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https://github.com/torvalds/linux.git
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KVM: Cleanup string I/O instruction emulation
Both vmx and svm decode the I/O instructions, and both botch the job, requiring the instruction prefixes to be fetched in order to completely decode the instruction. So, if we see a string I/O instruction, use the x86 emulator to decode it, as it already has all the prefix decoding machinery. This patch defines ins/outs opcodes in x86_emulate.c and calls emulate_instruction() from io_interception() (svm.c) and from handle_io() (vmx.c). It removes all vmx/svm prefix instruction decoders (get_addr_size(), io_get_override(), io_address(), get_io_count()) Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net> Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Laurent Vivier
Avi Kivity
parent
9fdaaac38e
commit
e70669abd4
@ -1221,7 +1221,10 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
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emulate_ctxt.fs_base = get_segment_base(vcpu, VCPU_SREG_FS);
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vcpu->mmio_is_write = 0;
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vcpu->pio.string = 0;
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r = x86_emulate_memop(&emulate_ctxt, &emulate_ops);
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if (vcpu->pio.string)
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return EMULATE_DO_MMIO;
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if ((r || vcpu->mmio_is_write) && run) {
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run->exit_reason = KVM_EXIT_MMIO;
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@ -98,20 +98,6 @@ static inline u32 svm_has(u32 feat)
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return svm_features & feat;
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}
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static unsigned get_addr_size(struct vcpu_svm *svm)
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{
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struct vmcb_save_area *sa = &svm->vmcb->save;
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u16 cs_attrib;
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if (!(sa->cr0 & X86_CR0_PE) || (sa->rflags & X86_EFLAGS_VM))
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return 2;
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cs_attrib = sa->cs.attrib;
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return (cs_attrib & SVM_SELECTOR_L_MASK) ? 8 :
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(cs_attrib & SVM_SELECTOR_DB_MASK) ? 4 : 2;
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}
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static inline u8 pop_irq(struct kvm_vcpu *vcpu)
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{
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int word_index = __ffs(vcpu->irq_summary);
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@ -995,147 +981,32 @@ static int shutdown_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
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return 0;
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}
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static int io_get_override(struct vcpu_svm *svm,
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struct vmcb_seg **seg,
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int *addr_override)
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{
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u8 inst[MAX_INST_SIZE];
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unsigned ins_length;
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gva_t rip;
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int i;
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rip = svm->vmcb->save.rip;
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ins_length = svm->next_rip - rip;
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rip += svm->vmcb->save.cs.base;
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if (ins_length > MAX_INST_SIZE)
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printk(KERN_DEBUG
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"%s: inst length err, cs base 0x%llx rip 0x%llx "
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"next rip 0x%llx ins_length %u\n",
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__FUNCTION__,
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svm->vmcb->save.cs.base,
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svm->vmcb->save.rip,
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svm->vmcb->control.exit_info_2,
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ins_length);
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if (emulator_read_std(rip, inst, ins_length, &svm->vcpu)
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!= X86EMUL_CONTINUE)
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/* #PF */
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return 0;
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*addr_override = 0;
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*seg = NULL;
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for (i = 0; i < ins_length; i++)
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switch (inst[i]) {
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case 0xf0:
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case 0xf2:
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case 0xf3:
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case 0x66:
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continue;
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case 0x67:
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*addr_override = 1;
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continue;
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case 0x2e:
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*seg = &svm->vmcb->save.cs;
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continue;
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case 0x36:
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*seg = &svm->vmcb->save.ss;
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continue;
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case 0x3e:
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*seg = &svm->vmcb->save.ds;
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continue;
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case 0x26:
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*seg = &svm->vmcb->save.es;
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continue;
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case 0x64:
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*seg = &svm->vmcb->save.fs;
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continue;
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case 0x65:
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*seg = &svm->vmcb->save.gs;
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continue;
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default:
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return 1;
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}
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printk(KERN_DEBUG "%s: unexpected\n", __FUNCTION__);
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return 0;
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}
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static unsigned long io_address(struct vcpu_svm *svm, int ins, gva_t *address)
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{
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unsigned long addr_mask;
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unsigned long *reg;
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struct vmcb_seg *seg;
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int addr_override;
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struct vmcb_save_area *save_area = &svm->vmcb->save;
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u16 cs_attrib = save_area->cs.attrib;
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unsigned addr_size = get_addr_size(svm);
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if (!io_get_override(svm, &seg, &addr_override))
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return 0;
