
add a new capability (KVM_CAP_DIRTY_LOG_RING_ACQ_REL) that identify
the latter sort. TSO architectures can obviously advertise both, while
relaxed architectures must only advertise the ACQ_REL version.

This requires some configuration symbol rejigging, with HAVE_KVM_DIRTY_RING
being only indirectly selected by two top-level config symbols:
- HAVE_KVM_DIRTY_RING_TSO for strongly ordered architectures (x86)
- HAVE_KVM_DIRTY_RING_ACQ_REL for weakly ordered architectures (arm64)

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20220926145120.27974-3-maz@kernel.org
2022-09-29 10:23:08 +01:00
Marc Zyngier 8929bc9659 KVM: Use acquire/release semantics when accessing dirty ring GFN state
The current implementation of the dirty ring has an implicit requirement
that stores to the dirty ring from userspace must be:

- be ordered with one another

- visible from another CPU executing a ring reset

While these implicit requirements work well for x86 (and any other
TSO-like architecture), they do not work for more relaxed architectures
such as arm64 where stores to different addresses can be freely
reordered, and loads from these addresses not observing writes from
another CPU unless the required barriers (or acquire/release semantics)
are used.

In order to start fixing this, upgrade the ring reset accesses:

- the kvm_dirty_gfn_harvested() helper now uses acquire semantics
  so it is ordered after all previous writes, including that from
  userspace

- the kvm_dirty_gfn_set_invalid() helper now uses release semantics
  so that the next_slot and next_offset reads don't drift past
  the entry invalidation

This is only a partial fix as the userspace side also need upgrading.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20220926145120.27974-2-maz@kernel.org
2022-09-29 10:23:08 +01:00
Paolo Bonzini c59fb12758 KVM: remove KVM_REQ_UNHALT
KVM_REQ_UNHALT is now unnecessary because it is replaced by the return
value of kvm_vcpu_block/kvm_vcpu_halt.  Remove it.

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20220921003201.1441511-13-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26 12:37:21 -04:00
Miaohe Lin 5a2a961be2 KVM: fix memoryleak in kvm_init()
When alloc_cpumask_var_node() fails for a certain cpu, there might be some
allocated cpumasks for percpu cpu_kick_mask. We should free these cpumasks
or memoryleak will occur.

Fixes: baff59ccdc ("KVM: Pre-allocate cpumasks for kvm_make_all_cpus_request_except()")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Link: https://lore.kernel.org/r/20220823063414.59778-1-linmiaohe@huawei.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26 12:02:27 -04:00
Li kunyu eceb6e1d53 KVM: Drop unnecessary initialization of "ops" in kvm_ioctl_create_device()
The variable is initialized but it is only used after its assignment.

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Li kunyu <kunyu@nfschina.com>
Message-Id: <20220819021535.483702-1-kunyu@nfschina.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19 04:05:43 -04:00
Li kunyu 2824913976 KVM: Drop unnecessary initialization of "npages" in hva_to_pfn_slow()
The variable is initialized but it is only used after its assignment.

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Li kunyu <kunyu@nfschina.com>
Message-Id: <20220819022804.483914-1-kunyu@nfschina.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19 04:05:43 -04:00
Chao Peng 20ec3ebd70 KVM: Rename mmu_notifier_* to mmu_invalidate_*
The motivation of this renaming is to make these variables and related
helper functions less mmu_notifier bound and can also be used for non
mmu_notifier based page invalidation. mmu_invalidate_* was chosen to
better describe the purpose of 'invalidating' a page that those
variables are used for.

  - mmu_notifier_seq/range_start/range_end are renamed to
    mmu_invalidate_seq/range_start/range_end.

  - mmu_notifier_retry{_hva} helper functions are renamed to
    mmu_invalidate_retry{_hva}.

  - mmu_notifier_count is renamed to mmu_invalidate_in_progress to
    avoid confusion with mn_active_invalidate_count.

  - While here, also update kvm_inc/dec_notifier_count() to
    kvm_mmu_invalidate_begin/end() to match the change for
    mmu_notifier_count.

No functional change intended.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Message-Id: <20220816125322.1110439-3-chao.p.peng@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19 04:05:41 -04:00
Sean Christopherson c2b8239701 KVM: Move coalesced MMIO initialization (back) into kvm_create_vm()
Invoke kvm_coalesced_mmio_init() from kvm_create_vm() now that allocating
and initializing coalesced MMIO objects is separate from registering any
associated devices.  Moving coalesced MMIO cleans up the last oddity
where KVM does VM creation/initialization after kvm_create_vm(), and more
importantly after kvm_arch_post_init_vm() is called and the VM is added
to the global vm_list, i.e. after the VM is fully created as far as KVM
is concerned.

