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Re: x86: Hardware breakpoints are not always triggered

From Paolo Bonzini <pbonzini@redhat.com>
Newsgroups linux.kernel
Subject Re: x86: Hardware breakpoints are not always triggered
Date 2016-01-28 22:40 +0100
Message-ID <qW2si-Yt-13@gated-at.bofh.it> (permalink)
References <qVQhs-Jf-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 28/01/2016 09:31, Andrey Wagin wrote:
> I tried to print drX registers after a break-point. Looks like they
> are set correctly.

Can you try this KVM patch?

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index c13a64b7d789..32bae1c70a50 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1612,6 +1612,7 @@ static void svm_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
 	vcpu->arch.dr7 = svm->vmcb->save.dr7;
 
 	vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_WONT_EXIT;
+	vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD;
 	set_dr_intercepts(svm);
 }
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e2951b6edbbc..505a4663b9f4 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5659,6 +5659,7 @@ static void vmx_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
 	vcpu->arch.dr7 = vmcs_readl(GUEST_DR7);
 
 	vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_WONT_EXIT;
+	vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD;
 
 	cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
 	cpu_based_vm_exec_control |= CPU_BASED_MOV_DR_EXITING;

Paolo

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Thread

x86: Hardware breakpoints are not always triggered Andrey Wagin <avagin@gmail.com> - 2016-01-28 09:40 +0100
  Re: x86: Hardware breakpoints are not always triggered Jan Kiszka <jan.kiszka@siemens.com> - 2016-01-28 12:10 +0100
  Re: x86: Hardware breakpoints are not always triggered Oleg Nesterov <oleg@redhat.com> - 2016-01-28 22:00 +0100
    Re: x86: Hardware breakpoints are not always triggered Paolo Bonzini <pbonzini@redhat.com> - 2016-01-28 22:30 +0100
    Re: x86: Hardware breakpoints are not always triggered Oleg Nesterov <oleg@redhat.com> - 2016-01-28 23:10 +0100
  Re: x86: Hardware breakpoints are not always triggered Paolo Bonzini <pbonzini@redhat.com> - 2016-01-28 22:40 +0100
    Re: x86: Hardware breakpoints are not always triggered Andrey Wagin <avagin@gmail.com> - 2016-01-28 23:50 +0100
      Re: [CRIU] x86: Hardware breakpoints are not always triggered Andrew Vagin <avagin@virtuozzo.com> - 2016-01-29 23:30 +0100
        Re: [CRIU] x86: Hardware breakpoints are not always triggered Paolo Bonzini <pbonzini@redhat.com> - 2016-01-31 12:10 +0100
          Re: [CRIU] x86: Hardware breakpoints are not always triggered Nadav Amit <nadav.amit@gmail.com> - 2016-02-03 19:20 +0100
            Re: [CRIU] x86: Hardware breakpoints are not always triggered Nadav Amit <nadav.amit@gmail.com> - 2016-02-04 00:40 +0100
              Re: [CRIU] x86: Hardware breakpoints are not always triggered Paolo Bonzini <pbonzini@redhat.com> - 2016-02-04 12:30 +0100

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