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Diffstat (limited to 'arch/x86/kvm/emulate.c')
-rw-r--r--arch/x86/kvm/emulate.c130
1 files changed, 107 insertions, 23 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index ddc3f3d2afdb..07ffca0a89e9 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -130,7 +130,7 @@
#define Mov (1<<20)
/* Misc flags */
#define Prot (1<<21) /* instruction generates #UD if not in prot-mode */
-#define VendorSpecific (1<<22) /* Vendor specific instruction */
+#define EmulateOnUD (1<<22) /* Emulate if unsupported by the host */
#define NoAccess (1<<23) /* Don't access memory (lea/invlpg/verr etc) */
#define Op3264 (1<<24) /* Operand is 64b in long mode, 32b otherwise */
#define Undefined (1<<25) /* No Such Instruction */
@@ -785,9 +785,10 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
* @highbyte_regs specifies whether to decode AH,CH,DH,BH.
*/
static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg,
- int highbyte_regs)
+ int byteop)
{
void *p;
+ int highbyte_regs = (ctxt->rex_prefix == 0) && byteop;
if (highbyte_regs && modrm_reg >= 4 && modrm_reg < 8)
p = (unsigned char *)reg_rmw(ctxt, modrm_reg & 3) + 1;
@@ -1024,7 +1025,6 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
struct operand *op)
{
unsigned reg = ctxt->modrm_reg;
- int highbyte_regs = ctxt->rex_prefix == 0;
if (!(ctxt->d & ModRM))
reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3);
@@ -1045,13 +1045,9 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
}
op->type = OP_REG;
- if (ctxt->d & ByteOp) {
- op->addr.reg = decode_register(ctxt, reg, highbyte_regs);
- op->bytes = 1;
- } else {
- op->addr.reg = decode_register(ctxt, reg, 0);
- op->bytes = ctxt->op_bytes;
- }
+ op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
+ op->addr.reg = decode_register(ctxt, reg, ctxt->d & ByteOp);
+
fetch_register_operand(op);
op->orig_val = op->val;
}
@@ -1082,12 +1078,10 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
ctxt->modrm_seg = VCPU_SREG_DS;
if (ctxt->modrm_mod == 3) {
- int highbyte_regs = ctxt->rex_prefix == 0;
-
op->type = OP_REG;
op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
op->addr.reg = decode_register(ctxt, ctxt->modrm_rm,
- highbyte_regs && (ctxt->d & ByteOp));
+ ctxt->d & ByteOp);
if (ctxt->d & Sse) {
op->type = OP_XMM;
op->bytes = 16;
@@ -2961,6 +2955,46 @@ static int em_mov(struct x86_emulate_ctxt *ctxt)
return X86EMUL_CONTINUE;
}
+#define FFL(x) bit(X86_FEATURE_##x)
+
+static int em_movbe(struct x86_emulate_ctxt *ctxt)
+{
+ u32 ebx, ecx, edx, eax = 1;
+ u16 tmp;
+
+ /*
+ * Check MOVBE is set in the guest-visible CPUID leaf.
+ */
+ ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx);
+ if (!(ecx & FFL(MOVBE)))
+ return emulate_ud(ctxt);
+
+ switch (ctxt->op_bytes) {
+ case 2:
+ /*
+ * From MOVBE definition: "...When the operand size is 16 bits,
+ * the upper word of the destination register remains unchanged
+ * ..."
+ *
+ * Both casting ->valptr and ->val to u16 breaks strict aliasing
+ * rules so we have to do the operation almost per hand.
