From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> If we reset a vcpu on INIT, we so far overwrote dr7 as provided by KVM_SET_GUEST_DEBUG, and we also cleared switch_db_regs unconditionally. Fix this by saving the dr7 used for guest debugging and calculating the effective register value as well as switch_db_regs on any potential change. This will change to focus of the set_guest_debug vendor op to update_dp_bp_intercept. Found while trying to stop on start_secondary. Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> --- arch/x86/include/asm/kvm_host.h | 4 ++-- arch/x86/kvm/svm.c | 23 ++++------------------- arch/x86/kvm/vmx.c | 14 +------------- arch/x86/kvm/x86.c | 26 +++++++++++++++++--------- 4 files changed, 24 insertions(+), 43 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 64adb61..e8baa1c 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -457,6 +457,7 @@ struct kvm_vcpu_arch { unsigned long dr6; unsigned long dr7; unsigned long eff_db[KVM_NR_DB_REGS]; + unsigned long guest_debug_dr7; u64 mcg_cap; u64 mcg_status; @@ -621,8 +622,7 @@ struct kvm_x86_ops { void (*vcpu_load)(struct kvm_vcpu *vcpu, int cpu); void (*vcpu_put)(struct kvm_vcpu *vcpu); - void (*set_guest_debug)(struct kvm_vcpu *vcpu, - struct kvm_guest_debug *dbg); + void (*update_db_bp_intercept)(struct kvm_vcpu *vcpu); int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata); int (*set_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 data); u64 (*get_segment_base)(struct kvm_vcpu *vcpu, int seg); diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 611c728..076064b 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1146,7 +1146,6 @@ static void init_vmcb(struct vcpu_svm *svm) svm_set_efer(&svm->vcpu, 0); save->dr6 = 0xffff0ff0; - save->dr7 = 0x400; kvm_set_rflags(&svm->vcpu, 2); save->rip = 0x0000fff0; svm->vcpu.arch.regs[VCPU_REGS_RIP] = save->rip; @@ -1643,7 +1642,7 @@ static void svm_set_segment(struct kvm_vcpu *vcpu, mark_dirty(svm->vmcb, VMCB_SEG); } -static void update_db_intercept(struct kvm_vcpu *vcpu) +static void update_db_bp_intercept(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); @@ -1663,20 +1662,6 @@ static void update_db_intercept(struct kvm_vcpu *vcpu) vcpu->guest_debug = 0; } -static void svm_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg) -{ - struct vcpu_svm *svm = to_svm(vcpu); - - if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) - svm->vmcb->save.dr7 = dbg->arch.debugreg[7]; - else - svm->vmcb->save.dr7 = vcpu->arch.dr7; - - mark_dirty(svm->vmcb, VMCB_DR); - - update_db_intercept(vcpu); -} - static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd) { if (sd->next_asid > sd->max_asid) { @@ -1748,7 +1733,7 @@ static int db_interception(struct vcpu_svm *svm) if (!(svm->vcpu.guest_debug & KVM_GUESTDBG_SINGLESTEP)) svm->vmcb->save.rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF); - update_db_intercept(&svm->vcpu); + update_db_bp_intercept(&svm->vcpu); } if (svm->vcpu.guest_debug & @@ -3659,7 +3644,7 @@ static void enable_nmi_window(struct kvm_vcpu *vcpu) */ svm->nmi_singlestep = true; svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF); - update_db_intercept(vcpu); + update_db_bp_intercept(vcpu); } static int svm_set_tss_addr(struct kvm *kvm, unsigned int addr) @@ -4259,7 +4244,7 @@ static struct kvm_x86_ops svm_x86_ops = { .vcpu_load = svm_vcpu_load, .vcpu_put = svm_vcpu_put, - .set_guest_debug = svm_guest_debug, + .update_db_bp_intercept = update_db_bp_intercept, .get_msr = svm_get_msr, .set_msr = svm_set_msr, .get_segment_base = svm_get_segment_base, diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index d62b413..b0f7b34 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2286,16 +2286,6 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg) } } -static void set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg) -{ - if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) - vmcs_writel(GUEST_DR7, dbg->arch.debugreg[7]); - else - vmcs_writel(GUEST_DR7, vcpu->arch.dr7); - - update_exception_bitmap(vcpu); -} - static __init int cpu_has_kvm_support(void) { return cpu_has_vmx(); @@ -3959,8 +3949,6 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu) kvm_rip_write(vcpu, 0); kvm_register_write(vcpu, VCPU_REGS_RSP, 0); - vmcs_writel(GUEST_DR7, 0x400); - vmcs_writel(GUEST_GDTR_BASE, 0); vmcs_write32(GUEST_GDTR_LIMIT, 0xffff); @@ -7241,7 +7229,7 @@ static struct kvm_x86_ops vmx_x86_ops = { .vcpu_load = vmx_vcpu_load, .vcpu_put = vmx_vcpu_put, - .set_guest_debug = set_guest_debug, + .update_db_bp_intercept = update_exception_bitmap, .get_msr = vmx_get_msr, .set_msr = vmx_set_msr, .get_segment_base = vmx_get_segment_base, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c4d451e..355d7a8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -692,6 +692,18 @@ unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu) } EXPORT_SYMBOL_GPL(kvm_get_cr8); +static void kvm_update_dr7(struct kvm_vcpu *vcpu) +{ + unsigned long dr7; + + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) + dr7 = vcpu->arch.guest_debug_dr7; + else + dr7 = vcpu->arch.dr7; + kvm_x86_ops->set_dr7(vcpu, dr7); + vcpu->arch.switch_db_regs = (dr7 & DR7_BP_EN_MASK); +} + static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val) { switch (dr) { @@ -717,10 +729,7 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val) if (val & 0xffffffff00000000ULL) return -1; /* #GP */ vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1; - if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) { - kvm_x86_ops->set_dr7(vcpu, vcpu->arch.dr7); - vcpu->arch.switch_db_regs = (val & DR7_BP_EN_MASK); - } + kvm_update_dr7(vcpu); break; } @@ -5853,13 +5862,12 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) { for (i = 0; i < KVM_NR_DB_REGS; ++i) vcpu->arch.eff_db[i] = dbg->arch.debugreg[i]; - vcpu->arch.switch_db_regs = - (dbg->arch.debugreg[7] & DR7_BP_EN_MASK); + vcpu->arch.guest_debug_dr7 = dbg->arch.debugreg[7]; } else { for (i = 0; i < KVM_NR_DB_REGS; i++) vcpu->arch.eff_db[i] = vcpu->arch.db[i]; - vcpu->arch.switch_db_regs = (vcpu->arch.dr7 & DR7_BP_EN_MASK); } + kvm_update_dr7(vcpu); if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) vcpu->arch.singlestep_rip = kvm_rip_read(vcpu) + @@ -5871,7 +5879,7 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, */ kvm_set_rflags(vcpu, rflags); - kvm_x86_ops->set_guest_debug(vcpu, dbg); + kvm_x86_ops->update_db_bp_intercept(vcpu); r = 0; @@ -6043,10 +6051,10 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu) vcpu->arch.nmi_pending = 0; vcpu->arch.nmi_injected = false; - vcpu->arch.switch_db_regs = 0; memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db)); vcpu->arch.dr6 = DR6_FIXED_1; vcpu->arch.dr7 = DR7_FIXED_1; + kvm_update_dr7(vcpu); kvm_make_request(KVM_REQ_EVENT, vcpu); vcpu->arch.apf.msr_val = 0; -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html