KVM: x86: Fix guest debug across vcpu INIT reset
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@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
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zatwierdzone przez
Avi Kivity

rodzic
7a84428af7
commit
c863901075
@@ -692,6 +692,18 @@ unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu)
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}
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EXPORT_SYMBOL_GPL(kvm_get_cr8);
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static void kvm_update_dr7(struct kvm_vcpu *vcpu)
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{
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unsigned long dr7;
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if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
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dr7 = vcpu->arch.guest_debug_dr7;
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else
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dr7 = vcpu->arch.dr7;
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kvm_x86_ops->set_dr7(vcpu, dr7);
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vcpu->arch.switch_db_regs = (dr7 & DR7_BP_EN_MASK);
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}
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static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
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{
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switch (dr) {
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@@ -717,10 +729,7 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
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if (val & 0xffffffff00000000ULL)
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return -1; /* #GP */
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vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
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if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
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kvm_x86_ops->set_dr7(vcpu, vcpu->arch.dr7);
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vcpu->arch.switch_db_regs = (val & DR7_BP_EN_MASK);
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}
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kvm_update_dr7(vcpu);
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break;
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}
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@@ -5851,13 +5860,12 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
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if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
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for (i = 0; i < KVM_NR_DB_REGS; ++i)
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vcpu->arch.eff_db[i] = dbg->arch.debugreg[i];
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vcpu->arch.switch_db_regs =
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(dbg->arch.debugreg[7] & DR7_BP_EN_MASK);
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vcpu->arch.guest_debug_dr7 = dbg->arch.debugreg[7];
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} else {
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for (i = 0; i < KVM_NR_DB_REGS; i++)
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vcpu->arch.eff_db[i] = vcpu->arch.db[i];
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vcpu->arch.switch_db_regs = (vcpu->arch.dr7 & DR7_BP_EN_MASK);
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}
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kvm_update_dr7(vcpu);
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if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
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vcpu->arch.singlestep_rip = kvm_rip_read(vcpu) +
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@@ -5869,7 +5877,7 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
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*/
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kvm_set_rflags(vcpu, rflags);
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kvm_x86_ops->set_guest_debug(vcpu, dbg);
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kvm_x86_ops->update_db_bp_intercept(vcpu);
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r = 0;
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@@ -6045,10 +6053,10 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
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vcpu->arch.nmi_pending = 0;
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vcpu->arch.nmi_injected = false;
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vcpu->arch.switch_db_regs = 0;
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memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
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vcpu->arch.dr6 = DR6_FIXED_1;
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vcpu->arch.dr7 = DR7_FIXED_1;
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kvm_update_dr7(vcpu);
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kvm_make_request(KVM_REQ_EVENT, vcpu);
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vcpu->arch.apf.msr_val = 0;
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