Originally, kvm_coalesced_mmio_init() was called by kvm_create_vm(), but
the original implementation was completely devoid of error handling.
Commit 6ce5a090a9 ("KVM: coalesced_mmio: fix kvm_coalesced_mmio_init()'s
error handling" fixed the various bugs, and in doing so rightly moved the
call to after kvm_create_vm() because kvm_coalesced_mmio_init() also
registered the coalesced MMIO device.  Commit 2b3c246a68 ("KVM: Make
coalesced mmio use a device per zone") cleaned up that mess by having
each zone register a separate device, i.e. moved device registration to
its logical home in kvm_vm_ioctl_register_coalesced_mmio().  As a result,
kvm_coalesced_mmio_init() is now a "pure" initialization helper and can
be safely called from kvm_create_vm().

Opportunstically drop the #ifdef, KVM provides stubs for
kvm_coalesced_mmio_{init,free}() when CONFIG_KVM_MMIO=n (s390).

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220816053937.2477106-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19 04:02:31 -04:00
Sean Christopherson 405294f29f KVM: Unconditionally get a ref to /dev/kvm module when creating a VM
Unconditionally get a reference to the /dev/kvm module when creating a VM
instead of using try_get_module(), which will fail if the module is in
the process of being forcefully unloaded.  The error handling when
try_get_module() fails doesn't properly unwind all that has been done,
e.g. doesn't call kvm_arch_pre_destroy_vm() and doesn't remove the VM
from the global list.  Not removing VMs from the global list tends to be
fatal, e.g. leads to use-after-free explosions.

The obvious alternative would be to add proper unwinding, but the
justification for using try_get_module(), "rmmod --wait", is completely
bogus as support for "rmmod --wait", i.e. delete_module() without
O_NONBLOCK, was removed by commit 3f2b9c9cdf ("module: remove rmmod
--wait option.") nearly a decade ago.

It's still possible for try_get_module() to fail due to the module dying
(more like being killed), as the module will be tagged MODULE_STATE_GOING
by "rmmod --force", i.e. delete_module(..., O_TRUNC), but playing nice
with forced unloading is an exercise in futility and gives a falsea sense
of security.  Using try_get_module() only prevents acquiring _new_
references, it doesn't magically put the references held by other VMs,
and forced unloading doesn't wait, i.e. "rmmod --force" on KVM is all but
guaranteed to cause spectacular fireworks; the window where KVM will fail
try_get_module() is tiny compared to the window where KVM is building and
running the VM with an elevated module refcount.

Addressing KVM's inability to play nice with "rmmod --force" is firmly
out-of-scope.  Forcefully unloading any module taints kernel (for obvious
reasons)  _and_ requires the kernel to be built with
CONFIG_MODULE_FORCE_UNLOAD=y, which is off by default and comes with the
amusing disclaimer that it's "mainly for kernel developers and desperate
users".  In other words, KVM is free to scoff at bug reports due to using
"rmmod --force" while VMs may be running.

Fixes: 5f6de5cbeb ("KVM: Prevent module exit until all VMs are freed")
Cc: stable@vger.kernel.org
Cc: David Matlack <dmatlack@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220816053937.2477106-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19 04:02:31 -04:00
Sean Christopherson 4ba4f41942 KVM: Properly unwind VM creation if creating debugfs fails
Properly unwind VM creation if kvm_create_vm_debugfs() fails.  A recent
change to invoke kvm_create_vm_debug() in kvm_create_vm() was led astray
by buggy try_get_module() handling adding by commit 5f6de5cbeb ("KVM:
Prevent module exit until all VMs are freed").  The debugfs error path
effectively inherits the bad error path of try_module_get(), e.g. KVM
leaves the to-be-free VM on vm_list even though KVM appears to do the
right thing by calling module_put() and falling through.

Opportunistically hoist kvm_create_vm_debugfs() above the call to
kvm_arch_post_init_vm() so that the "post-init" arch hook is actually
invoked after the VM is initialized (ignoring kvm_coalesced_mmio_init()
for the moment).  x86 is the only non-nop implementation of the post-init
hook, and it doesn't allocate/initialize any objects that are reachable
via debugfs code (spawns a kthread worker for the NX huge page mitigation).

