From 3427318fd2244737a466a06a93c5fe579852f871 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Tue, 18 Sep 2007 11:27:37 +0200 Subject: [PATCH] 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 Signed-off-by: Avi Kivity --- drivers/kvm/kvm.h | 8 ++++- drivers/kvm/kvm_main.c | 77 +++++++++++++++++++++++++++-------------------- drivers/kvm/svm.c | 9 +++--- drivers/kvm/vmx.c | 9 +++--- drivers/kvm/x86_emulate.c | 24 +++++++++++++-- 5 files changed, 82 insertions(+), 45 deletions(-) diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h index da9c3aa..e885b19 100644 --- a/drivers/kvm/kvm.h +++ b/drivers/kvm/kvm.h @@ -207,6 +207,8 @@ enum { VCPU_SREG_LDTR, }; +#include "x86_emulate.h" + struct kvm_pio_request { unsigned long count; int cur_count; @@ -380,6 +382,10 @@ struct kvm_vcpu { int cpuid_nent; struct kvm_cpuid_entry cpuid_entries[KVM_MAX_CPUID_ENTRIES]; + + /* emulate context */ + + struct x86_emulate_ctxt emulate_ctxt; }; struct kvm_mem_alias { @@ -555,7 +561,7 @@ enum emulation_result { }; int emulate_instruction(struct kvm_vcpu *vcpu, struct kvm_run *run, - unsigned long cr2, u16 error_code); + unsigned long cr2, u16 error_code, int no_decode); void kvm_report_emulation_failure(struct kvm_vcpu *cvpu, const char *context); void realmode_lgdt(struct kvm_vcpu *vcpu, u16 size, unsigned long address); void realmode_lidt(struct kvm_vcpu *vcpu, u16 size, unsigned long address); diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index 800ab50..7104836 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -1251,45 +1251,56 @@ struct x86_emulate_ops emulate_ops = { int emulate_instruction(struct kvm_vcpu *vcpu, struct kvm_run *run, unsigned long cr2, - u16 error_code) + u16 error_code, + int no_decode) { - struct x86_emulate_ctxt emulate_ctxt; - int r; - int cs_db, cs_l; + int r = 0; vcpu->mmio_fault_cr2 = cr2; kvm_x86_ops->cache_regs(vcpu); - kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l); - - emulate_ctxt.vcpu = vcpu; - emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu); - emulate_ctxt.cr2 = cr2; - emulate_ctxt.mode = (emulate_ctxt.eflags & X86_EFLAGS_VM) - ? X86EMUL_MODE_REAL : cs_l - ? X86EMUL_MODE_PROT64 : cs_db - ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16; - - if (emulate_ctxt.mode == X86EMUL_MODE_PROT64) { - emulate_ctxt.cs_base = 0; - emulate_ctxt.ds_base = 0; - emulate_ctxt.es_base = 0; - emulate_ctxt.ss_base = 0; - } else { - emulate_ctxt.cs_base = get_segment_base(vcpu, VCPU_SREG_CS); - emulate_ctxt.ds_base = get_segment_base(vcpu, VCPU_SREG_DS); - emulate_ctxt.es_base = get_segment_base(vcpu, VCPU_SREG_ES); - emulate_ctxt.ss_base = get_segment_base(vcpu, VCPU_SREG_SS); - } - - emulate_ctxt.gs_base = get_segment_base(vcpu, VCPU_SREG_GS); - emulate_ctxt.fs_base = get_segment_base(vcpu, VCPU_SREG_FS); - vcpu->mmio_is_write = 0; vcpu->pio.string = 0; - r = x86_decode_insn(&emulate_ctxt, &emulate_ops); + + if (!no_decode) { + int cs_db, cs_l; + kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l); + + vcpu->emulate_ctxt.vcpu = vcpu; + vcpu->emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu); + vcpu->emulate_ctxt.cr2 = cr2; + vcpu->emulate_ctxt.mode = + (vcpu->emulate_ctxt.eflags & X86_EFLAGS_VM) + ? X86EMUL_MODE_REAL : cs_l + ? X86EMUL_MODE_PROT64 : cs_db + ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16; + + if (vcpu->emulate_ctxt.mode == X86EMUL_MODE_PROT64) { + vcpu->emulate_ctxt.cs_base = 0; + vcpu->emulate_ctxt.ds_base = 0; + vcpu->emulate_ctxt.es_base = 0; + vcpu->emulate_ctxt.ss_base = 0; + } else { + vcpu->emulate_ctxt.cs_base = + get_segment_base(vcpu, VCPU_SREG_CS); + vcpu->emulate_ctxt.ds_base = + get_segment_base(vcpu, VCPU_SREG_DS); + vcpu->emulate_ctxt.es_base = + get_segment_base(vcpu, VCPU_SREG_ES); + vcpu->emulate_ctxt.ss_base = + get_segment_base(vcpu, VCPU_SREG_SS); + } + + vcpu->emulate_ctxt.gs_base = + get_segment_base(vcpu, VCPU_SREG_GS); + vcpu->emulate_ctxt.fs_base = + get_segment_base(vcpu, VCPU_SREG_FS); + + r = x86_decode_insn(&vcpu->emulate_ctxt, &emulate_ops); + } + if (r == 0) - r = x86_emulate_insn(&emulate_ctxt, &emulate_ops); + r = x86_emulate_insn(&vcpu->emulate_ctxt, &emulate_ops); if (vcpu->pio.string) return EMULATE_DO_MMIO; @@ -1313,7 +1324,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu, } kvm_x86_ops->decache_regs(vcpu); - kvm_x86_ops->set_rflags(vcpu, emulate_ctxt.eflags); + kvm_x86_ops->set_rflags(vcpu, vcpu->emulate_ctxt.eflags); if (vcpu->mmio_is_write) { vcpu->mmio_needed = 0; @@ -2055,7 +2066,7 @@ static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) vcpu->mmio_read_completed = 1; vcpu->mmio_needed = 0; r = emulate_instruction(vcpu, kvm_run, - vcpu->mmio_fault_cr2, 0); + vcpu->mmio_fault_cr2, 0, 1); if (r == EMULATE_DO_MMIO) { /* * Read-modify-write. Back to userspace. diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c index 794d954..f268bd5 100644 --- a/drivers/kvm/svm.c +++ b/drivers/kvm/svm.c @@ -960,7 +960,7 @@ static int pf_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) return 1; } er = emulate_instruction(&svm->vcpu, kvm_run, fault_address, - error_code); + error_code, 0); mutex_unlock(&kvm->lock); switch (er) { @@ -984,7 +984,7 @@ static int ud_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) { int er; - er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0); + er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0, 0); if (er != EMULATE_DONE) inject_ud(&svm->vcpu); @@ -1027,7 +1027,8 @@ static int io_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) string = (io_info & SVM_IOIO_STR_MASK) != 0; if (string) { - if (emulate_instruction(&svm->vcpu, kvm_run, 0, 0) == EMULATE_DO_MMIO) + if (emulate_instruction(&svm->vcpu, + kvm_run, 0, 0, 0) == EMULATE_DO_MMIO) return 0; return 1; } @@ -1086,7 +1087,7 @@ static int cpuid_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) static int emulate_on_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) { - if (emulate_instruction(&svm->vcpu, NULL, 0, 0) != EMULATE_DONE) + if (emulate_instruction(&svm->vcpu, NULL, 0, 0, 0) != EMULATE_DONE) pr_unimpl(&svm->vcpu, "%s: failed\n", __FUNCTION__); return 1; } diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index 47c827d..91768d5d 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -1750,7 +1750,7 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu, * Cause the #SS fault with 0 error code in VM86 mode. */ if (((vec == GP_VECTOR) || (vec == SS_VECTOR)) && err_code == 0) - if (emulate_instruction(vcpu, NULL, 0, 0) == EMULATE_DONE) + if (emulate_instruction(vcpu, NULL, 0, 0, 0) == EMULATE_DONE) return 1; return 0; } @@ -1787,7 +1787,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) } if (is_invalid_opcode(intr_info)) { - er = emulate_instruction(vcpu, kvm_run, 0, 0); + er = emulate_instruction(vcpu, kvm_run, 0, 0, 0); if (er != EMULATE_DONE) vmx_inject_ud(vcpu); @@ -1812,7 +1812,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) return 1; } - er = emulate_instruction(vcpu, kvm_run, cr2, error_code); + er = emulate_instruction(vcpu, kvm_run, cr2, error_code, 0); mutex_unlock(&vcpu->kvm->lock); switch (er) { @@ -1873,7 +1873,8 @@ static int handle_io(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) string = (exit_qualification & 16) != 0; if (string) { - if (emulate_instruction(vcpu, kvm_run, 0, 0) == EMULATE_DO_MMIO) + if (emulate_instruction(vcpu, + kvm_run, 0, 0, 0) == EMULATE_DO_MMIO) return 0; return 1; } diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c index c191093..dc9d2a8 100644 --- a/drivers/kvm/x86_emulate.c +++ b/drivers/kvm/x86_emulate.c @@ -913,10 +913,19 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) unsigned long cr2 = ctxt->cr2; int no_wb = 0; u64 msr_data; + unsigned long saved_eip = 0; unsigned long _eflags = ctxt->eflags; struct decode_cache *c = &ctxt->decode; int rc = 0; + /* Shadow copy of register state. Committed on successful emulation. + * NOTE: we can copy them from vcpu as x86_decode_insn() doesn't + * modify them. + */ + + memcpy(c->regs, ctxt->vcpu->regs, sizeof c->regs); + saved_eip = c->eip; + if ((c->d & ModRM) && (c->modrm_mod != 3)) cr2 = c->modrm_ea; @@ -1250,7 +1259,11 @@ writeback: ctxt->vcpu->rip = c->eip; done: - return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0; + if (rc == X86EMUL_UNHANDLEABLE) { + c->eip = saved_eip; + return -1; + } + return 0; special_insn: if (c->twobyte) @@ -1305,8 +1318,10 @@ push: register_address(ctxt->es_base, c->regs[VCPU_REGS_RDI]), c->rep_prefix, - c->regs[VCPU_REGS_RDX]) == 0) + c->regs[VCPU_REGS_RDX]) == 0) { + c->eip = saved_eip; return -1; + } return 0; case 0x6e: /* outsb */ case 0x6f: /* outsw/outsd */ @@ -1321,8 +1336,10 @@ push: ctxt->ds_base, c->regs[VCPU_REGS_RSI]), c->rep_prefix, - c->regs[VCPU_REGS_RDX]) == 0) + c->regs[VCPU_REGS_RDX]) == 0) { + c->eip = saved_eip; return -1; + } return 0; case 0x70 ... 0x7f: /* jcc (short) */ { int rel = insn_fetch(s8, 1, c->eip); @@ -1711,5 +1728,6 @@ twobyte_special_insn: cannot_emulate: DPRINTF("Cannot emulate %02x\n", c->b); + c->eip = saved_eip; return -1; } -- 2.7.4