Message ID | 20180302105156.19506-1-lvivier@redhat.com (mailing list archive) |
---|---|
State | Accepted |
Headers | show |
Series | KVM: PPC: Book3S HV: Fix guest time accounting with VIRT_CPU_ACCOUNTING_GEN | expand |
On 02/03/2018 11:51, Laurent Vivier wrote: > Since commit 8b24e69fc47e ("KVM: PPC: Book3S HV: Close race with testing > for signals on guest entry"), if CONFIG_VIRT_CPU_ACCOUNTING_GEN is set, the > guest time is not accounted to guest time and user time, but instead to > system time. > > This is because guest_enter()/guest_exit() are called while interrupts > are disabled and the tick counter cannot be updated between them. > > To fix that, move guest_exit() after local_irq_enable(), and as > guest_enter() is called with IRQ disabled, calls guest_enter_irqoff() > instead. > > Fixes: 8b24e69fc47e > ("KVM: PPC: Book3S HV: Close race with testing for signals on guest entry") > Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/powerpc/kvm/book3s_hv.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 89707354c2ef..8274c2807202 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -2885,7 +2885,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc) > */ > trace_hardirqs_on(); > > - guest_enter(); > + guest_enter_irqoff(); > > srcu_idx = srcu_read_lock(&vc->kvm->srcu); > > @@ -2893,8 +2893,6 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc) > > srcu_read_unlock(&vc->kvm->srcu, srcu_idx); > > - guest_exit(); > - > trace_hardirqs_off(); > set_irq_happened(trap); > > @@ -2937,6 +2935,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc) > kvmppc_set_host_core(pcpu); > > local_irq_enable(); > + guest_exit(); > > /* Let secondaries go back to the offline loop */ > for (i = 0; i < controlled_threads; ++i) { >
On Fri, Mar 02, 2018 at 11:51:56AM +0100, Laurent Vivier wrote: > Since commit 8b24e69fc47e ("KVM: PPC: Book3S HV: Close race with testing > for signals on guest entry"), if CONFIG_VIRT_CPU_ACCOUNTING_GEN is set, the > guest time is not accounted to guest time and user time, but instead to > system time. > > This is because guest_enter()/guest_exit() are called while interrupts > are disabled and the tick counter cannot be updated between them. > > To fix that, move guest_exit() after local_irq_enable(), and as > guest_enter() is called with IRQ disabled, calls guest_enter_irqoff() > instead. > > Fixes: 8b24e69fc47e > ("KVM: PPC: Book3S HV: Close race with testing for signals on guest entry") > Signed-off-by: Laurent Vivier <lvivier@redhat.com> Thanks, applied to my kvm-ppc-fixes branch. Paul.
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 89707354c2ef..8274c2807202 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -2885,7 +2885,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc) */ trace_hardirqs_on(); - guest_enter(); + guest_enter_irqoff(); srcu_idx = srcu_read_lock(&vc->kvm->srcu); @@ -2893,8 +2893,6 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc) srcu_read_unlock(&vc->kvm->srcu, srcu_idx); - guest_exit(); - trace_hardirqs_off(); set_irq_happened(trap); @@ -2937,6 +2935,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc) kvmppc_set_host_core(pcpu); local_irq_enable(); + guest_exit(); /* Let secondaries go back to the offline loop */ for (i = 0; i < controlled_threads; ++i) {
Since commit 8b24e69fc47e ("KVM: PPC: Book3S HV: Close race with testing for signals on guest entry"), if CONFIG_VIRT_CPU_ACCOUNTING_GEN is set, the guest time is not accounted to guest time and user time, but instead to system time. This is because guest_enter()/guest_exit() are called while interrupts are disabled and the tick counter cannot be updated between them. To fix that, move guest_exit() after local_irq_enable(), and as guest_enter() is called with IRQ disabled, calls guest_enter_irqoff() instead. Fixes: 8b24e69fc47e ("KVM: PPC: Book3S HV: Close race with testing for signals on guest entry") Signed-off-by: Laurent Vivier <lvivier@redhat.com> --- arch/powerpc/kvm/book3s_hv.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)