From cbe2c9d30aa69b0551247ddb0fb450b6e8080ec4 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Mon, 9 Apr 2012 18:40:02 +0300 Subject: [PATCH] KVM: x86 emulator: MMX support General support for the MMX instruction set. Special care is taken to trap pending x87 exceptions so that they are properly reflected to the guest. Signed-off-by: Avi Kivity Signed-off-by: Marcelo Tosatti --- arch/x86/include/asm/kvm_emulate.h | 4 +- arch/x86/kvm/emulate.c | 103 +++++++++++++++++++++++++++++++++++-- 2 files changed, 102 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index c222e1a..1ac46c22 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -200,7 +200,7 @@ typedef u32 __attribute__((vector_size(16))) sse128_t; /* Type, address-of, and value of an instruction's operand. */ struct operand { - enum { OP_REG, OP_MEM, OP_IMM, OP_XMM, OP_NONE } type; + enum { OP_REG, OP_MEM, OP_IMM, OP_XMM, OP_MM, OP_NONE } type; unsigned int bytes; union { unsigned long orig_val; @@ -213,12 +213,14 @@ struct operand { unsigned seg; } mem; unsigned xmm; + unsigned mm; } addr; union { unsigned long val; u64 val64; char valptr[sizeof(unsigned long) + 2]; sse128_t vec_val; + u64 mm_val; }; }; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index fb39e0b..0011b4a 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -142,6 +142,7 @@ #define Src2FS (OpFS << Src2Shift) #define Src2GS (OpGS << Src2Shift) #define Src2Mask (OpMask << Src2Shift) +#define Mmx ((u64)1 << 40) /* MMX Vector instruction */ #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 */ @@ -887,6 +888,40 @@ static void write_sse_reg(struct x86_emulate_ctxt *ctxt, sse128_t *data, ctxt->ops->put_fpu(ctxt); } +static void read_mmx_reg(struct x86_emulate_ctxt *ctxt, u64 *data, int reg) +{ + ctxt->ops->get_fpu(ctxt); + switch (reg) { + case 0: asm("movq %%mm0, %0" : "=m"(*data)); break; + case 1: asm("movq %%mm1, %0" : "=m"(*data)); break; + case 2: asm("movq %%mm2, %0" : "=m"(*data)); break; + case 3: asm("movq %%mm3, %0" : "=m"(*data)); break; + case 4: asm("movq %%mm4, %0" : "=m"(*data)); break; + case 5: asm("movq %%mm5, %0" : "=m"(*data)); break; + case 6: asm("movq %%mm6, %0" : "=m"(*data)); break; + case 7: asm("movq %%mm7, %0" : "=m"(*data)); break; + default: BUG(); + } + ctxt->ops->put_fpu(ctxt); +} + +static void write_mmx_reg(struct x86_emulate_ctxt *ctxt, u64 *data, int reg) +{ + ctxt->ops->get_fpu(ctxt); + switch (reg) { + case 0: asm("movq %0, %%mm0" : : "m"(*data)); break; + case 1: asm("movq %0, %%mm1" : : "m"(*data)); break; + case 2: asm("movq %0, %%mm2" : : "m"(*data)); break; + case 3: asm("movq %0, %%mm3" : : "m"(*data)); break; + case 4: asm("movq %0, %%mm4" : : "m"(*data)); break; + case 5: asm("movq %0, %%mm5" : : "m"(*data)); break; + case 6: asm("movq %0, %%mm6" : : "m"(*data)); break; + case 7: asm("movq %0, %%mm7" : : "m"(*data)); break; + default: BUG(); + } + ctxt->ops->put_fpu(ctxt); +} + static void decode_register_operand(struct