+ */
+ tmp = (u16)ctxt->src.val;
+ ctxt->dst.val &= ~0xffffUL;
+ ctxt->dst.val |= (unsigned long)swab16(tmp);
+ break;
+ case 4:
+ ctxt->dst.val = swab32((u32)ctxt->src.val);
+ break;
+ case 8:
+ ctxt->dst.val = swab64(ctxt->src.val);
+ break;
+ default:
+ return X86EMUL_PROPAGATE_FAULT;
+ }
+ return X86EMUL_CONTINUE;
+}
+
static int em_cr_write(struct x86_emulate_ctxt *ctxt)
{
if (ctxt->ops->set_cr(ctxt, ctxt->modrm_reg, ctxt->src.val))
@@ -3256,6 +3290,18 @@ static int em_cpuid(struct x86_emulate_ctxt *ctxt)
return X86EMUL_CONTINUE;
}
+static int em_sahf(struct x86_emulate_ctxt *ctxt)
+{
+ u32 flags;
+
+ flags = EFLG_CF | EFLG_PF | EFLG_AF | EFLG_ZF | EFLG_SF;
+ flags &= *reg_rmw(ctxt, VCPU_REGS_RAX) >> 8;
+
+ ctxt->eflags &= ~0xffUL;
+ ctxt->eflags |= flags | X86_EFLAGS_FIXED;
+ return X86EMUL_CONTINUE;
+}
+
static int em_lahf(struct x86_emulate_ctxt *ctxt)
{
*reg_rmw(ctxt, VCPU_REGS_RAX) &= ~0xff00UL;
@@ -3502,7 +3548,7 @@ static const struct opcode group7_rm1[] = {
static const struct opcode group7_rm3[] = {
DIP(SrcNone | Prot | Priv, vmrun, check_svme_pa),
- II(SrcNone | Prot | VendorSpecific, em_vmmcall, vmmcall),
+ II(SrcNone | Prot | EmulateOnUD, em_vmmcall, vmmcall),
DIP(SrcNone | Prot | Priv, vmload, check_svme_pa),
DIP(SrcNone | Prot | Priv, vmsave, check_svme_pa),
DIP(SrcNone | Prot | Priv, stgi, check_svme),
@@ -3587,7 +3633,7 @@ static const struct group_dual group7 = { {
II(SrcMem16 | Mov | Priv, em_lmsw, lmsw),
II(SrcMem | ByteOp | Priv | NoAccess, em_invlpg, invlpg),
}, {
- I(SrcNone | Priv | VendorSpecific, em_vmcall),
+ I(SrcNone | Priv | EmulateOnUD, em_vmcall),
EXT(0, group7_rm1),
N, EXT(0, group7_rm3),
II(SrcNone | DstMem | Mov, em_smsw, smsw), N,
@@ -3750,7 +3796,8 @@ static const struct opcode opcode_table[256] = {
D(DstAcc | SrcNone), I(ImplicitOps | SrcAcc, em_cwd),
I(SrcImmFAddr | No64, em_call_far), N,
II(ImplicitOps | Stack, em_pushf, pushf),
- II(ImplicitOps | Stack, em_popf, popf), N, I(ImplicitOps, em_lahf),
+ II(ImplicitOps | Stack, em_popf, popf),
+ I(ImplicitOps, em_sahf), I(ImplicitOps, em_lahf),
/* 0xA0 - 0xA7 */
I2bv(DstAcc | SrcMem | Mov | MemAbs, em_mov),
I2bv(DstMem | SrcAcc | Mov | MemAbs | PageTable, em_mov),
@@ -3810,7 +3857,7 @@ static const struct opcode opcode_table[256] = {
static const struct opcode twobyte_table[256] = {
/* 0x00 - 0x0F */
G(0, group6), GD(0, &group7), N, N,
- N, I(ImplicitOps | VendorSpecific, em_syscall),
+ N, I(ImplicitOps | EmulateOnUD, em_syscall),
II(ImplicitOps | Priv, em_clts, clts), N,
DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N,
N, D(ImplicitOps | ModRM), N, N,
@@ -3830,8 +3877,8 @@ static const struct opcode twobyte_table[256] = {
IIP(ImplicitOps, em_rdtsc, rdtsc, check_rdtsc),
II(ImplicitOps | Priv, em_rdmsr, rdmsr),
IIP(ImplicitOps, em_rdpmc, rdpmc, check_rdpmc),
- I(ImplicitOps | VendorSpecific, em_sysenter),
- I(ImplicitOps | Priv | VendorSpecific, em_sysexit),
+ I(ImplicitOps | EmulateOnUD, em_sysenter),
+ I(ImplicitOps | Priv | EmulateOnUD, em_sysexit),
N, N,
N, N, N, N, N, N, N, N,
/* 0x40 - 0x4F */
@@ -3892,6 +3939,30 @@ static const struct opcode twobyte_table[256] = {
N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N
};
+static const struct gprefix three_byte_0f_38_f0 = {
+ I(DstReg | SrcMem | Mov, em_movbe), N, N, N
+};
+
+static const struct gprefix three_byte_0f_38_f1 = {
+ I(DstMem | SrcReg | Mov, em_movbe), N, N, N
+};
+
+/*
+ * Insns below are selected by the prefix which indexed by the third opcode
+ * byte.
