diff options
| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-11-02 11:54:46 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-11-07 15:44:04 +0100 |
| commit | b5bbf10ee6b65b70c10c139822bc2dc077cefa76 (patch) | |
| tree | a0a2290fb8abe5cf8feed46117a2876886bb4702 /arch/x86/kvm | |
| parent | 82b32774c2d00c0a12ab182c67e32e0b5e5e580a (diff) | |
KVM: x86: Emulation of MOV-sreg to memory uses incorrect size
In x86, you can only MOV-sreg to memory with either 16-bits or 64-bits size.
In contrast, KVM may write to 32-bits memory on MOV-sreg. This patch fixes KVM
behavior, and sets the destination operand size to two, if the destination is
memory.
When destination is registers, and the operand size is 32-bits, the high
16-bits in modern CPUs is filled with zero. This is handled correctly.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 736a49f218ff..713295d913fd 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3207,6 +3207,8 @@ static int em_mov_rm_sreg(struct x86_emulate_ctxt *ctxt) return emulate_ud(ctxt); ctxt->dst.val = get_segment_selector(ctxt, ctxt->modrm_reg); + if (ctxt->dst.bytes == 4 && ctxt->dst.type == OP_MEM) + ctxt->dst.bytes = 2; return X86EMUL_CONTINUE; } |