Leave the buggy try_get_module() alone for now, it will be fixed in a
separate commit.

Fixes: b74ed7a68e ("KVM: Actually create debugfs in kvm_create_vm()")
Reported-by: syzbot+744e173caec2e1627ee0@syzkaller.appspotmail.com
Cc: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Message-Id: <20220816053937.2477106-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19 04:02:30 -04:00
Oliver Upton b74ed7a68e KVM: Actually create debugfs in kvm_create_vm()
Doing debugfs creation after vm creation leaves things in a
quasi-initialized state for a while. This is further complicated by the
fact that we tear down debugfs from kvm_destroy_vm(). Align debugfs and
stats init/destroy with the vm init/destroy pattern to avoid any
headaches.

Note the fix for a benign mistake in error handling for calls to
kvm_arch_create_vm_debugfs() rolled in. Since all implementations of
the function return 0 unconditionally it isn't actually a bug at
the moment.

Lastly, tear down debugfs/stats data in the kvm_create_vm_debugfs()
error path. Previously it was safe to assume that kvm_destroy_vm() would
take out the garbage, that is no longer the case.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-6-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:28 -04:00
Oliver Upton 59f82aad59 KVM: Pass the name of the VM fd to kvm_create_vm_debugfs()
At the time the VM fd is used in kvm_create_vm_debugfs(), the fd has
been allocated but not yet installed. It is only really useful as an
identifier in strings for the VM (such as debugfs).

Treat it exactly as such by passing the string name of the fd to
kvm_create_vm_debugfs(), futureproofing against possible misuse of the
VM fd.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-5-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:28 -04:00
Oliver Upton 20020f4cf2 KVM: Get an fd before creating the VM
Allocate a VM's fd at the very beginning of kvm_dev_ioctl_create_vm() so
that KVM can use the fd value to generate strigns, e.g. for debugfs,
when creating and initializing the VM.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-4-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:27 -04:00
Oliver Upton 58fc116645 KVM: Shove vcpu stats_id init into kvm_vcpu_init()
Initialize stats_id alongside other kvm_vcpu fields to make it more
difficult to unintentionally access stats_id before it's set.

No functional change intended.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-3-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:27 -04:00
Oliver Upton f2759c08d8 KVM: Shove vm stats_id init into kvm_create_vm()
Initialize stats_id alongside other struct kvm fields to make it more
difficult to unintentionally access stats_id before it's set.  While at
it, move the format string to the first line of the call and fix the
indentation of the second line.

No functional change intended.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-2-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10 15:08:27 -04:00
Paolo Bonzini 63f4b21041 Merge remote-tracking branch 'kvm/next' into kvm-next-5.20
KVM/s390, KVM/x86 and common infrastructure changes for 5.20

x86:

* Permit guests to ignore single-bit ECC errors

* Fix races in gfn->pfn cache refresh; do not pin pages tracked by the cache

* Intel IPI virtualization

* Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS

* PEBS virtualization

* Simplify PMU emulation by just using PERF_TYPE_RAW events

* More accurate event reinjection on SVM (avoid retrying instructions)

* Allow getting/setting the state of the speaker port data bit

* Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls are inconsistent

* "Notify" VM exit (detect microarchitectural hangs) for Intel

* Cleanups for MCE MSR emulation

s390:

* add an interface to provide a hypervisor dump for secure guests

* improve selftests to use TAP interface

* enable interpretive execution of zPCI instructions (for PCI passthrough)

* First part of deferred teardown

* CPU Topology

* PV attestation

* Minor fixes

Generic:

* new selftests API using struct kvm_vcpu instead of a (vm, id) tuple

x86:

* Use try_cmpxchg64 instead of cmpxchg64

* Bugfixes

* Ignore benign host accesses to PMU MSRs when PMU is disabled

* Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior

* x86/MMU: Allow NX huge pages to be disabled on a per-vm basis

* Port eager page splitting to shadow MMU as well

* Enable CMCI capability by default and handle injected UCNA errors

* Expose pid of vcpu threads in debugfs

* x2AVIC support for AMD

* cleanup PIO emulation

* Fixes for LLDT/LTR emulation

* Don't require refcounted "struct page" to create huge SPTEs

x86 cleanups:

