| Message ID | 20200508203643.85477-2-jmattson@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Pin the hrtimer used for VMX-preemption timer emulation | expand |
LOL, love the shortlog :-) On Fri, May 08, 2020 at 01:36:41PM -0700, Jim Mattson wrote: > The PINNED bit is ignored by hrtimer_init. It is only considered when > starting the timer. > > When the hrtimer isn't pinned to the same logical processor as the > vCPU thread to be interrupted, the emulated VMX-preemption timer > often fails to adhere to the architectural specification. > > Fixes: f15a75eedc18e ("KVM: nVMX: make emulated nested preemption timer pinned") > Signed-off-by: Jim Mattson <jmattson@google.com> > Reviewed-by: Peter Shier <pshier@google.com> > Reviewed-by: Oliver Upton <oupton@google.com> > --- > arch/x86/kvm/vmx/nested.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c > index fd78ffbde644..1f7fe6f47cbc 100644 > --- a/arch/x86/kvm/vmx/nested.c > +++ b/arch/x86/kvm/vmx/nested.c > @@ -2041,7 +2041,7 @@ static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu) > preemption_timeout *= 1000000; > do_div(preemption_timeout, vcpu->arch.virtual_tsc_khz); > hrtimer_start(&vmx->nested.preemption_timer, > - ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL); > + ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL_PINNED); > } > > static u64 nested_vmx_calc_efer(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12) > -- > 2.26.2.645.ge9eca65c58-goog >
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index fd78ffbde644..1f7fe6f47cbc 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2041,7 +2041,7 @@ static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu) preemption_timeout *= 1000000; do_div(preemption_timeout, vcpu->arch.virtual_tsc_khz); hrtimer_start(&vmx->nested.preemption_timer, - ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL); + ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL_PINNED); } static u64 nested_vmx_calc_efer(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
The PINNED bit is ignored by hrtimer_init. It is only considered when starting the timer. When the hrtimer isn't pinned to the same logical processor as the vCPU thread to be interrupted, the emulated VMX-preemption timer often fails to adhere to the architectural specification. Fixes: f15a75eedc18e ("KVM: nVMX: make emulated nested preemption timer pinned") Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Peter Shier <pshier@google.com> Reviewed-by: Oliver Upton <oupton@google.com> --- arch/x86/kvm/vmx/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)