Avi Kivity wrote: > Laurent Vivier wrote: >>> >>> How about just calliing emulate_instruction() from here (just for the >>> string case)? That will eliminate all the setup code. >>> >> >> But this setup is in emulate_instruction() so it will be executed anyway. >> >> > > I'm not worried about run-time overhead, but about the amount of code. > >>> x86_emulate_memop() will need to be extended to decode ins/outs, but >>> that's fairly easy. >>> >> >> X86_decode_prefix() is a subset of instruction decoding part of >> x86_emulate_memop(), kvm_setup_pio() can be seen as a subset of >> instruction >> emulating part of x86_emulate_memop(). So I think in term of >> performance it is >> better to do like that, but I agree by doing: >> >> if (string) >> return emulate_instruction(vcpu, kvm_run, 0, 0); >> else >> return kvm_setup_pio(vcpu, kvm_run, in, size, port); >> >> it is more more ... more simple. >> >> If you prefer simplicity, I can do like that ? >> (but I know you prefer simplicity...) >> >> > > Yes. Note that x86_emulate_memop() will eventually call kvm_setup_pio() > to complete the emulation.
Just to have some comments, have a look to my little dirty patch (see attachment) Laurent -- ------------- [EMAIL PROTECTED] -------------- "Software is hard" - Donald Knuth
Index: kvm/drivers/kvm/kvm_main.c =================================================================== --- kvm.orig/drivers/kvm/kvm_main.c 2007-08-02 18:32:19.000000000 +0200 +++ kvm/drivers/kvm/kvm_main.c 2007-08-02 18:32:22.000000000 +0200 @@ -1222,6 +1222,8 @@ vcpu->mmio_is_write = 0; r = x86_emulate_memop(&emulate_ctxt, &emulate_ops); + if (vcpu->pio.count) + return EMULATE_DO_MMIO; if ((r || vcpu->mmio_is_write) && run) { run->exit_reason = KVM_EXIT_MMIO; Index: kvm/drivers/kvm/svm.c =================================================================== --- kvm.orig/drivers/kvm/svm.c 2007-08-02 18:32:19.000000000 +0200 +++ kvm/drivers/kvm/svm.c 2007-08-02 18:35:03.000000000 +0200 @@ -98,20 +98,6 @@ return svm_features & feat; } -static unsigned get_addr_size(struct vcpu_svm *svm) -{ - struct vmcb_save_area *sa = &svm->vmcb->save; - u16 cs_attrib; - - if (!(sa->cr0 & X86_CR0_PE) || (sa->rflags & X86_EFLAGS_VM)) - return 2; - - cs_attrib = sa->cs.attrib; - - return (cs_attrib & SVM_SELECTOR_L_MASK) ? 8 : - (cs_attrib & SVM_SELECTOR_DB_MASK) ? 4 : 2; -} - static inline u8 pop_irq(struct kvm_vcpu *vcpu) { int word_index = __ffs(vcpu->irq_summary); @@ -995,147 +981,32 @@ return 0; } -static int io_get_override(struct vcpu_svm *svm, - struct vmcb_seg **seg, - int *addr_override) -{ - u8 inst[MAX_INST_SIZE]; - unsigned ins_length; - gva_t rip; - int i; - - rip = svm->vmcb->save.rip; - ins_length = svm->next_rip - rip; - rip += svm->vmcb->save.cs.base; - - if (ins_length > MAX_INST_SIZE) - printk(KERN_DEBUG - "%s: inst length err, cs base 0x%llx rip 0x%llx " - "next rip 0x%llx ins_length %u\n", - __FUNCTION__, - svm->vmcb->save.cs.base, - svm->vmcb->save.rip, - svm->vmcb->control.exit_info_2, - ins_length); - - if (emulator_read_std(rip, inst, ins_length, &svm->vcpu) - != X86EMUL_CONTINUE) - /* #PF */ - return 0; - - *addr_override = 0; - *seg = NULL; - for (i = 0; i < ins_length; i++) - switch (inst[i]) { - case 0xf0: - case 0xf2: - case 0xf3: - case 0x66: - continue; - case 0x67: - *addr_override = 1; - continue; - case 0x2e: - *seg = &svm->vmcb->save.cs; - continue; - case 0x36: - *seg = &svm->vmcb->save.ss; - continue; - case 0x3e: - *seg = &svm->vmcb->save.ds; - continue; - case 0x26: - *seg = &svm->vmcb->save.es; - continue; - case 0x64: - *seg = &svm->vmcb->save.fs; - continue; - case 0x65: - *seg = &svm->vmcb->save.gs; - continue; - default: - return 1; - } - printk(KERN_DEBUG "%s: unexpected\n", __FUNCTION__); - return 0; -} - -static unsigned long io_address(struct vcpu_svm *svm, int ins, gva_t *address) -{ - unsigned long addr_mask; - unsigned long *reg; - struct vmcb_seg *seg; - int addr_override; - struct vmcb_save_area *save_area = &svm->vmcb->save; - u16 cs_attrib = save_area->cs.attrib; - unsigned addr_size = get_addr_size(svm); - - if (!io_get_override(svm, &seg, &addr_override)) - return 0; - - if (addr_override) - addr_size = (addr_size == 2) ? 4: (addr_size >> 1); - - if (ins) { - reg = &svm->vcpu.regs[VCPU_REGS_RDI]; - seg = &svm->vmcb->save.es; - } else { - reg = &svm->vcpu.regs[VCPU_REGS_RSI]; - seg = (seg) ? seg : &svm->vmcb->save.ds; - } - - addr_mask = ~0ULL >> (64 - (addr_size * 8)); - - if ((cs_attrib & SVM_SELECTOR_L_MASK) && - !(svm->vmcb->save.rflags & X86_EFLAGS_VM)) { - *address = (*reg & addr_mask); - return addr_mask; - } - - if (!(seg->attrib & SVM_SELECTOR_P_SHIFT)) { - svm_inject_gp(&svm->vcpu, 0); - return 0; - } - - *address = (*reg & addr_mask) + seg->base; - return addr_mask; -} - static int io_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) { u32 io_info = svm->vmcb->control.exit_info_1; //address size bug? int size, down, in, string, rep; unsigned port; - unsigned long count; - gva_t address = 0; ++svm->vcpu.stat.io_exits; svm->next_rip = svm->vmcb->control.exit_info_2; + string = (io_info & SVM_IOIO_STR_MASK) != 0; + + if (string) { + if (emulate_instruction(&svm->vcpu, kvm_run, 0, 0) == EMULATE_DO_MMIO) + return 0; + return 1; + } + in = (io_info & SVM_IOIO_TYPE_MASK) != 0; port = io_info >> 16; size = (io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT; - string = (io_info & SVM_IOIO_STR_MASK) != 0; rep = (io_info & SVM_IOIO_REP_MASK) != 0; - count = 1; down = (svm->vmcb->save.rflags & X86_EFLAGS_DF) != 0; - if (string) { - unsigned addr_mask; - - addr_mask = io_address(svm, in, &address); - if (!addr_mask) { - printk(KERN_DEBUG "%s: get io address failed\n", - __FUNCTION__); - return 1; - } - - if (rep) - count = svm->vcpu.regs[VCPU_REGS_RCX] & addr_mask; - } - return kvm_setup_pio(&svm->vcpu, kvm_run, in, size, count, string, - down, address, rep, port); + return kvm_setup_pio(&svm->vcpu, kvm_run, in, size, 1, 0, + down, 0, rep, port); } static int nop_on_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) Index: kvm/drivers/kvm/vmx.c =================================================================== --- kvm.orig/drivers/kvm/vmx.c 2007-08-02 18:32:19.000000000 +0200 +++ kvm/drivers/kvm/vmx.c 2007-08-02 18:34:39.000000000 +0200 @@ -1761,82 +1761,30 @@ return 0; } -static int get_io_count(struct kvm_vcpu *vcpu, unsigned long *count) -{ - u64 inst; - gva_t rip; - int countr_size; - int i; - - if ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_VM)) { - countr_size = 2; - } else { - u32 cs_ar = vmcs_read32(GUEST_CS_AR_BYTES); - - countr_size = (cs_ar & AR_L_MASK) ? 8: - (cs_ar & AR_DB_MASK) ? 4: 2; - } - - rip = vmcs_readl(GUEST_RIP); - if (countr_size != 8) - rip += vmcs_readl(GUEST_CS_BASE); - - if (emulator_read_std(rip, &inst, sizeof(inst), vcpu) != - X86EMUL_CONTINUE) - return 0; - - for (i = 0; i < sizeof(inst); i++) { - switch (((u8*)&inst)[i]) { - case 0xf0: - case 0xf2: - case 0xf3: - case 0x2e: - case 0x36: - case 0x3e: - case 0x26: - case 0x64: - case 0x65: - case 0x66: - break; - case 0x67: - countr_size = (countr_size == 2) ? 