3.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
commit a035d5c64d08a8ac12d81b596e7fa6d95a73c347 upstream.
This is used by SGABIOS, KVM breaks with emulate_invalid_guest_state=1.
AAM needs the source operand to be unsigned; do the same in AAD as well
for consistency, even though it does not affect the result.
Reported-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2986,6 +2986,28 @@ static int em_das(struct x86_emulate_ctx
return X86EMUL_CONTINUE;
}
+static int em_aam(struct x86_emulate_ctxt *ctxt)
+{
+ u8 al, ah;
+
+ if (ctxt->src.val == 0)
+ return emulate_de(ctxt);
+
+ al = ctxt->dst.val & 0xff;
+ ah = al / ctxt->src.val;
+ al %= ctxt->src.val;
+
+ ctxt->dst.val = (ctxt->dst.val & 0xffff0000) | al | (ah << 8);
+
+ /* Set PF, ZF, SF */
+ ctxt->src.type = OP_IMM;
+ ctxt->src.val = 0;
+ ctxt->src.bytes = 1;
+ fastop(ctxt, em_or);
+
+ return X86EMUL_CONTINUE;
+}
+
static int em_aad(struct x86_emulate_ctxt *ctxt)
{
u8 al = ctxt->dst.val & 0xff;
@@ -3926,7 +3948,8 @@ static const struct opcode opcode_table[
/* 0xD0 - 0xD7 */
G(Src2One | ByteOp, group2), G(Src2One, group2),
G(Src2CL | ByteOp, group2), G(Src2CL, group2),
- N, I(DstAcc | SrcImmByte | No64, em_aad), N, N,
+ I(DstAcc | SrcImmUByte | No64, em_aam),
+ I(DstAcc | SrcImmUByte | No64, em_aad), N, N,
/* 0xD8 - 0xDF */
N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N,
/* 0xE0 - 0xE7 */
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