Jim pointed out that VMRUN/VMLOAD/VMSAVE injecting a #GP when the vmcb12
GPA is valid but not mappable is not architectural [1]. The series
handles them as emulation failures and (mostly) exits to userspace
instead.
With vls=1, a VMSAVE/VMLOAD with an unmappable GPA will cause a #NPF and
be emulated. The emulator currently hardcodes the GPA check to 48 valid
bits and injects a #GP otherwise. Fix this to only inject a #GP if the
GPA actually exceeds maxphyaddr, and otherwise fail the emulation as
well.
Rework svm_nested_invalid_vmcb12_gpa to fix the fact that it's currently
testing #GP on VMLOAD instead of VMRUN, and extend it to test all of
VMRUN, VMLOAD, and VMSAVE in both cases of GPA > maxphyaddr and GPA <
maxphyaddr but unmappable. Finally rename it to make its name a bit more
generic and representative.
This is not strictly a v2, but it supersedes the series at [2].
[1]https://lore.kernel.org/kvm/CALMp9eSMtzDJn7tGtbj=zLYpcU7Tc7XjcWBRZH7Aa5YihSmN7g@mail.gmail.com/
[2]https://lore.kernel.org/kvm/20260305203005.1021335-1-yosry@kernel.org/
Yosry Ahmed (6):
KVM: SVM: Use maxphyaddr in emulator RAX check for VMRUN/VMLOAD/VMSAVE
KVM: nSVM: Simplify error handling of
nested_svm_copy_vmcb12_to_cache()
KVM: SVM: Treat mapping failures equally in VMLOAD/VMSAVE emulation
KVM: nSVM: Fail emulation of VMRUN/VMLOAD/VMSAVE if mapping vmcb12
fails
KVM: selftests: Rework svm_nested_invalid_vmcb12_gpa
KVM: selftests: Drop 'invalid' from svm_nested_invalid_vmcb12_gpa's
name
arch/x86/kvm/emulate.c | 3 +-
arch/x86/kvm/svm/nested.c | 20 +-
arch/x86/kvm/svm/svm.c | 8 +-
tools/testing/selftests/kvm/Makefile.kvm | 2 +-
.../testing/selftests/kvm/include/kvm_util.h | 1 +
tools/testing/selftests/kvm/lib/kvm_util.c | 6 +
.../kvm/x86/svm_nested_invalid_vmcb12_gpa.c | 98 ----------
.../selftests/kvm/x86/svm_nested_vmcb12_gpa.c | 179 ++++++++++++++++++
8 files changed, 200 insertions(+), 117 deletions(-)
delete mode 100644 tools/testing/selftests/kvm/x86/svm_nested_invalid_vmcb12_gpa.c
create mode 100644 tools/testing/selftests/kvm/x86/svm_nested_vmcb12_gpa.c
base-commit: 5128b972fb2801ad9aca54d990a75611ab5283a9
--
2.53.0.473.g4a7958ca14-goog