* Use separate namespaces for guest PTEs and shadow PTEs bitmasks

* PIO emulation

* Reorganize rmap API, mostly around rmap destruction

* Do not workaround very old KVM bugs for L0 that runs with nesting enabled

* new selftests API for CPUID
2022-08-01 03:21:00 -04:00
Anup Patel 4ab0e470c0 KVM: Add gfp_custom flag in struct kvm_mmu_memory_cache
The kvm_mmu_topup_memory_cache() always uses GFP_KERNEL_ACCOUNT for
memory allocation which prevents it's use in atomic context. To address
this limitation of kvm_mmu_topup_memory_cache(), we add gfp_custom flag
in struct kvm_mmu_memory_cache. When the gfp_custom flag is set to some
GFP_xyz flags, the kvm_mmu_topup_memory_cache() will use that instead of
GFP_KERNEL_ACCOUNT.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
2022-07-29 17:15:00 +05:30
Vineeth Pillai e36de87d34 KVM: debugfs: expose pid of vcpu threads
Add a new debugfs file to expose the pid of each vcpu threads. This
is very helpful for userland tools to get the vcpu pids without
worrying about thread naming conventions of the VMM.

Signed-off-by: Vineeth Pillai (Google) <vineeth@bitbyteword.org>
Message-Id: <20220523190327.2658-1-vineeth@bitbyteword.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24 12:44:33 -04:00
David Matlack 837f66c712 KVM: Allow for different capacities in kvm_mmu_memory_cache structs
Allow the capacity of the kvm_mmu_memory_cache struct to be chosen at
declaration time rather than being fixed for all declarations. This will
be used in a follow-up commit to declare an cache in x86 with a capacity
of 512+ objects without having to increase the capacity of all caches in
KVM.

This change requires each cache now specify its capacity at runtime,
since the cache struct itself no longer has a fixed capacity known at
compile time. To protect against someone accidentally defining a
kvm_mmu_memory_cache struct directly (without the extra storage), this
commit includes a WARN_ON() in kvm_mmu_topup_memory_cache().

In order to support different capacities, this commit changes the
objects pointer array to be dynamically allocated the first time the
cache is topped-up.

While here, opportunistically clean up the stack-allocated
kvm_mmu_memory_cache structs in riscv and arm64 to use designated
initializers.

No functional change intended.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220516232138.1783324-22-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24 04:52:00 -04:00
Sean Christopherson 943dfea8f1 KVM: Do not zero initialize 'pfn' in hva_to_pfn()
Drop the unnecessary initialization of the local 'pfn' variable in
hva_to_pfn().  First and foremost, '0' is not an invalid pfn, it's a
perfectly valid pfn on most architectures.  I.e. if hva_to_pfn() were to
return an "uninitializd" pfn, it would actually be interpeted as a legal
pfn by most callers.

Second, hva_to_pfn() can't return an uninitialized pfn as hva_to_pfn()
explicitly sets pfn to an error value (or returns an error value directly)
if a helper returns failure, and all helpers set the pfn on success.

The zeroing of 'pfn' was introduced by commit 2fc843117d ("KVM:
reorganize hva_to_pfn"), probably to avoid "uninitialized variable"
warnings on statements that return pfn.  However, no compiler seems
to produce them, making the initialization unnecessary.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:36 -04:00
Sean Christopherson b14b2690c5 KVM: Rename/refactor kvm_is_reserved_pfn() to kvm_pfn_to_refcounted_page()
Rename and refactor kvm_is_reserved_pfn() to kvm_pfn_to_refcounted_page()
to better reflect what KVM is actually checking, and to eliminate extra
pfn_to_page() lookups.  The kvm_release_pfn_*() an kvm_try_get_pfn()
helpers in particular benefit from "refouncted" nomenclature, as it's not
all that obvious why KVM needs to get/put refcounts for some PG_reserved
pages (ZERO_PAGE and ZONE_DEVICE).