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if (addr_override)
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addr_size = (addr_size == 2) ? 4: (addr_size >> 1);
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if (ins) {
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reg = &svm->vcpu.regs[VCPU_REGS_RDI];
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seg = &svm->vmcb->save.es;
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} else {
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reg = &svm->vcpu.regs[VCPU_REGS_RSI];
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seg = (seg) ? seg : &svm->vmcb->save.ds;
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}
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addr_mask = ~0ULL >> (64 - (addr_size * 8));
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if ((cs_attrib & SVM_SELECTOR_L_MASK) &&
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!(svm->vmcb->save.rflags & X86_EFLAGS_VM)) {
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*address = (*reg & addr_mask);
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return addr_mask;
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}
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if (!(seg->attrib & SVM_SELECTOR_P_SHIFT)) {
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svm_inject_gp(&svm->vcpu, 0);
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return 0;
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}
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*address = (*reg & addr_mask) + seg->base;
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return addr_mask;
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}
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static int io_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
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{
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u32 io_info = svm->vmcb->control.exit_info_1; //address size bug?
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int size, down, in, string, rep;
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unsigned port;
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unsigned long count;
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gva_t address = 0;
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++svm->vcpu.stat.io_exits;
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svm->next_rip = svm->vmcb->control.exit_info_2;
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string = (io_info & SVM_IOIO_STR_MASK) != 0;
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if (string) {
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if (emulate_instruction(&svm->vcpu, kvm_run, 0, 0) == EMULATE_DO_MMIO)
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return 0;
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return 1;
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}
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in = (io_info & SVM_IOIO_TYPE_MASK) != 0;
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port = io_info >> 16;
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size = (io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT;
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string = (io_info & SVM_IOIO_STR_MASK) != 0;
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rep = (io_info & SVM_IOIO_REP_MASK) != 0;
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count = 1;
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down = (svm->vmcb->save.rflags & X86_EFLAGS_DF) != 0;
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if (string) {
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unsigned addr_mask;
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addr_mask = io_address(svm, in, &address);
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if (!addr_mask) {
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printk(KERN_DEBUG "%s: get io address failed\n",
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__FUNCTION__);
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return 1;
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}
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if (rep)
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count = svm->vcpu.regs[VCPU_REGS_RCX] & addr_mask;
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}
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return kvm_setup_pio(&svm->vcpu, kvm_run, in, size, count, string,
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down, address, rep, port);
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return kvm_setup_pio(&svm->vcpu, kvm_run, in, size, 1, 0,
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down, 0, rep, port);
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}
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static int nop_on_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
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@ -1763,82 +1763,30 @@ static int handle_triple_fault(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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return 0;
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}
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static int get_io_count(struct kvm_vcpu *vcpu, unsigned long *count)
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{
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u64 inst;
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gva_t rip;
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int countr_size;
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int i;
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if ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_VM)) {
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countr_size = 2;
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} else {
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u32 cs_ar = vmcs_read32(GUEST_CS_AR_BYTES);
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countr_size = (cs_ar & AR_L_MASK) ? 8:
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(cs_ar & AR_DB_MASK) ? 4: 2;
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}
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rip = vmcs_readl(GUEST_RIP);
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if (countr_size != 8)
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rip += vmcs_readl(GUEST_CS_BASE);
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if (emulator_read_std(rip, &inst, sizeof(inst), vcpu) !=
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X86EMUL_CONTINUE)
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return 0;
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for (i = 0; i < sizeof(inst); i++) {
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switch (((u8*)&inst)[i]) {
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case 0xf0:
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case 0xf2:
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case 0xf3:
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case 0x2e:
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case 0x36:
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case 0x3e:
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case 0x26:
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case 0x64:
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case 0x65:
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case 0x66:
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break;
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case 0x67:
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countr_size = (countr_size == 2) ? 4: (countr_size >> 1);
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default:
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goto done;
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}
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}
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return 0;
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done:
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countr_size *= 8;
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*count = vcpu->regs[VCPU_REGS_RCX] & (~0ULL >> (64 - countr_size));
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//printk("cx: %lx\n", vcpu->regs[VCPU_REGS_RCX]);
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return 1;