+ */
+static const struct opcode opcode_map_0f_38[256] = {
+ /* 0x00 - 0x7f */
+ X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N),
+ /* 0x80 - 0xef */
+ X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N),
+ /* 0xf0 - 0xf1 */
+ GP(EmulateOnUD | ModRM | Prefix, &three_byte_0f_38_f0),
+ GP(EmulateOnUD | ModRM | Prefix, &three_byte_0f_38_f1),
+ /* 0xf2 - 0xff */
+ N, N, X4(N), X8(N)
+};
+
#undef D
#undef N
#undef G
@@ -4040,7 +4111,8 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
case OpMem8:
ctxt->memop.bytes = 1;
if (ctxt->memop.type == OP_REG) {
- ctxt->memop.addr.reg = decode_register(ctxt, ctxt->modrm_rm, 1);
+ ctxt->memop.addr.reg = decode_register(ctxt,
+ ctxt->modrm_rm, true);
fetch_register_operand(&ctxt->memop);
}
goto mem_common;
@@ -4126,6 +4198,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
ctxt->_eip = ctxt->eip;
ctxt->fetch.start = ctxt->_eip;
ctxt->fetch.end = ctxt->fetch.start + insn_len;
+ ctxt->opcode_len = 1;
if (insn_len > 0)
memcpy(ctxt->fetch.data, insn, insn_len);
@@ -4208,9 +4281,16 @@ done_prefixes:
opcode = opcode_table[ctxt->b];
/* Two-byte opcode? */
if (ctxt->b == 0x0f) {
- ctxt->twobyte = 1;
+ ctxt->opcode_len = 2;
ctxt->b = insn_fetch(u8, ctxt);
opcode = twobyte_table[ctxt->b];
+
+ /* 0F_38 opcode map */
+ if (ctxt->b == 0x38) {
+ ctxt->opcode_len = 3;
+ ctxt->b = insn_fetch(u8, ctxt);
+ opcode = opcode_map_0f_38[ctxt->b];
+ }
}
ctxt->d = opcode.flags;
@@ -4267,7 +4347,7 @@ done_prefixes:
if (ctxt->d == 0 || (ctxt->d & NotImpl))
return EMULATION_FAILED;
- if (!(ctxt->d & VendorSpecific) && ctxt->only_vendor_specific_insn)
+ if (!(ctxt->d & EmulateOnUD) && ctxt->ud)
return EMULATION_FAILED;
if (mode == X86EMUL_MODE_PROT64 && (ctxt->d & Stack))
@@ -4540,8 +4620,10 @@ special_insn:
goto writeback;
}
- if (ctxt->twobyte)
+ if (ctxt->opcode_len == 2)
goto twobyte_insn;
+ else if (ctxt->opcode_len == 3)
+ goto threebyte_insn;
switch (ctxt->b) {
case 0x63: /* movsxd */
@@ -4726,6 +4808,8 @@ twobyte_insn:
goto cannot_emulate;
}
+threebyte_insn:
+
if (rc != X86EMUL_CONTINUE)
goto done;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.