Add a comment to call out that the list of exceptions to PG_reserved is
all but guaranteed to be incomplete.  The list has mostly been compiled
by people throwing noodles at KVM and finding out they stick a little too
well, e.g. the ZERO_PAGE's refcount overflowed and ZONE_DEVICE pages
didn't get freed.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:35 -04:00
Sean Christopherson 284dc49307 KVM: Take a 'struct page', not a pfn in kvm_is_zone_device_page()
Operate on a 'struct page' instead of a pfn when checking if a page is a
ZONE_DEVICE page, and rename the helper accordingly.  Generally speaking,
KVM doesn't actually care about ZONE_DEVICE memory, i.e. shouldn't do
anything special for ZONE_DEVICE memory.  Rather, KVM wants to treat
ZONE_DEVICE memory like regular memory, and the need to identify
ZONE_DEVICE memory only arises as an exception to PG_reserved pages. In
other words, KVM should only ever check for ZONE_DEVICE memory after KVM
has already verified that there is a struct page associated with the pfn.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:34 -04:00
Sean Christopherson b1624f99aa KVM: Remove kvm_vcpu_gfn_to_page() and kvm_vcpu_gpa_to_page()
Drop helpers to convert a gfn/gpa to a 'struct page' in the context of a
vCPU.  KVM doesn't require that guests be backed by 'struct page' memory,
thus any use of helpers that assume 'struct page' is bound to be flawed,
as was the case for the recently removed last user in x86's nested VMX.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:34 -04:00
Sean Christopherson 6573a6910c KVM: Don't WARN if kvm_pfn_to_page() encounters a "reserved" pfn
Drop a WARN_ON() if kvm_pfn_to_page() encounters a "reserved" pfn, which
in this context means a struct page that has PG_reserved but is not a/the
ZERO_PAGE and is not a ZONE_DEVICE page.  The usage, via gfn_to_page(),
in x86 is safe as gfn_to_page() is used only to retrieve a page from
KVM-controlled memslot, but the usage in PPC and s390 operates on
arbitrary gfns and thus memslots that can be backed by incompatible
memory.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:33 -04:00
Sean Christopherson 8e1c69149f KVM: Avoid pfn_to_page() and vice versa when releasing pages
Invert the order of KVM's page/pfn release helpers so that the "inner"
helper operates on a page instead of a pfn.  As pointed out by Linus[*],
converting between struct page and a pfn isn't necessarily cheap, and
that's not even counting the overhead of is_error_noslot_pfn() and
kvm_is_reserved_pfn().  Even if the checks were dirt cheap, there's no
reason to convert from a page to a pfn and back to a page, just to mark
the page dirty/accessed or to put a reference to the page.

Opportunistically drop a stale declaration of kvm_set_page_accessed()
from kvm_host.h (there was no implementation).

No functional change intended.

[*] https://lore.kernel.org/all/CAHk-=wifQimj2d6npq-wCi5onYPjzQg4vyO4tFcPJJZr268cRw@mail.gmail.com

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:32 -04:00
Sean Christopherson a1040b0d42 KVM: Don't set Accessed/Dirty bits for ZERO_PAGE
Don't set Accessed/Dirty bits for a struct page with PG_reserved set,
i.e. don't set A/D bits for the ZERO_PAGE.  The ZERO_PAGE (or pages
depending on the architecture) should obviously never be written, and
similarly there's no point in marking it accessed as the page will never
be swapped out or reclaimed.  The comment in page-flags.h is quite clear
that PG_reserved pages should be managed only by their owner, and
strictly following that mandate also simplifies KVM's logic.

Fixes: 7df003c852 ("KVM: fix overflow of zero page refcount with ksm running")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:31 -04:00
Sean Christopherson 28b85ae06f KVM: Drop bogus "pfn != 0" guard from kvm_release_pfn()
Remove a check from kvm_release_pfn() to bail if the provided @pfn is
zero.  Zero is a perfectly valid pfn on most architectures, and should
not be used to indicate an error or an invalid pfn.  The bogus check was
added by commit 917248144d ("x86/kvm: Cache gfn to pfn translation"),
which also did the bad thing of zeroing the pfn and gfn to mark a cache
invalid.  Thankfully, that bad behavior was axed by commit 357a18ad23
("KVM: Kill kvm_map_gfn() / kvm_unmap_gfn() and gfn_to_pfn_cache").

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20 06:21:31 -04:00
Lai Jiangshan f24b44e48d KVM: Rename ack_flush() to ack_kick()
Make it use the same verb as in kvm_kick_many_cpus().