x86_emulate_ctxt *ctxt, struct operand *op) { @@ -903,6 +938,13 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt, read_sse_reg(ctxt, &op->vec_val, reg); return; } + if (ctxt->d & Mmx) { + reg &= 7; + op->type = OP_MM; + op->bytes = 8; + op->addr.mm = reg; + return; + } op->type = OP_REG; if (ctxt->d & ByteOp) { @@ -948,6 +990,12 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, read_sse_reg(ctxt, &op->vec_val, ctxt->modrm_rm); return rc; } + if (ctxt->d & Mmx) { + op->type = OP_MM; + op->bytes = 8; + op->addr.xmm = ctxt->modrm_rm & 7; + return rc; + } fetch_register_operand(op); return rc; } @@ -1415,6 +1463,9 @@ static int writeback(struct x86_emulate_ctxt *ctxt) case OP_XMM: write_sse_reg(ctxt, &ctxt->dst.vec_val, ctxt->dst.addr.xmm); break; + case OP_MM: + write_mmx_reg(ctxt, &ctxt->dst.mm_val, ctxt->dst.addr.mm); + break; case OP_NONE: /* no writeback */ break; @@ -3987,6 +4038,8 @@ done_prefixes: if (ctxt->d & Sse) ctxt->op_bytes = 16; + else if (ctxt->d & Mmx) + ctxt->op_bytes = 8; /* ModRM and SIB bytes. */ if (ctxt->d & ModRM) { @@ -4057,6 +4110,35 @@ static bool string_insn_completed(struct x86_emulate_ctxt *ctxt) return false; } +static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt) +{ + bool fault = false; + + ctxt->ops->get_fpu(ctxt); + asm volatile("1: fwait \n\t" + "2: \n\t" + ".pushsection .fixup,\"ax\" \n\t" + "3: \n\t" + "movb $1, %[fault] \n\t" + "jmp 2b \n\t" + ".popsection \n\t" + _ASM_EXTABLE(1b, 3b) + : [fault]"+rm"(fault)); + ctxt->ops->put_fpu(ctxt); + + if (unlikely(fault)) + return emulate_exception(ctxt, MF_VECTOR, 0, false); + + return X86EMUL_CONTINUE; +} + +static void fetch_possible_mmx_operand(struct x86_emulate_ctxt *ctxt, + struct operand *op) +{ + if (op->type == OP_MM) + read_mmx_reg(ctxt, &op->mm_val, op->addr.mm); +} + int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) { struct x86_emulate_ops *ops = ctxt->ops; @@ -4081,18 +4163,31 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) goto done; } - if ((ctxt->d & Sse) - && ((ops->get_cr(ctxt, 0) & X86_CR0_EM) - || !(ops->get_cr(ctxt, 4) & X86_CR4_OSFXSR))) { + if (((ctxt->d & (Sse|Mmx)) && ((ops->get_cr(ctxt, 0) & X86_CR0_EM))) + || ((ctxt->d & Sse) && !(ops->get_cr(ctxt, 4) & X86_CR4_OSFXSR))) { rc = emulate_ud(ctxt); goto done; } - if ((ctxt->d & Sse) && (ops->get_cr(ctxt, 0) & X86_CR0_TS)) { + if ((ctxt->d & (Sse|Mmx)) && (ops->get_cr(ctxt, 0) & X86_CR0_TS)) { rc = emulate_nm(ctxt); goto done; } + if (ctxt->d & Mmx) { + rc = flush_pending_x87_faults(ctxt); + if (rc != X86EMUL_CONTINUE) + goto done; + /* + * Now that we know the fpu is exception safe, we can fetch + * operands from it. + */ + fetch_possible_mmx_operand(ctxt, &ctxt->src); + fetch_possible_mmx_operand(ctxt, &ctxt->src2); + if (!(ctxt->d & Mov)) + fetch_possible_mmx_operand(ctxt, &ctxt->dst); + } + if (unlikely(ctxt->guest_mode) && ctxt->intercept) { rc = emulator_check_intercept(ctxt, ctxt->intercept, X86_ICPT_PRE_EXCEPT); -- 2.7.4