diff options
| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-06-15 15:13:01 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-06-19 12:52:10 +0200 |
| commit | a825f5cc4a8455663562809748240169cb9bc2c0 (patch) | |
| tree | 17ea2adbf49880c35c630268b7eaa01dfe35bfed /arch | |
| parent | KVM: x86: emulation of dword cmov on long-mode should clear [63:32] (diff) | |
| download | linux-a825f5cc4a8455663562809748240169cb9bc2c0.tar.xz linux-a825f5cc4a8455663562809748240169cb9bc2c0.zip | |
KVM: x86: NOP emulation clears (incorrectly) the high 32-bits of RAX
On long-mode the current NOP (0x90) emulation still writes back to RAX. As a
result, EAX is zero-extended and the high 32-bits of RAX are cleared.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 6f09b2e555ef..84dc4ba0364d 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4688,8 +4688,9 @@ special_insn: break; case 0x90 ... 0x97: /* nop / xchg reg, rax */ if (ctxt->dst.addr.reg == reg_rmw(ctxt, VCPU_REGS_RAX)) - break; - rc = em_xchg(ctxt); + ctxt->dst.type = OP_NONE; + else + rc = em_xchg(ctxt); break; case 0x98: /* cbw/cwde/cdqe */ switch (ctxt->op_bytes) { |