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Message-Id: <20220605063417.308311-5-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-15 08:07:53 -04:00
Paolo Bonzini e15f5e6fa6 Merge branch 'kvm-5.20-early'
s390:

* add an interface to provide a hypervisor dump for secure guests

* improve selftests to show tests

x86:

* Intel IPI virtualization

* Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS

* PEBS virtualization

* Simplify PMU emulation by just using PERF_TYPE_RAW events

* More accurate event reinjection on SVM (avoid retrying instructions)

* Allow getting/setting the state of the speaker port data bit

* Rewrite gfn-pfn cache refresh

* Refuse starting the module if VM-Entry/VM-Exit controls are inconsistent

* "Notify" VM exit
2022-06-09 11:38:12 -04:00
Maxim Levitsky 18869f26df KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking
On SVM, if preemption happens right after the call to finish_rcuwait
but before call to kvm_arch_vcpu_unblocking on SVM/AVIC, it itself
will re-enable AVIC, and then we will try to re-enable it again
in kvm_arch_vcpu_unblocking which will lead to a warning
in __avic_vcpu_load.

The same problem can happen if the vCPU is preempted right after the call
to kvm_arch_vcpu_blocking but before the call to prepare_to_rcuwait
and in this case, we will end up with AVIC enabled during sleep -
Ooops.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-7-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-09 10:52:20 -04:00
Paolo Bonzini 66da65005a KVM/riscv fixes for 5.19, take #1
- Typo fix in arch/riscv/kvm/vmid.c
 
 - Remove broken reference pattern from MAINTAINERS entry
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Merge tag 'kvm-riscv-fixes-5.19-1' of https://github.com/kvm-riscv/linux into HEAD

KVM/riscv fixes for 5.19, take #1

- Typo fix in arch/riscv/kvm/vmid.c

- Remove broken reference pattern from MAINTAINERS entry
2022-06-09 09:45:00 -04:00
Zeng Guang 1d5e740d51 KVM: Move kvm_arch_vcpu_precreate() under kvm->lock
kvm_arch_vcpu_precreate() targets to handle arch specific VM resource
to be prepared prior to the actual creation of vCPU. For example, x86
platform may need do per-VM allocation based on max_vcpu_ids at the
first vCPU creation. It probably leads to concurrency control on this
allocation as multiple vCPU creation could happen simultaneously. From
the architectual point of view, it's necessary to execute
kvm_arch_vcpu_precreate() under protect of kvm->lock.

Currently only arm64, x86 and s390 have non-nop implementations at the
stage of vCPU pre-creation. Remove the lock acquiring in s390's design
and make sure all architecture can run kvm_arch_vcpu_precreate() safely
under kvm->lock without recrusive lock issue.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Zeng Guang <guang.zeng@intel.com>
Message-Id: <20220419154409.11842-1-guang.zeng@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-08 04:47:28 -04:00
Paolo Bonzini b31455e96f Merge branch 'kvm-5.20-early-patches' into HEAD 2022-06-07 12:06:39 -04:00
Paolo Bonzini a280e35846 Merge branch 'kvm-5.19-early-fixes' into HEAD 2022-06-07 12:06:02 -04:00
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
Sean Christopherson 85165781c5 KVM: Do not pin pages tracked by gfn=>pfn caches
Put the reference to any struct page mapped/tracked by a gfn=>pfn cache
upon inserting the pfn into its associated cache, as opposed to putting
the reference only when the cache is done using the pfn.  In other words,
don't pin pages while they're in the cache.  One of the major roles of
the gfn=>pfn cache is to play nicely with invalidation events, i.e. it
exists in large part so that KVM doesn't rely on pinning pages.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429210025.3293691-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-25 05:23:44 -04:00
Sean Christopherson 58cd407ca4 KVM: Fix multiple races in gfn=>pfn cache refresh
Rework the gfn=>pfn cache (gpc) refresh logic to address multiple races
between the cache itself, and between the cache and mmu_notifier events.

The existing refresh code attempts to guard against races with the
mmu_notifier by speculatively marking the cache valid, and then marking
it invalid if a mmu_notifier invalidation occurs.  That handles the case
where an invalidation occurs between dropping and re-acquiring gpc->lock,
but it doesn't handle the scenario where the cache is refreshed after the
cache was invalidated by the notifier, but before the notifier elevates
mmu_notifier_count.  The gpc refresh can't use the "retry" helper as its
invalidation occurs _before_ mmu_notifier_count is elevated and before
mmu_notifier_range_start is set/updated.