4: (countr_size >> 1); - default: - goto done; - } - } - return 0; -done: - countr_size *= 8; - *count = vcpu->regs[VCPU_REGS_RCX] & (~0ULL >> (64 - countr_size)); - //printk("cx: %lx\n", vcpu->regs[VCPU_REGS_RCX]); - return 1; -} - static int handle_io(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) { u64 exit_qualification; int size, down, in, string, rep; unsigned port; - unsigned long count; - gva_t address; ++vcpu->stat.io_exits; exit_qualification = vmcs_read64(EXIT_QUALIFICATION); - in = (exit_qualification & 8) != 0; - size = (exit_qualification & 7) + 1; string = (exit_qualification & 16) != 0; + + if (string) { + if (emulate_instruction(vcpu, kvm_run, 0, 0) == EMULATE_DO_MMIO) + return 0; + return 1; + } + + size = (exit_qualification & 7) + 1; + in = (exit_qualification & 8) != 0; down = (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_DF) != 0; - count = 1; rep = (exit_qualification & 32) != 0; port = exit_qualification >> 16; - address = 0; - if (string) { - if (rep && !get_io_count(vcpu, &count)) - return 1; - address = vmcs_readl(GUEST_LINEAR_ADDRESS); - } - return kvm_setup_pio(vcpu, kvm_run, in, size, count, string, down, - address, rep, port); + + return kvm_setup_pio(vcpu, kvm_run, in, size, 1, 0, down, + 0, rep, port); } static void Index: kvm/drivers/kvm/x86_emulate.c =================================================================== --- kvm.orig/drivers/kvm/x86_emulate.c 2007-08-02 18:32:19.000000000 +0200 +++ kvm/drivers/kvm/x86_emulate.c 2007-08-02 18:34:06.000000000 +0200 @@ -103,9 +103,12 @@ /* 0x58 - 0x5F */ ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps, - /* 0x60 - 0x6F */ + /* 0x60 - 0x6B */ 0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ , - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + /* 0x6C - 0x6F */ + ByteOp | ImplicitOps, ImplicitOps, /* insb, insw/insd */ + ByteOp | ImplicitOps, ImplicitOps, /* outsb, outsw/outsd */ /* 0x70 - 0x7F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x80 - 0x87 */ @@ -428,10 +431,11 @@ }) /* Access/update address held in a register, based on addressing mode. */ +#define address_mask(reg) \ + ((ad_bytes == sizeof(unsigned long)) ? \ + (reg) : ((reg) & ((1UL << (ad_bytes << 3)) - 1))) #define register_address(base, reg) \ - ((base) + ((ad_bytes == sizeof(unsigned long)) ? (reg) : \ - ((reg) & ((1UL << (ad_bytes << 3)) - 1)))) - + ((base) + address_mask(reg)) #define register_address_increment(reg, inc) \ do { \ /* signed type ensures sign extension to long */ \ @@ -1139,6 +1143,39 @@ register_address_increment(_regs[VCPU_REGS_RDI], (_eflags & EFLG_DF) ? -dst.bytes : dst.bytes); break; + case 0x6c: /* insb */ + case 0x6d: /* insw/insd */ + if (kvm_setup_pio(ctxt->vcpu, NULL, + 1, /* in */ + (d & ByteOp) ? 1 : op_bytes, /* size */ + rep_prefix ? + address_mask(_regs[VCPU_REGS_RCX]) + 1: 1, /* count */ + 1, /* strings */ + (_eflags & EFLG_DF), /* down */ + register_address(ctxt->es_base, + _regs[VCPU_REGS_RDI]), /* address */ + rep_prefix, + _regs[VCPU_REGS_RDX] /* port */ + ) == 0) + return -1; + return 0; + case 0x6e: /* outsb */ + case 0x6f: /* outsw/outsd */ + if (kvm_setup_pio(ctxt->vcpu, NULL, + 0, /* in */ + (d & ByteOp) ? 1 : op_bytes, /* size */ + rep_prefix ? + address_mask(_regs[VCPU_REGS_RCX]) + 1: 1, /* count */ + 1, /* strings */ + (_eflags & EFLG_DF), /* down */ + register_address(override_base ? + *override_base : ctxt->ds_base, + _regs[VCPU_REGS_RSI]), /* address */ + rep_prefix, + _regs[VCPU_REGS_RDX] /* port */ + ) == 0) + return -1; + return 0; case 0xa6 ... 0xa7: /* cmps */ DPRINTF("Urk! I don't handle CMPS.\n"); goto cannot_emulate;
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