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}
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static int handle_io(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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{
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u64 exit_qualification;
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int size, down, in, string, rep;
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unsigned port;
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unsigned long count;
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gva_t address;
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++vcpu->stat.io_exits;
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exit_qualification = vmcs_read64(EXIT_QUALIFICATION);
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in = (exit_qualification & 8) != 0;
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size = (exit_qualification & 7) + 1;
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string = (exit_qualification & 16) != 0;
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if (string) {
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if (emulate_instruction(vcpu, kvm_run, 0, 0) == EMULATE_DO_MMIO)
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return 0;
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return 1;
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}
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size = (exit_qualification & 7) + 1;
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in = (exit_qualification & 8) != 0;
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down = (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_DF) != 0;
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count = 1;
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rep = (exit_qualification & 32) != 0;
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port = exit_qualification >> 16;
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address = 0;
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if (string) {
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if (rep && !get_io_count(vcpu, &count))
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return 1;
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address = vmcs_readl(GUEST_LINEAR_ADDRESS);
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}
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return kvm_setup_pio(vcpu, kvm_run, in, size, count, string, down,
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address, rep, port);
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return kvm_setup_pio(vcpu, kvm_run, in, size, 1, 0, down,
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0, rep, port);
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}
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static void
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@ -103,9 +103,12 @@ static u8 opcode_table[256] = {
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/* 0x58 - 0x5F */
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ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
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ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
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/* 0x60 - 0x6F */
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/* 0x60 - 0x6B */
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0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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/* 0x6C - 0x6F */
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SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps, /* insb, insw/insd */
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SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps, /* outsb, outsw/outsd */
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/* 0x70 - 0x7F */
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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/* 0x80 - 0x87 */
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@ -428,10 +431,11 @@ struct operand {
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})
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/* Access/update address held in a register, based on addressing mode. */
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#define address_mask(reg) \
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((ad_bytes == sizeof(unsigned long)) ? \
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(reg) : ((reg) & ((1UL << (ad_bytes << 3)) - 1)))
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#define register_address(base, reg) \
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((base) + ((ad_bytes == sizeof(unsigned long)) ? (reg) : \
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((reg) & ((1UL << (ad_bytes << 3)) - 1))))
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((base) + address_mask(reg))
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#define register_address_increment(reg, inc) \
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do { \
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/* signed type ensures sign extension to long */ \
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@ -1116,6 +1120,41 @@ done:
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special_insn:
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if (twobyte)
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goto twobyte_special_insn;
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switch(b) {
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case 0x6c: /* insb */
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case 0x6d: /* insw/insd */
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if (kvm_setup_pio(ctxt->vcpu, NULL,
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1, /* in */
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(d & ByteOp) ? 1 : op_bytes, /* size */
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rep_prefix ?
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address_mask(_regs[VCPU_REGS_RCX]) : 1, /* count */
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1, /* strings */
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(_eflags & EFLG_DF), /* down */
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register_address(ctxt->es_base,
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_regs[VCPU_REGS_RDI]), /* address */
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rep_prefix,
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_regs[VCPU_REGS_RDX] /* port */
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) == 0)
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return -1;
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return 0;
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case 0x6e: /* outsb */
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case 0x6f: /* outsw/outsd */
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if (kvm_setup_pio(ctxt->vcpu, NULL,
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0, /* in */
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(d & ByteOp) ? 1 : op_bytes, /* size */
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rep_prefix ?
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address_mask(_regs[VCPU_REGS_RCX]) : 1, /* count */
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1, /* strings */
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(_eflags & EFLG_DF), /* down */
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register_address(override_base ?
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*override_base : ctxt->ds_base,
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_regs[VCPU_REGS_RSI]), /* address */
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rep_prefix,
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_regs[VCPU_REGS_RDX] /* port */
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) == 0)
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return -1;
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return 0;
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}
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if (rep_prefix) {
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if (_regs[VCPU_REGS_RCX] == 0) {
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ctxt->vcpu->rip = _eip;
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