  CPU0                                    CPU1
  ----                                    ----

  gfn_to_pfn_cache_invalidate_start()
  |
  -> gpc->valid = false;
                                          kvm_gfn_to_pfn_cache_refresh()
                                          |
                                          |-> gpc->valid = true;

                                          hva_to_pfn_retry()
                                          |
                                          -> acquire kvm->mmu_lock
                                             kvm->mmu_notifier_count == 0
                                             mmu_seq == kvm->mmu_notifier_seq
                                             drop kvm->mmu_lock
                                             return pfn 'X'
  acquire kvm->mmu_lock
  kvm_inc_notifier_count()
  drop kvm->mmu_lock()
  kernel frees pfn 'X'
                                          kvm_gfn_to_pfn_cache_check()
                                          |
                                          |-> gpc->valid == true

                                          caller accesses freed pfn 'X'

Key off of mn_active_invalidate_count to detect that a pfncache refresh
needs to wait for an in-progress mmu_notifier invalidation.  While
mn_active_invalidate_count is not guaranteed to be stable, it is
guaranteed to be elevated prior to an invalidation acquiring gpc->lock,
so either the refresh will see an active invalidation and wait, or the
invalidation will run after the refresh completes.

Speculatively marking the cache valid is itself flawed, as a concurrent
kvm_gfn_to_pfn_cache_check() would see a valid cache with stale pfn/khva
values.  The KVM Xen use case explicitly allows/wants multiple users;
even though the caches are allocated per vCPU, __kvm_xen_has_interrupt()
can read a different vCPU (or vCPUs).  Address this race by invalidating
the cache prior to dropping gpc->lock (this is made possible by fixing
the above mmu_notifier race).

Complicating all of this is the fact that both the hva=>pfn resolution
and mapping of the kernel address can sleep, i.e. must be done outside
of gpc->lock.

Fix the above races in one fell swoop, trying to fix each individual race
is largely pointless and essentially impossible to test, e.g. closing one
hole just shifts the focus to the other hole.

Fixes: 982ed0de47 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support")
Cc: stable@vger.kernel.org
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429210025.3293691-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-25 05:23:44 -04:00
Sean Christopherson 93984f19e7 KVM: Fully serialize gfn=>pfn cache refresh via mutex
Protect gfn=>pfn cache refresh with a mutex to fully serialize refreshes.
The refresh logic doesn't protect against

- concurrent unmaps, or refreshes with different GPAs (which may or may not
  happen in practice, for example if a cache is only used under vcpu->mutex;
  but it's allowed in the code)

- a false negative on the memslot generation.  If the first refresh sees
  a stale memslot generation, it will refresh the hva and generation before
  moving on to the hva=>pfn translation.  If it then drops gpc->lock, a
  different user of the cache can come along, acquire gpc->lock, see that
  the memslot generation is fresh, and skip the hva=>pfn update due to the
  userspace address also matching (because it too was updated).

The refresh path can already sleep during hva=>pfn resolution, so wrap
the refresh with a mutex to ensure that any given refresh runs to
completion before other callers can start their refresh.

Cc: stable@vger.kernel.org
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429210025.3293691-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-25 05:23:43 -04:00
Sean Christopherson 3ba2c95ea1 KVM: Do not incorporate page offset into gfn=>pfn cache user address
Don't adjust the userspace address in the gfn=>pfn cache by the page
offset from the gpa.  KVM should never use the user address directly, and
all KVM operations that translate a user address to something else
require the user address to be page aligned.  Ignoring the offset will
allow the cache to reuse a gfn=>hva translation in the unlikely event
that the page offset of the gpa changes, but the gfn does not.  And more
importantly, not having to (un)adjust the user address will simplify a
future bug fix.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429210025.3293691-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-25 05:23:42 -04:00
Sean Christopherson 3dddf65b4f KVM: Put the extra pfn reference when reusing a pfn in the gpc cache
Put the struct page reference to pfn acquired by hva_to_pfn() when the
old and new pfns for a gfn=>pfn cache match.  The cache already has a
reference via the old/current pfn, and will only put one reference when
the cache is done with the pfn.

Fixes: 982ed0de47 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429210025.3293691-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-25 05:23:41 -04:00
Sean Christopherson 345b0fd6fe KVM: Drop unused @gpa param from gfn=>pfn cache's __release_gpc() helper
Drop the @pga param from __release_gpc() and rename the helper to make it
more obvious that the cache itself is not being released.  The helper
will be reused by a future commit to release a pfn+khva combination that
is _never_ associated with the cache, at which point the current name
would go from slightly misleading to blatantly wrong.

No functional change intended.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220429210025.3293691-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-25 05:23:41 -04:00
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