From: Mihai Donțu <mdo...@bitdefender.com>

This is needed in order to be able to support guest code that uses movq to
write into pages that are marked for write tracking.

Signed-off-by: Mihai Donțu <mdo...@bitdefender.com>
Signed-off-by: Adalbert Lazăr <ala...@bitdefender.com>
---
 arch/x86/kvm/emulate.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b8a412b8b087..2297955d0934 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1180,23 +1180,24 @@ static int em_fnstsw(struct x86_emulate_ctxt *ctxt)
 static u8 simd_prefix_to_bytes(const struct x86_emulate_ctxt *ctxt,
                               int simd_prefix)
 {
-       u8 bytes;
+       u8 bytes = 16;
 
        switch (ctxt->b) {
        case 0x11:
                /* movss xmm, m32 */
                /* movsd xmm, m64 */
                /* movups xmm, m128 */
-               if (simd_prefix == 0xf3) {
+               if (simd_prefix == 0xf3)
                        bytes = 4;
-                       break;
-               } else if (simd_prefix == 0xf2) {
+               else if (simd_prefix == 0xf2)
                        bytes = 8;
-                       break;
-               }
-               /* fallthrough */
+               break;
+       case 0xd6:
+               /* movq xmm, m64 */
+               if (simd_prefix == 0x66)
+                       bytes = 8;
+               break;
        default:
-               bytes = 16;
                break;
        }
        return bytes;
@@ -4549,6 +4550,10 @@ static const struct instr_dual instr_dual_0f_2b = {
        I(0, em_mov), N
 };
 
+static const struct gprefix pfx_0f_d6 = {
+       N, I(0, em_mov), N, N,
+};
+
 static const struct gprefix pfx_0f_2b = {
        ID(0, &instr_dual_0f_2b), ID(0, &instr_dual_0f_2b), N, N,
 };
@@ -4846,7 +4851,8 @@ static const struct opcode twobyte_table[256] = {
        /* 0xC8 - 0xCF */
        X8(I(DstReg, em_bswap)),
        /* 0xD0 - 0xDF */
-       N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N,
+       N, N, N, N, N, N, GP(ModRM | SrcReg | DstMem | Mov | Sse, &pfx_0f_d6),
+       N, N, N, N, N, N, N, N, N,
        /* 0xE0 - 0xEF */
        N, N, N, N, N, N, N, GP(SrcReg | DstMem | ModRM | Mov, &pfx_0f_e7),
        N, N, N, N, N, N, N, N,
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