KVM: Call x86_decode_insn() only when needed
Move emulate_ctxt to kvm_vcpu to keep emulate context when we exit from kvm module. Call x86_decode_insn() only when needed. Modify x86_emulate_insn() to not modify the context if it must be re-entered. Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net> Signed-off-by: Avi Kivity <avi@qumranet.com>
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@ -207,6 +207,8 @@ enum {
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VCPU_SREG_LDTR,
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};
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#include "x86_emulate.h"
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struct kvm_pio_request {
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unsigned long count;
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int cur_count;
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@ -380,6 +382,10 @@ struct kvm_vcpu {
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int cpuid_nent;
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struct kvm_cpuid_entry cpuid_entries[KVM_MAX_CPUID_ENTRIES];
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/* emulate context */
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struct x86_emulate_ctxt emulate_ctxt;
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};
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struct kvm_mem_alias {
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@ -555,7 +561,7 @@ enum emulation_result {
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};
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int emulate_instruction(struct kvm_vcpu *vcpu, struct kvm_run *run,
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unsigned long cr2, u16 error_code);
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unsigned long cr2, u16 error_code, int no_decode);
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void kvm_report_emulation_failure(struct kvm_vcpu *cvpu, const char *context);
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void realmode_lgdt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);
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void realmode_lidt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);
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@ -1251,45 +1251,56 @@ struct x86_emulate_ops emulate_ops = {
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int emulate_instruction(struct kvm_vcpu *vcpu,
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struct kvm_run *run,
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unsigned long cr2,
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u16 error_code)
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u16 error_code,
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int no_decode)
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{
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struct x86_emulate_ctxt emulate_ctxt;
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int r;
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int cs_db, cs_l;
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int r = 0;
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vcpu->mmio_fault_cr2 = cr2;
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kvm_x86_ops->cache_regs(vcpu);
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kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
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emulate_ctxt.vcpu = vcpu;
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emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
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emulate_ctxt.cr2 = cr2;
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emulate_ctxt.mode = (emulate_ctxt.eflags & X86_EFLAGS_VM)
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? X86EMUL_MODE_REAL : cs_l
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? X86EMUL_MODE_PROT64 : cs_db
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? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
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if (emulate_ctxt.mode == X86EMUL_MODE_PROT64) {
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emulate_ctxt.cs_base = 0;
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emulate_ctxt.ds_base = 0;
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emulate_ctxt.es_base = 0;
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emulate_ctxt.ss_base = 0;
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} else {
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emulate_ctxt.cs_base = get_segment_base(vcpu, VCPU_SREG_CS);
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emulate_ctxt.ds_base = get_segment_base(vcpu, VCPU_SREG_DS);
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emulate_ctxt.es_base = get_segment_base(vcpu, VCPU_SREG_ES);
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emulate_ctxt.ss_base = get_segment_base(vcpu, VCPU_SREG_SS);
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}
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emulate_ctxt.gs_base = get_segment_base(vcpu, VCPU_SREG_GS);
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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_decode_insn(&emulate_ctxt, &emulate_ops);
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if (!no_decode) {
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int cs_db, cs_l;
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kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
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vcpu->emulate_ctxt.vcpu = vcpu;
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vcpu->emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
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vcpu->emulate_ctxt.cr2 = cr2;
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vcpu->emulate_ctxt.mode =
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(vcpu->emulate_ctxt.eflags & X86_EFLAGS_VM)
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? X86EMUL_MODE_REAL : cs_l
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? X86EMUL_MODE_PROT64 : cs_db
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? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
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if (vcpu->emulate_ctxt.mode == X86EMUL_MODE_PROT64) {
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vcpu->emulate_ctxt.cs_base = 0;
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vcpu->emulate_ctxt.ds_base = 0;
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vcpu->emulate_ctxt.es_base = 0;
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vcpu->emulate_ctxt.ss_base = 0;
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} else {
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vcpu->emulate_ctxt.cs_base =
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get_segment_base(vcpu, VCPU_SREG_CS);
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vcpu->emulate_ctxt.ds_base =
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get_segment_base(vcpu, VCPU_SREG_DS);
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vcpu->emulate_ctxt.es_base =
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get_segment_base(vcpu, VCPU_SREG_ES);
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vcpu->emulate_ctxt.ss_base =
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get_segment_base(vcpu, VCPU_SREG_SS);
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}
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vcpu->emulate_ctxt.gs_base =
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get_segment_base(vcpu, VCPU_SREG_GS);
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vcpu->emulate_ctxt.fs_base =
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get_segment_base(vcpu, VCPU_SREG_FS);
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r = x86_decode_insn(&vcpu->emulate_ctxt, &emulate_ops);
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}
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if (r == 0)
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r = x86_emulate_insn(&emulate_ctxt, &emulate_ops);
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r = x86_emulate_insn(&vcpu->emulate_ctxt, &emulate_ops);
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if (vcpu->pio.string)
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return EMULATE_DO_MMIO;
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@ -1313,7 +1324,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
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}
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kvm_x86_ops->decache_regs(vcpu);
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kvm_x86_ops->set_rflags(vcpu, emulate_ctxt.eflags);
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kvm_x86_ops->set_rflags(vcpu, vcpu->emulate_ctxt.eflags);
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if (vcpu->mmio_is_write) {
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vcpu->mmio_needed = 0;
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@ -2055,7 +2066,7 @@ static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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vcpu->mmio_read_completed = 1;
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vcpu->mmio_needed = 0;
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r = emulate_instruction(vcpu, kvm_run,
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vcpu->mmio_fault_cr2, 0);
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vcpu->mmio_fault_cr2, 0, 1);
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if (r == EMULATE_DO_MMIO) {
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/*
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* Read-modify-write. Back to userspace.
