KVM: x86 emulator: refuse SrcMemFAddr (e.g. LDS) with register operand

SrcMemFAddr is not defined with the modrm operand designating a register
instead of a memory address.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index ec35a71d8b5d155c2bf015c5d82c848ff94c09e0..2b9b0feabdba934622d2fac014dcb73d309e16bf 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2974,6 +2974,11 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
                goto done;
        }
 
+       if ((c->d & SrcMask) == SrcMemFAddr && c->src.type != OP_MEM) {
+               emulate_ud(ctxt);
+               goto done;
+       }
+
        /* Privileged instruction can be executed only in CPL=0 */
        if ((c->d & Priv) && ops->cpl(ctxt->vcpu)) {
                emulate_gp(ctxt, 0);