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authorAvi Kivity <avi@qumranet.com>2007-01-22 20:40:40 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-01-23 07:52:06 -0800
commit038e51de2e7ae2c8e9d8a0b15231f8509875dc33 (patch)
treeb74e9b4c8c088c0e85f91cc91d64ce20ef5066a6
parentcccf748b810832cfab4dbb3ed4c7cf1a1ee35ad2 (diff)
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[PATCH] KVM: x86 emulator: fix bit string instructions
The various bit string instructions (bts, btc, etc.) fail to adjust the address correctly if the bit address is beyond BITS_PER_LONG. This bug creeped in as the emulator originally relied on cr2 to contain the memory address; however we now decode it from the mod r/m bits, and must adjust the offset to account for large bit indices. The patch is rather large because it switches src and dst decoding around, so that the bit index is available when decoding the memory address. This fixes workloads like the FC5 installer. Signed-off-by: Avi Kivity <avi@qumranet.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/kvm/x86_emulate.c98
1 files changed, 52 insertions, 46 deletions
diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index be70795b482..7513cddb929 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -61,6 +61,7 @@
#define ModRM (1<<6)
/* Destination is only written; never read. */
#define Mov (1<<7)
+#define BitOp (1<<8)
static u8 opcode_table[256] = {
/* 0x00 - 0x07 */
@@ -148,7 +149,7 @@ static u8 opcode_table[256] = {
0, 0, ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM
};
-static u8 twobyte_table[256] = {
+static u16 twobyte_table[256] = {
/* 0x00 - 0x0F */
0, SrcMem | ModRM | DstReg, 0, 0, 0, 0, ImplicitOps, 0,
0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0,
@@ -180,16 +181,16 @@ static u8 twobyte_table[256] = {
/* 0x90 - 0x9F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 0xA0 - 0xA7 */
- 0, 0, 0, DstMem | SrcReg | ModRM, 0, 0, 0, 0,
+ 0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
/* 0xA8 - 0xAF */
- 0, 0, 0, DstMem | SrcReg | ModRM, 0, 0, 0, 0,
+ 0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
/* 0xB0 - 0xB7 */
ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, 0,
- DstMem | SrcReg | ModRM,
+ DstMem | SrcReg | ModRM | BitOp,
0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,
DstReg | SrcMem16 | ModRM | Mov,
/* 0xB8 - 0xBF */
- 0, 0, DstMem | SrcImmByte | ModRM, DstMem | SrcReg | ModRM,
+ 0, 0, DstMem | SrcImmByte | ModRM, DstMem | SrcReg | ModRM | BitOp,
0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,
DstReg | SrcMem16 | ModRM | Mov,
/* 0xC0 - 0xCF */
@@ -469,7 +470,8 @@ static int read_descriptor(struct x86_emulate_ctxt *ctxt,
int
x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
- u8 b, d, sib, twobyte = 0, rex_prefix = 0;
+ unsigned d;
+ u8 b, sib, twobyte = 0, rex_prefix = 0;
u8 modrm, modrm_mod = 0, modrm_reg = 0, modrm_rm = 0;
unsigned long *override_base = NULL;
unsigned int op_bytes, ad_bytes, lock_prefix = 0, rep_prefix = 0, i;
@@ -726,46 +728,6 @@ done_prefixes:
;
}
- /* Decode and fetch the destination operand: register or memory. */
- switch (d & DstMask) {
- case ImplicitOps:
- /* Special instructions do their own operand decoding. */
- goto special_insn;
- case DstReg:
- dst.type = OP_REG;
- if ((d & ByteOp)
- && !(twobyte_table && (b == 0xb6 || b == 0xb7))) {
- dst.ptr = decode_register(modrm_reg, _regs,
- (rex_prefix == 0));
- dst.val = *(u8 *) dst.ptr;
- dst.bytes = 1;
- } else {
- dst.ptr = decode_register(modrm_reg, _regs, 0);
- switch ((dst.bytes = op_bytes)) {
- case 2:
- dst.val = *(u16 *)dst.ptr;
- break;
- case 4:
- dst.val = *(u32 *)dst.ptr;
- break;
- case 8:
- dst.val = *(u64 *)dst.ptr;
- break;
- }
- }
- break;
- case DstMem:
- dst.type = OP_MEM;
- dst.ptr = (unsigned long *)cr2;
- dst.bytes = (d & ByteOp) ? 1 : op_bytes;
- if (!(d & Mov) && /* optimisation - avoid slow emulated read */
- ((rc = ops->read_emulated((unsigned long)dst.ptr,
- &dst.val, dst.bytes, ctxt)) != 0))
- goto done;
- break;
- }
- dst.orig_val = dst.val;
-
/*
* Decode and fetch the source operand: register, memory
* or immediate.
@@ -838,6 +800,50 @@ done_prefixes:
break;
}
+ /* Decode and fetch the destination operand: register or memory. */
+ switch (d & DstMask) {
+ case ImplicitOps:
+ /* Special instructions do their own operand decoding. */
+ goto special_insn;
+ case DstReg:
+ dst.type = OP_REG;
+ if ((d & ByteOp)
+ && !(twobyte_table && (b == 0xb6 || b == 0xb7))) {
+ dst.ptr = decode_register(modrm_reg, _regs,
+ (rex_prefix == 0));
+ dst.val = *(u8 *) dst.ptr;
+ dst.bytes = 1;
+ } else {
+ dst.ptr = decode_register(modrm_reg, _regs, 0);
+ switch ((dst.bytes = op_bytes)) {
+ case 2:
+ dst.val = *(u16 *)dst.ptr;
+ break;
+ case 4:
+ dst.val = *(u32 *)dst.ptr;
+ break;
+ case 8:
+ dst.val = *(u64 *)dst.ptr;
+ break;
+ }
+ }
+ break;
+ case DstMem:
+ dst.type = OP_MEM;
+ dst.ptr = (unsigned long *)cr2;
+ dst.bytes = (d & ByteOp) ? 1 : op_bytes;
+ if (d & BitOp) {
+ dst.ptr += src.val / BITS_PER_LONG;
+ dst.bytes = sizeof(long);
+ }
+ if (!(d & Mov) && /* optimisation - avoid slow emulated read */
+ ((rc = ops->read_emulated((unsigned long)dst.ptr,
+ &dst.val, dst.bytes, ctxt)) != 0))
+ goto done;
+ break;
+ }
+ dst.orig_val = dst.val;
+
if (twobyte)
goto twobyte_insn;