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Subject[PATCH 8/9] KVM: x86: Return error on cmpxchg16b emulation
Date
cmpxchg16b is currently unimplemented in the emulator. The least we can do is
return error upon the emulation of this instruction.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
---
arch/x86/kvm/emulate.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 3da8d82..a151f8d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1999,6 +1999,9 @@ static int em_cmpxchg8b(struct x86_emulate_ctxt *ctxt)
{
u64 old = ctxt->dst.orig_val64;

+ if (ctxt->dst.bytes == 16)
+ return X86EMUL_UNHANDLEABLE;
+
if (((u32) (old >> 0) != (u32) reg_read(ctxt, VCPU_REGS_RAX)) ||
((u32) (old >> 32) != (u32) reg_read(ctxt, VCPU_REGS_RDX))) {
*reg_write(ctxt, VCPU_REGS_RAX) = (u32) (old >> 0);
@@ -4077,7 +4080,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
op->orig_val = op->val;
break;
case OpMem64:
- ctxt->memop.bytes = 8;
+ ctxt->memop.bytes = (ctxt->op_bytes == 8) ? 16 : 8;
goto mem_common;
case OpAcc:
op->type = OP_REG;
--
1.9.1


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