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  1. 30 9月, 2020 4 次提交
  3. 21 8月, 2020 1 次提交
  5. 10 7月, 2020 2 次提交
  7. 07 7月, 2020 2 次提交
  9. 06 7月, 2020 4 次提交
  11. 09 6月, 2020 3 次提交
    • M
      KVM: arm64: Remove host_cpu_context member from vcpu structure · 07da1ffa
      由 Marc Zyngier 提交于 
      For very long, we have kept this pointer back to the per-cpu
host state, despite having working per-cpu accessors at EL2
for some time now.

Recent investigations have shown that this pointer is easy
to abuse in preemptible context, which is a sure sign that
it would better be gone. Not to mention that a per-cpu
pointer is faster to access at all times.
Reported-by: NAndrew Scull <ascull@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com
Reviewed-by: NAndrew Scull <ascull@google.com>
Signed-off-by: NMarc Zyngier <maz@kernel.org>
      07da1ffa
    • M
      KVM: arm64: Handle PtrAuth traps early · 29eb5a3c
      由 Marc Zyngier 提交于 
      The current way we deal with PtrAuth is a bit heavy handed:

- We forcefully save the host's keys on each vcpu_load()
- Handling the PtrAuth trap forces us to go all the way back
  to the exit handling code to just set the HCR bits

Overall, this is pretty cumbersome. A better approach would be
to handle it the same way we deal with the FPSIMD registers:

- On vcpu_load() disable PtrAuth for the guest
- On first use, save the host's keys, enable PtrAuth in the
  guest

Crucially, this can happen as a fixup, which is done very early
on exit. We can then reenter the guest immediately without
leaving the hypervisor role.

Another thing is that it simplify the rest of the host handling:
exiting all the way to the host means that the only possible
outcome for this trap is to inject an UNDEF.
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NMarc Zyngier <maz@kernel.org>
      29eb5a3c
    • M
      KVM: arm64: Save the host's PtrAuth keys in non-preemptible context · ef3e40a7
      由 Marc Zyngier 提交于 
      When using the PtrAuth feature in a guest, we need to save the host's
keys before allowing the guest to program them. For that, we dump
them in a per-CPU data structure (the so called host context).

But both call sites that do this are in preemptible context,
which may end up in disaster should the vcpu thread get preempted
before reentering the guest.

Instead, save the keys eagerly on each vcpu_load(). This has an
increased overhead, but is at least safe.

Cc: stable@vger.kernel.org
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NMarc Zyngier <maz@kernel.org>
      ef3e40a7
  13. 04 6月, 2020 1 次提交
    • P
      KVM: let kvm_destroy_vm_debugfs clean up vCPU debugfs directories · d56f5136
      由 Paolo Bonzini 提交于 
      After commit 63d04348 ("KVM: x86: move kvm_create_vcpu_debugfs after
last failure point") we are creating the pre-vCPU debugfs files
after the creation of the vCPU file descriptor.  This makes it
possible for userspace to reach kvm_vcpu_release before
kvm_create_vcpu_debugfs has finished.  The vcpu->debugfs_dentry
then does not have any associated inode anymore, and this causes
a NULL-pointer dereference in debugfs_create_file.

The solution is simply to avoid removing the files; they are
cleaned up when the VM file descriptor is closed (and that must be
after KVM_CREATE_VCPU returns).  We can stop storing the dentry
in struct kvm_vcpu too, because it is not needed anywhere after
kvm_create_vcpu_debugfs returns.

Reported-by: syzbot+705f4401d5a93a59b87d@syzkaller.appspotmail.com
Fixes: 63d04348 ("KVM: x86: move kvm_create_vcpu_debugfs after last failure point")
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      d56f5136
  15. 31 5月, 2020 1 次提交
  17. 25 5月, 2020 1 次提交
  19. 16 5月, 2020 4 次提交
  21. 14 5月, 2020 1 次提交
    • D
      kvm: Replace vcpu->swait with rcuwait · da4ad88c
      由 Davidlohr Bueso 提交于 
      The use of any sort of waitqueue (simple or regular) for
wait/waking vcpus has always been an overkill and semantically
wrong. Because this is per-vcpu (which is blocked) there is
only ever a single waiting vcpu, thus no need for any sort of
queue.

As such, make use of the rcuwait primitive, with the following
considerations:

  - rcuwait already provides the proper barriers that serialize
  concurrent waiter and waker.

  - Task wakeup is done in rcu read critical region, with a
  stable task pointer.

  - Because there is no concurrency among waiters, we need
  not worry about rcuwait_wait_event() calls corrupting
  the wait->task. As a consequence, this saves the locking
  done in swait when modifying the queue. This also applies
  to per-vcore wait for powerpc kvm-hv.

The x86 tscdeadline_latency test mentioned in 8577370f
("KVM: Use simple waitqueue for vcpu->wq") shows that, on avg,
latency is reduced by around 15-20% with this change.

Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-mips@vger.kernel.org
Reviewed-by: NMarc Zyngier <maz@kernel.org>
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-6-dave@stgolabs.net>
[Avoid extra logic changes. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      da4ad88c
  23. 21 4月, 2020 1 次提交
  25. 31 3月, 2020 1 次提交
  27. 24 3月, 2020 1 次提交
  29. 17 3月, 2020 1 次提交
    • S
      KVM: Provide common implementation for generic dirty log functions · 0dff0846
      由 Sean Christopherson 提交于 
      Move the implementations of KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG
for CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT into common KVM code.
The arch specific implemenations are extremely similar, differing
only in whether the dirty log needs to be sync'd from hardware (x86)
and how the TLBs are flushed.  Add new arch hooks to handle sync
and TLB flush; the sync will also be used for non-generic dirty log
support in a future patch (s390).

The ulterior motive for providing a common implementation is to
eliminate the dependency between arch and common code with respect to
the memslot referenced by the dirty log, i.e. to make it obvious in the
code that the validity of the memslot is guaranteed, as a future patch
will rework memslot handling such that id_to_memslot() can return NULL.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      0dff0846
  31. 17 2月, 2020 1 次提交
  33. 28 1月, 2020 5 次提交
  35. 24 1月, 2020 3 次提交
  37. 20 1月, 2020 2 次提交
  39. 06 12月, 2019 1 次提交