KVM: SVM: Skip SEV cache flush if no ASIDs have been used
Skip SEV's expensive WBINVD and DF_FLUSH if there are no SEV ASIDs
waiting to be reclaimed, e.g. if SEV was never used. This "fixes" an
issue where the DF_FLUSH fails during hardware teardown if the original
SEV_INIT failed. Ideally, SEV wouldn't be marked as enabled in KVM if
SEV_INIT fails, but that's a problem for another day.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20210422021125.3417167-16-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>