[PATCH 0/2] KVM: nVMX: Don't clobber VM-Entry instruction length on soft INTn exits

[ma . mandourr]

From: Mahmoud Abumandour <ma.mandourr@xxxxxxxxx>

KVM writes the length of a soft INTn that L2 was vectoring at the time of
a nested VM-Exit into vmcs12's VM-Entry instruction length, an L1-owned
control, instead of the VM-Exit instruction length.  Patch 1 fixes it and
patch 2 adds a selftest.

Found with a fuzzer for VMX isolation. The selftest patch was written with
the help of an LLM coding assistant (Claude Opus 5.5). kvm-x86/next was
run as a nested hypervisor under QEMU. The selftest passes only with
patch 1, and other nested VMX selftests are unaffected.

Mahmoud Abumandour (2):
  KVM: nVMX: Don't clobber VM-Entry instruction length when saving soft
    INTn
  KVM: selftests: Add test for nested VM-Exits while vectoring soft INTs

 arch/x86/kvm/vmx/nested.c                     |   2 +-
 tools/testing/selftests/kvm/Makefile.kvm      |   1 +
 .../kvm/x86/vmx_soft_int_vectoring_test.c     | 105 ++++++++++++++++++
 3 files changed, 107 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/kvm/x86/vmx_soft_int_vectoring_test.c


base-commit: dea4f6380f4ec96e8f3b0aaf2343764bd0d25ef4
-- 
2.43.0