[36/42] KVM: x86: Rework guest single-step flag injection and filtering

Message ID	1258373983-8693-37-git-send-email-avi@redhat.com (mailing list archive)
State	New, archived
Headers	show Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id nAGCTktQ020988 for <patchwork-kvm@patchwork.kernel.org>; Mon, 16 Nov 2009 12:29:49 GMT From: Avi Kivity <avi@redhat.com> To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org Subject: [PATCH 36/42] KVM: x86: Rework guest single-step flag injection and filtering Date: Mon, 16 Nov 2009 14:19:37 +0200 Message-Id: <1258373983-8693-37-git-send-email-avi@redhat.com> In-Reply-To: <1258373983-8693-1-git-send-email-avi@redhat.com> References: <1258373983-8693-1-git-send-email-avi@redhat.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index e7f8708..179a919 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -614,6 +614,9 @@ void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l); int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata); int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data); +unsigned long kvm_get_rflags(struct kvm_vcpu *vcpu); +void kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags); + void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr); void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code); void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long cr2, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4693f91..385cd0a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -235,6 +235,25 @@ bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl) } EXPORT_SYMBOL_GPL(kvm_require_cpl); +unsigned long kvm_get_rflags(struct kvm_vcpu *vcpu) +{ + unsigned long rflags; + + rflags = kvm_x86_ops->get_rflags(vcpu); + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) + rflags &= ~(unsigned long)(X86_EFLAGS_TF | X86_EFLAGS_RF); + return rflags; +} +EXPORT_SYMBOL_GPL(kvm_get_rflags); + +void kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags) +{ + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) + rflags |= X86_EFLAGS_TF | X86_EFLAGS_RF; + kvm_x86_ops->set_rflags(vcpu, rflags); +} +EXPORT_SYMBOL_GPL(kvm_set_rflags); + /* * Load the pae pdptrs. Return true is they are all valid. */ @@ -2777,7 +2796,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu, kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l); vcpu->arch.emulate_ctxt.vcpu = vcpu; - vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu); + vcpu->arch.emulate_ctxt.eflags = kvm_get_rflags(vcpu); vcpu->arch.emulate_ctxt.mode = (vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM) ? X86EMUL_MODE_REAL : cs_l @@ -2855,7 +2874,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu, return EMULATE_DO_MMIO; } - kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); + kvm_set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); if (vcpu->mmio_is_write) { vcpu->mmio_needed = 0; @@ -3291,7 +3310,7 @@ void realmode_lmsw(struct kvm_vcpu *vcpu, unsigned long msw, unsigned long *rflags) { kvm_lmsw(vcpu, msw); - *rflags = kvm_x86_ops->get_rflags(vcpu); + *rflags = kvm_get_rflags(vcpu); } unsigned long realmode_get_cr(struct kvm_vcpu *vcpu, int cr) @@ -3329,7 +3348,7 @@ void realmode_set_cr(struct kvm_vcpu *vcpu, int cr, unsigned long val, switch (cr) { case 0: kvm_set_cr0(vcpu, mk_cr_64(vcpu->arch.cr0, val)); - *rflags = kvm_x86_ops->get_rflags(vcpu); + *rflags = kvm_get_rflags(vcpu); break; case 2: vcpu->arch.cr2 = val; @@ -3460,7 +3479,7 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu) { struct kvm_run *kvm_run = vcpu->run; - kvm_run->if_flag = (kvm_x86_ops->get_rflags(vcpu) & X86_EFLAGS_IF) != 0; + kvm_run->if_flag = (kvm_get_rflags(vcpu) & X86_EFLAGS_IF) != 0; kvm_run->cr8 = kvm_get_cr8(vcpu); kvm_run->apic_base = kvm_get_apic_base(vcpu); if (irqchip_in_kernel(vcpu->kvm)) @@ -3840,13 +3859,7 @@ int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs) #endif regs->rip = kvm_rip_read(vcpu); - regs->rflags = kvm_x86_ops->get_rflags(vcpu); - - /* - * Don't leak debug flags in case they were set for guest debugging - */ - if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) - regs->rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF); + regs->rflags = kvm_get_rflags(vcpu); vcpu_put(vcpu); @@ -3874,12 +3887,10 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs) kvm_register_write(vcpu, VCPU_REGS_R13, regs->r13); kvm_register_write(vcpu, VCPU_REGS_R14, regs->r14); kvm_register_write(vcpu, VCPU_REGS_R15, regs->r15); - #endif kvm_rip_write(vcpu, regs->rip); - kvm_x86_ops->set_rflags(vcpu, regs->rflags); - + kvm_set_rflags(vcpu, regs->rflags); vcpu->arch.exception.pending = false; @@ -4098,7 +4109,7 @@ static int is_vm86_segment(struct kvm_vcpu *vcpu, int seg) { return (seg != VCPU_SREG_LDTR) && (seg != VCPU_SREG_TR) && - (kvm_x86_ops->get_rflags(vcpu) & X86_EFLAGS_VM); + (kvm_get_rflags(vcpu) & X86_EFLAGS_VM); } int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, @@ -4126,7 +4137,7 @@ static void save_state_to_tss32(struct kvm_vcpu *vcpu, { tss->cr3 = vcpu->arch.cr3; tss->eip = kvm_rip_read(vcpu); - tss->eflags = kvm_x86_ops->get_rflags(vcpu); + tss->eflags = kvm_get_rflags(vcpu); tss->eax = kvm_register_read(vcpu, VCPU_REGS_RAX); tss->ecx = kvm_register_read(vcpu, VCPU_REGS_RCX); tss->edx = kvm_register_read(vcpu, VCPU_REGS_RDX); @@ -4150,7 +4161,7 @@ static int load_state_from_tss32(struct kvm_vcpu *vcpu, kvm_set_cr3(vcpu, tss->cr3); kvm_rip_write(vcpu, tss->eip); - kvm_x86_ops->set_rflags(vcpu, tss->eflags | 2); + kvm_set_rflags(vcpu, tss->eflags | 2); kvm_register_write(vcpu, VCPU_REGS_RAX, tss->eax); kvm_register_write(vcpu, VCPU_REGS_RCX, tss->ecx); @@ -4188,7 +4199,7 @@ static void save_state_to_tss16(struct kvm_vcpu *vcpu, struct tss_segment_16 *tss) { tss->ip = kvm_rip_read(vcpu); - tss->flag = kvm_x86_ops->get_rflags(vcpu); + tss->flag = kvm_get_rflags(vcpu); tss->ax = kvm_register_read(vcpu, VCPU_REGS_RAX); tss->cx = kvm_register_read(vcpu, VCPU_REGS_RCX); tss->dx = kvm_register_read(vcpu, VCPU_REGS_RDX); @@ -4209,7 +4220,7 @@ static int load_state_from_tss16(struct kvm_vcpu *vcpu, struct tss_segment_16 *tss) { kvm_rip_write(vcpu, tss->ip); - kvm_x86_ops->set_rflags(vcpu, tss->flag | 2); + kvm_set_rflags(vcpu, tss->flag | 2); kvm_register_write(vcpu, VCPU_REGS_RAX, tss->ax); kvm_register_write(vcpu, VCPU_REGS_RCX, tss->cx); kvm_register_write(vcpu, VCPU_REGS_RDX, tss->dx); @@ -4355,8 +4366,8 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason) } if (reason == TASK_SWITCH_IRET) { - u32 eflags = kvm_x86_ops->get_rflags(vcpu); - kvm_x86_ops->set_rflags(vcpu, eflags & ~X86_EFLAGS_NT); + u32 eflags = kvm_get_rflags(vcpu); + kvm_set_rflags(vcpu, eflags & ~X86_EFLAGS_NT); } /* set back link to prev task only if NT bit is set in eflags @@ -4377,8 +4388,8 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason) old_tss_base, &nseg_desc); if (reason == TASK_SWITCH_CALL || reason == TASK_SWITCH_GATE) { - u32 eflags = kvm_x86_ops->get_rflags(vcpu); - kvm_x86_ops->set_rflags(vcpu, eflags | X86_EFLAGS_NT); + u32 eflags = kvm_get_rflags(vcpu); + kvm_set_rflags(vcpu, eflags | X86_EFLAGS_NT); } if (reason != TASK_SWITCH_IRET) { @@ -4473,12 +4484,15 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg) { unsigned long rflags; - int old_debug; int i; vcpu_load(vcpu); - old_debug = vcpu->guest_debug; + /* + * Read rflags as long as potentially injected trace flags are still + * filtered out. + */ + rflags = kvm_get_rflags(vcpu); vcpu->guest_debug = dbg->control; if (!(vcpu->guest_debug & KVM_GUESTDBG_ENABLE)) @@ -4495,12 +4509,11 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, vcpu->arch.switch_db_regs = (vcpu->arch.dr7 & DR7_BP_EN_MASK); } - rflags = kvm_x86_ops->get_rflags(vcpu); - if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) - rflags |= X86_EFLAGS_TF | X86_EFLAGS_RF; - else if (old_debug & KVM_GUESTDBG_SINGLESTEP) - rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF); - kvm_x86_ops->set_rflags(vcpu, rflags); + /* + * Trigger an rflags update that will inject or remove the trace + * flags. + */ + kvm_set_rflags(vcpu, rflags); kvm_x86_ops->set_guest_debug(vcpu, dbg);

[36/42] KVM: x86: Rework guest single-step flag injection and filtering

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