Re: [PATCH 0/2] KVM: x86: Rep string I/O WARN removal and test

From: Paolo Bonzini
Date: Thu Dec 09 2021 - 06:22:55 EST


On 12/9/21 06:48, Sean Christopherson wrote:
On Mon, Oct 25, 2021, Sean Christopherson wrote:
Remove a WARN that was added as part of the recent I/O overhaul to play
nice with SEV-ES string I/O.

For the record, my FIXME in lieu of a WARN was deliberate, as I suspected
userspace could trigger a WARN ;-)

Based on kvm/master, commit 95e16b4792b0 ("KVM: SEV-ES: go over the
sev_pio_data buffer in multiple passes if needed").

Sean Christopherson (2):
KVM: x86: Don't WARN if userspace mucks with RCX during string I/O
exit
KVM: selftests: Add test to verify KVM doesn't explode on "bad" I/O

arch/x86/kvm/x86.c | 9 +-
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/x86_64/userspace_io_test.c | 114 ++++++++++++++++++
4 files changed, 123 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/kvm/x86_64/userspace_io_test.c

Ping. I completely forgot about this too, until I unintentionally ran a
userspace_io_test that was lying around.


Queued now, thanks. I don't know if I want the honor of having KVM singled out again on the -rc release message, but these are bugs nevertheless...

Paolo