KVM: SVM: Refuse to attempt VRMUN if an SEV-ES+ guest has an invalid VMSA

Browse source

Explicitly reject KVM_RUN with KVM_EXIT_FAIL_ENTRY if userspace "coerces"
KVM into running an SEV-ES+ guest with an invalid VMSA, e.g. by modifying
a vCPU's mp_state to be RUNNABLE after an SNP vCPU has undergone a Destroy
event.  On Destroy or failed Create, KVM marks the vCPU HALTED so that
*KVM* doesn't run the vCPU, but nothing prevents a misbehaving VMM from
manually making the vCPU RUNNABLE via KVM_SET_MP_STATE.

Attempting VMRUN with an invalid VMSA should be harmless, but knowingly
executing VMRUN with bad control state is at best dodgy.

Fixes: e366f92ea9 ("KVM: SEV: Support SEV-SNP AP Creation NAE event")
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Link: https://lore.kernel.org/r/20250227012541.3234589-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

...

This commit is contained in:

Sean Christopherson 2025-02-26 17:25:34 -08:00

parent d4b69c3d14

commit 72d12715ed

3 changed files with 23 additions and 6 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

16

arch/x86/kvm/svm/sev.c

View file

11

arch/x86/kvm/svm/svm.c

View file

2

arch/x86/kvm/svm/svm.h

View file