KVM: VMX: Execute WBINVD to keep data consistency with assigned devices

Some guest device driver may leverage the "Non-Snoop" I/O, and explicitly
WBINVD or CLFLUSH to a RAM space. Since migration may occur before WBINVD or
CLFLUSH, we need to maintain data consistency either by:
1: flushing cache (wbinvd) when the guest is scheduled out if there is no
wbinvd exit, or
2: execute wbinvd on all dirty physical CPUs when guest wbinvd exits.

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index abb8cec420a2..e8bdddc4509e 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3138,8 +3138,11 @@ twobyte_insn:
                 emulate_clts(ctxt->vcpu);
                 c->dst.type = OP_NONE;
                 break;
-        case 0x08:              /* invd */
         case 0x09:              /* wbinvd */
+                kvm_emulate_wbinvd(ctxt->vcpu);
+                c->dst.type = OP_NONE;
+                break;
+        case 0x08:              /* invd */
         case 0x0d:              /* GrpP (prefetch) */
         case 0x18:              /* Grp16 (prefetch/nop) */
                 c->dst.type = OP_NONE;