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[v2,0/4] KVM: arm64: Fix bugs of single-step execution enabled by userspace

Message ID 20220917010600.532642-1-reijiw@google.com (mailing list archive)
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Series KVM: arm64: Fix bugs of single-step execution enabled by userspace | expand

Message

Reiji Watanabe Sept. 17, 2022, 1:05 a.m. UTC
This series fixes two bugs of single-step execution enabled by
userspace, and add a test case for KVM_GUESTDBG_SINGLESTEP to
the debug-exception test to verify the single-step behavior.

Patch 1 fixes a bug that KVM might unintentionally change PSTATE.SS
for the guest when single-step execution is enabled for the vCPU by
userspace.

Patch 2 fixes a bug that KVM could erroneously perform an extra
single step (without returning to userspace) due to setting PSTATE.SS
to 1 on every guest entry, when single-step execution is enabled for
the vCPU by userspace.

Patch 3-4 adds a test for KVM_GUESTDBG_SINGLESTEP to the
debug-exception test to verify the single-step behavior.

The series is based on 6.0-rc5.

v2:
 - Change kvm_handle_guest_debug() to use switch/case statement [Marc]
 - Clear PSTATE.SS on guest entry if the Software step state at the
   last guest exit was "Active-pending" to make DBG_SS_ACTIVE_PENDING
   and PSTATE.SS consistent [Marc]
 - Add a fix to preserve PSTATE.SS for the guest.

v1: https://lore.kernel.org/all/20220909044636.1997755-1-reijiw@google.com/

Reiji Watanabe (4):
  KVM: arm64: Preserve PSTATE.SS for the guest while single-step is
    enabled
  KVM: arm64: Clear PSTATE.SS when the Software Step state was
    Active-pending
  KVM: arm64: selftests: Refactor debug-exceptions to make it amenable
    to new test cases
  KVM: arm64: selftests: Add a test case for KVM_GUESTDBG_SINGLESTEP

 arch/arm64/include/asm/kvm_host.h             |   4 +
 arch/arm64/kvm/debug.c                        |  34 +++-
 arch/arm64/kvm/guest.c                        |   1 +
 arch/arm64/kvm/handle_exit.c                  |   8 +-
 .../selftests/kvm/aarch64/debug-exceptions.c  | 149 +++++++++++++++++-
 5 files changed, 190 insertions(+), 6 deletions(-)


base-commit: 80e78fcce86de0288793a0ef0f6acf37656ee4cf

Comments

Marc Zyngier Sept. 19, 2022, 10:04 a.m. UTC | #1
On Fri, 16 Sep 2022 18:05:56 -0700, Reiji Watanabe wrote:
> This series fixes two bugs of single-step execution enabled by
> userspace, and add a test case for KVM_GUESTDBG_SINGLESTEP to
> the debug-exception test to verify the single-step behavior.
> 
> Patch 1 fixes a bug that KVM might unintentionally change PSTATE.SS
> for the guest when single-step execution is enabled for the vCPU by
> userspace.
> 
> [...]

Applied to next, thanks!

[1/4] KVM: arm64: Preserve PSTATE.SS for the guest while single-step is enabled
      commit: 34fbdee086cfcc20fe889d2b83afddfbe2ac3096
[2/4] KVM: arm64: Clear PSTATE.SS when the Software Step state was Active-pending
      commit: 370531d1e95be57c62fdf065fb04fd8db7ade8f9
[3/4] KVM: arm64: selftests: Refactor debug-exceptions to make it amenable to new test cases
      commit: ff00e737090e0f015059e59829aaa58565b16321
[4/4] KVM: arm64: selftests: Add a test case for KVM_GUESTDBG_SINGLESTEP
      commit: b18e4d4aebdddd05810ceb2f73d7f72afcd11b41

Cheers,

	M.