From 4d2179e1e9cb74b25a8181a506600d96e15504fb Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Wed, 28 Apr 2010 19:15:42 +0300 Subject: [PATCH] KVM: x86 emulator: handle shadowed registers outside emulator Emulator shouldn't access vcpu directly. Signed-off-by: Gleb Natapov Signed-off-by: Avi Kivity --- arch/x86/kvm/emulate.c | 15 --------------- arch/x86/kvm/x86.c | 14 ++++++++++++-- 2 files changed, 12 insertions(+), 17 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 42cb7d71ff55..97a42e8c00d0 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -941,12 +941,9 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) /* we cannot decode insn before we complete previous rep insn */ WARN_ON(ctxt->restart); - /* Shadow copy of register state. Committed on successful emulation. */ - memset(c, 0, sizeof(struct decode_cache)); c->eip = ctxt->eip; c->fetch.start = c->fetch.end = c->eip; ctxt->cs_base = seg_base(ctxt, ops, VCPU_SREG_CS); - memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs); switch (mode) { case X86EMUL_MODE_REAL: @@ -2486,16 +2483,13 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt, struct decode_cache *c = &ctxt->decode; int rc; - memset(c, 0, sizeof(struct decode_cache)); c->eip = ctxt->eip; - memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs); c->dst.type = OP_NONE; rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason, has_error_code, error_code); if (rc == X86EMUL_CONTINUE) { - memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs); rc = writeback(ctxt, ops); if (rc == X86EMUL_CONTINUE) ctxt->eip = c->eip; @@ -2525,13 +2519,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) ctxt->interruptibility = 0; ctxt->decode.mem_read.pos = 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->arch.regs, sizeof c->regs); - if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) { kvm_queue_exception(ctxt->vcpu, UD_VECTOR); goto done; @@ -3031,8 +3018,6 @@ writeback: * without decoding */ ctxt->decode.mem_read.end = 0; - /* Commit shadow register state. */ - memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs); ctxt->eip = c->eip; done: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 04ca343ee512..21d36081a9d9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3844,7 +3844,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type) { int r, shadow_mask; - struct decode_cache *c; + struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode; kvm_clear_exception_queue(vcpu); vcpu->arch.mmio_fault_cr2 = cr2; @@ -3869,13 +3869,14 @@ int emulate_instruction(struct kvm_vcpu *vcpu, ? X86EMUL_MODE_VM86 : cs_l ? X86EMUL_MODE_PROT64 : cs_db ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16; + memset(c, 0, sizeof(struct decode_cache)); + memcpy(c->regs, vcpu->arch.regs, sizeof c->regs); r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops); trace_kvm_emulate_insn_start(vcpu); /* Only allow emulation of specific instructions on #UD * (namely VMMCALL, sysenter, sysexit, syscall)*/ - c = &vcpu->arch.emulate_ctxt.decode; if (emulation_type & EMULTYPE_TRAP_UD) { if (!c->twobyte) return EMULATE_FAIL; @@ -3916,6 +3917,10 @@ int emulate_instruction(struct kvm_vcpu *vcpu, return EMULATE_DONE; } + /* this is needed for vmware backdor interface to work since it + changes registers values during IO operation */ + memcpy(c->regs, vcpu->arch.regs, sizeof c->regs); + restart: r = x86_emulate_insn(&vcpu->arch.emulate_ctxt, &emulate_ops); @@ -3936,6 +3941,7 @@ restart: shadow_mask = vcpu->arch.emulate_ctxt.interruptibility; kvm_x86_ops->set_interrupt_shadow(vcpu, shadow_mask); kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); + memcpy(vcpu->arch.regs, c->regs, sizeof c->regs); kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip); if (vcpu->arch.pio.count) { @@ -4919,6 +4925,7 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason, bool has_error_code, u32 error_code) { + struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode; int cs_db, cs_l, ret; cache_all_regs(vcpu); @@ -4933,6 +4940,8 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason, ? X86EMUL_MODE_VM86 : cs_l ? X86EMUL_MODE_PROT64 : cs_db ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16; + memset(c, 0, sizeof(struct decode_cache)); + memcpy(c->regs, vcpu->arch.regs, sizeof c->regs); ret = emulator_task_switch(&vcpu->arch.emulate_ctxt, &emulate_ops, tss_selector, reason, has_error_code, @@ -4941,6 +4950,7 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason, if (ret) return EMULATE_FAIL; + memcpy(vcpu->arch.regs, c->regs, sizeof c->regs); kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip); kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); return EMULATE_DONE; -- 2.30.2