| Message ID | 1412287806-16016-2-git-send-email-namit@cs.technion.ac.il (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2014-10-03 01:10+0300, Nadav Amit: > DR7.LE should be cleared during task-switch. This feature is poorly documented. > For reference, see: > http://pdos.csail.mit.edu/6.828/2005/readings/i386/s12_02.htm SDM [17.2.4]: This feature is not supported in the P6 family processors, later IA-32 processors, and Intel 64 processors. AMD [2:13.1.1.4]: This bit is ignored by implementations of the AMD64 architecture. Intel's formulation could mean that it isn't even zeroed, but if current hardware behaves like that, > Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> > --- Reviewed-by: Radim Kr?má? <rkrcmar@redhat.com> (It shouldn't change a thing.) > arch/x86/kvm/vmx.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 04fa1b8..4190eb5 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -5483,7 +5483,7 @@ static int handle_task_switch(struct kvm_vcpu *vcpu) > } > > /* clear all local breakpoint enable flags */ > - vmcs_writel(GUEST_DR7, vmcs_readl(GUEST_DR7) & ~0x55); > + vmcs_writel(GUEST_DR7, vmcs_readl(GUEST_DR7) & ~0x155); > > /* > * TODO: What about debug traps on tss switch? > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 04fa1b8..4190eb5 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5483,7 +5483,7 @@ static int handle_task_switch(struct kvm_vcpu *vcpu) } /* clear all local breakpoint enable flags */ - vmcs_writel(GUEST_DR7, vmcs_readl(GUEST_DR7) & ~0x55); + vmcs_writel(GUEST_DR7, vmcs_readl(GUEST_DR7) & ~0x155); /* * TODO: What about debug traps on tss switch?
DR7.LE should be cleared during task-switch. This feature is poorly documented. For reference, see: http://pdos.csail.mit.edu/6.828/2005/readings/i386/s12_02.htm Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> --- arch/x86/kvm/vmx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)