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@ -960,7 +960,7 @@ static int pf_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
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return 1;
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}
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er = emulate_instruction(&svm->vcpu, kvm_run, fault_address,
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error_code);
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error_code, 0);
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mutex_unlock(&kvm->lock);
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switch (er) {
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@ -984,7 +984,7 @@ static int ud_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
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{
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int er;
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er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0);
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er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0, 0);
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if (er != EMULATE_DONE)
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inject_ud(&svm->vcpu);
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@ -1027,7 +1027,8 @@ static int io_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
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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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if (emulate_instruction(&svm->vcpu,
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kvm_run, 0, 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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@ -1086,7 +1087,7 @@ static int cpuid_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
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static int emulate_on_interception(struct vcpu_svm *svm,
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struct kvm_run *kvm_run)
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{
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if (emulate_instruction(&svm->vcpu, NULL, 0, 0) != EMULATE_DONE)
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if (emulate_instruction(&svm->vcpu, NULL, 0, 0, 0) != EMULATE_DONE)
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pr_unimpl(&svm->vcpu, "%s: failed\n", __FUNCTION__);
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return 1;
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}
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@ -1750,7 +1750,7 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
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* Cause the #SS fault with 0 error code in VM86 mode.
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*/
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if (((vec == GP_VECTOR) || (vec == SS_VECTOR)) && err_code == 0)
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if (emulate_instruction(vcpu, NULL, 0, 0) == EMULATE_DONE)
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if (emulate_instruction(vcpu, NULL, 0, 0, 0) == EMULATE_DONE)
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return 1;
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return 0;
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}
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@ -1787,7 +1787,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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}
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if (is_invalid_opcode(intr_info)) {
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er = emulate_instruction(vcpu, kvm_run, 0, 0);
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er = emulate_instruction(vcpu, kvm_run, 0, 0, 0);
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if (er != EMULATE_DONE)
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vmx_inject_ud(vcpu);
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@ -1812,7 +1812,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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return 1;
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}
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er = emulate_instruction(vcpu, kvm_run, cr2, error_code);
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er = emulate_instruction(vcpu, kvm_run, cr2, error_code, 0);
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mutex_unlock(&vcpu->kvm->lock);
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switch (er) {
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@ -1873,7 +1873,8 @@ static int handle_io(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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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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if (emulate_instruction(vcpu,
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kvm_run, 0, 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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@ -913,10 +913,19 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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unsigned long cr2 = ctxt->cr2;
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int no_wb = 0;
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u64 msr_data;
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unsigned long saved_eip = 0;
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unsigned long _eflags = ctxt->eflags;
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struct decode_cache *c = &ctxt->decode;
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int rc = 0;
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/* Shadow copy of register state. Committed on successful emulation.
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* NOTE: we can copy them from vcpu as x86_decode_insn() doesn't
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* modify them.
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*/
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memcpy(c->regs, ctxt->vcpu->regs, sizeof c->regs);
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saved_eip = c->eip;
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if ((c->d & ModRM) && (c->modrm_mod != 3))
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cr2 = c->modrm_ea;
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@ -1250,7 +1259,11 @@ writeback:
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ctxt->vcpu->rip = c->eip;
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done:
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return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
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if (rc == X86EMUL_UNHANDLEABLE) {
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c->eip = saved_eip;
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return -1;
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}
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return 0;
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special_insn:
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if (c->twobyte)
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register_address(ctxt->es_base,
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c->regs[VCPU_REGS_RDI]),
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c->rep_prefix,
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c->regs[VCPU_REGS_RDX]) == 0)
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c->regs[VCPU_REGS_RDX]) == 0) {
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c->eip = saved_eip;
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return -1;
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}
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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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@ -1321,8 +1336,10 @@ push:
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ctxt->ds_base,
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c->regs[VCPU_REGS_RSI]),
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c->rep_prefix,
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c->regs[VCPU_REGS_RDX]) == 0)
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c->regs[VCPU_REGS_RDX]) == 0) {
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c->eip = saved_eip;
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return -1;
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}
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return 0;
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case 0x70 ... 0x7f: /* jcc (short) */ {
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int rel = insn_fetch(s8, 1, c->eip);
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@ -1711,5 +1728,6 @@ twobyte_special_insn:
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cannot_emulate:
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DPRINTF("Cannot emulate %02x\n", c->b);
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c->eip = saved_eip;
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return -1;
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}
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