diff options
| -rw-r--r-- | arch/x86/kvm/emulate.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 53c5ad6851d1..dd71567d7c71 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -149,6 +149,7 @@ #define Aligned ((u64)1 << 41) /* Explicitly aligned (e.g. MOVDQA) */ #define Unaligned ((u64)1 << 42) /* Explicitly unaligned (e.g. MOVDQU) */ #define Avx ((u64)1 << 43) /* Advanced Vector Extensions */ +#define Fastop ((u64)1 << 44) /* Use opcode::u.fastop */ #define X2(x...) x, x #define X3(x...) X2(x), x @@ -159,6 +160,27 @@ #define X8(x...) X4(x), X4(x) #define X16(x...) X8(x), X8(x) +#define NR_FASTOP (ilog2(sizeof(ulong)) + 1) +#define FASTOP_SIZE 8 + +/* + * fastop functions have a special calling convention: + * + * dst: [rdx]:rax (in/out) + * src: rbx (in/out) + * src2: rcx (in) + * flags: rflags (in/out) + * + * Moreover, they are all exactly FASTOP_SIZE bytes long, so functions for + * different operand sizes can be reached by calculation, rather than a jump + * table (which would be bigger than the code). + * + * fastop functions are declared as taking a never-defined fastop parameter, + * so they can't be called from C directly. + */ + +struct fastop; + struct opcode { u64 flags : 56; u64 intercept : 8; @@ -168,6 +190,7 @@ struct opcode { const struct group_dual *gdual; const struct gprefix *gprefix; const struct escape *esc; + void (*fastop)(struct fastop *fake); } u; int (*check_perm)(struct x86_emulate_ctxt *ctxt); }; @@ -3646,6 +3669,7 @@ static int check_perm_out(struct x86_emulate_ctxt *ctxt) #define GD(_f, _g) { .flags = ((_f) | GroupDual | ModRM), .u.gdual = (_g) } #define E(_f, _e) { .flags = ((_f) | Escape | ModRM), .u.esc = (_e) } #define I(_f, _e) { .flags = (_f), .u.execute = (_e) } +#define F(_f, _e) { .flags = (_f) | Fastop, .u.fastop = (_e) } #define II(_f, _e, _i) \ { .flags = (_f), .u.execute = (_e), .intercept = x86_intercept_##_i } #define IIP(_f, _e, _i, _p) \ @@ -4502,6 +4526,16 @@ static void fetch_possible_mmx_operand(struct x86_emulate_ctxt *ctxt, read_mmx_reg(ctxt, &op->mm_val, op->addr.mm); } +static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)) +{ + ulong flags = (ctxt->eflags & EFLAGS_MASK) | X86_EFLAGS_IF; + fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE; + asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n" + : "+a"(ctxt->dst.val), "+b"(ctxt->src.val), [flags]"+D"(flags) + : "c"(ctxt->src2.val), [fastop]"S"(fop)); + ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK); + return X86EMUL_CONTINUE; +} int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) { @@ -4631,6 +4665,13 @@ special_insn: } if (ctxt->execute) { + if (ctxt->d & Fastop) { + void (*fop)(struct fastop *) = (void *)ctxt->execute; + rc = fastop(ctxt, fop); + if (rc != X86EMUL_CONTINUE) + goto done; + goto writeback; + } rc = ctxt->execute(ctxt); if (rc != X86EMUL_CONTINUE) goto done; |