KVM: SEV: Document the SEV-ES check when querying SMM support as "safe"

Browse source

Use the "unsafe" API to check for an SEV-ES+ guest when determining whether
or not SMBASE is a supported MSR, i.e. whether or not emulated SMM is
supported.  This will eventually allow adding lockdep assertings to the
APIs for detecting SEV+ VMs without triggering "real" false positives.

While svm_has_emulated_msr() doesn't hold kvm->lock, i.e. can get both
false positives *and* false negatives, both are completely fine, as the
only time the result isn't stable is when userspace is the sole consumer
of the result.  I.e. userspace can confuse itself, but that's it.

No functional change intended.

Link: https://patch.msgid.link/20260310234829.2608037-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

...

This commit is contained in:

Sean Christopherson 2026-03-10 16:48:17 -07:00

parent 138e5f6a3e

commit 56906910ea

1 changed files with 10 additions and 2 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

12

arch/x86/kvm/svm/svm.c

View file