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. It also fixes the checks performed on the vmcb12 GPA (i.e. RAX)
in a few places.
v2 -> v3:
- Drop the patch simplifying error handling of
nested_svm_copy_vmcb12_to_cache() as it was picked up into
kvm-x86/next.
- Drop the legal GPA check on RAX in the emulator instead of fixing it
[Sean].
- Fix legal GPA check on RAX in the #GP interception path [Sean].
- Move legal GPA check to VMRUN/VMLOAD/VMSAVE interception handlers
[Yosry].
- Update the selftest to use the first GPA after memslots, rather than
the maximum legal GPA, as the unmappable GPA. This is needed because
the maximum legal GPA sometimes still produces a #GP if it's in a
reserved area [Yosry].
v2: https://lore.kernel.org/kvm/20260306210900.1933788-1-yosry@kernel.org/
Yosry Ahmed (7):
KVM: SVM: Drop RAX check for SVM instructions from the emulator
KVM: SVM: Check that RAX has legal GPA on #GP interception of SVM
insns
KVM: SVM: Move RAX legality check to SVM insn interception handlers
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 | 17 +-
arch/x86/kvm/svm/nested.c | 11 +-
arch/x86/kvm/svm/svm.c | 37 ++--
tools/testing/selftests/kvm/Makefile.kvm | 2 +-
.../kvm/x86/svm_nested_invalid_vmcb12_gpa.c | 98 ----------
.../selftests/kvm/x86/svm_nested_vmcb12_gpa.c | 176 ++++++++++++++++++
6 files changed, 203 insertions(+), 138 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: bfd7f4adc1230373c25e1b787a6f1ee407eb0656
--
2.53.0.851.ga537e3e6e9-goog