[PATCH v2 21/26] KVM: x86 emulator: emulate BSWAP

Avi Kivity
2012-06-27T15:20:21Z

Opcodes 0F C8 - 0F CF.

Used by the SeaBIOS cdrom code (though not in big real mode).

Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/emulate.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b4b326e..cfa5cc3 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3264,6 +3264,21 @@ static int em_lahf(struct x86_emulate_ctxt *ctxt)
return X86EMUL_CONTINUE;
}

+static int em_bswap(struct x86_emulate_ctxt *ctxt)
+{
+ switch (ctxt->op_bytes) {
+#ifdef CONFIG_X86_64
+ case 8:
+ asm("bswap %0" : "+r"(ctxt->dst.val));
+ break;
+#endif
+ default:
+ asm("bswap %0" : "+r"(*(u32 *)&ctxt->dst.val));
+ break;
+ }
+ return X86EMUL_CONTINUE;
+}
+
static bool valid_cr(int nr)
{
switch (nr) {
@@ -3780,11 +3795,12 @@ static int check_perm_out(struct x86_emulate_ctxt *ctxt)
I(DstMem | SrcReg | ModRM | BitOp | Lock | PageTable, em_btc),
I(DstReg | SrcMem | ModRM, em_bsf), I(DstReg | SrcMem | ModRM, em_bsr),
D(DstReg | SrcMem8 | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
- /* 0xC0 - 0xCF */
+ /* 0xC0 - 0xC7 */
D2bv(DstMem | SrcReg | ModRM | Lock),
N, D(DstMem | SrcReg | ModRM | Mov),
N, N, N, GD(0, &group9),
- N, N, N, N, N, N, N, N,
+ /* 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,
/* 0xE0 - 0xEF */
--
1.7.11