From: Paolo Bonzini <pbonzini@redhat.com>
To: Bandan Das <bsd@redhat.com>, Jan Kiszka <jan.kiszka@siemens.com>
Cc: kvm <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 4/5] KVM: nVMX: Allow to disable VM_{ENTRY_LOAD,EXIT_SAVE}_DEBUG_CONTROLS
Date: Tue, 17 Jun 2014 07:18:43 +0200 [thread overview]
Message-ID: <539FCFB3.8030304@redhat.com> (raw)
In-Reply-To: <jpg7g4g4wkw.fsf@nelium.bos.redhat.com>
Il 16/06/2014 19:02, Bandan Das ha scritto:
> > - vmcs_write64(GUEST_IA32_DEBUGCTL, vmcs12->guest_ia32_debugctl);
> > + if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS) {
> > + kvm_set_dr(vcpu, 7, vmcs12->guest_dr7);
> > + vmcs_write64(GUEST_IA32_DEBUGCTL, vmcs12->guest_ia32_debugctl);
> > + } else {
> > + kvm_set_dr(vcpu, 7, vcpu->arch.dr7);
> > + vmcs_write64(GUEST_IA32_DEBUGCTL, vmx->nested.vmcs01_debugctl);
> > + }
>
> (I guess I don't understand DEBUGCTLS enough) vmcs01_debugctl is used by
> L0 to run L1, and if L1 hasn't set VM_ENTRY_LOAD_DEBUG_CONTROLS for L2,
> why do we need the GUEST_IA32_DEBUGCTL vmwrite in the "else" case ?
Beause we always set VM_ENTRY_LOAD_DEBUG_CONTROLS in the VMCS02, so we
must always fill in GUEST_IA32_DEBUGCTL of the VMCS02. Depending on the
VMCS12's VM_ENTRY_LOAD_DEBUG_CONTROLS, the field comes from either
VMCS01 or VMCS12.
Paolo
next prev parent reply other threads:[~2014-06-17 5:18 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-16 11:59 [PATCH v2 0/5] KVM: nVMX: Small fixes improving emulation accuracy Jan Kiszka
2014-06-16 11:59 ` [PATCH v2 1/5] KVM: nVMX: Advertise support for MSR_IA32_VMX_TRUE_*_CTLS Jan Kiszka
2014-06-16 16:54 ` Bandan Das
2014-06-17 6:13 ` Jan Kiszka
2014-06-16 11:59 ` [PATCH v2 2/5] KVM: nVMX: Allow to disable CR3 access interception Jan Kiszka
2014-06-16 11:59 ` [PATCH v2 3/5] KVM: nVMX: Fix returned value of MSR_IA32_VMX_PROCBASED_CTLS Jan Kiszka
2014-06-16 16:56 ` Bandan Das
2014-06-17 6:14 ` Jan Kiszka
2014-06-16 11:59 ` [PATCH v2 4/5] KVM: nVMX: Allow to disable VM_{ENTRY_LOAD,EXIT_SAVE}_DEBUG_CONTROLS Jan Kiszka
2014-06-16 17:02 ` Bandan Das
2014-06-17 5:18 ` Paolo Bonzini [this message]
2014-06-16 11:59 ` [PATCH v2 5/5] KVM: nVMX: Fix returned value of MSR_IA32_VMX_VMCS_ENUM Jan Kiszka
2014-06-16 15:21 ` [PATCH v2 0/5] KVM: nVMX: Small fixes improving emulation accuracy Paolo Bonzini
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