| Message ID | 20220304135914.1464721-1-maz@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Only open the interrupt window on exit due to an interrupt | expand |
On Fri, Mar 04, 2022 at 01:59:14PM +0000, Marc Zyngier wrote: > Now that we properly account for interrupts taken whilst the guest > was running, it becomes obvious that there is no need to open > this accounting window if we didn't exit because of an interrupt. > > This saves a number of system register accesses and other barriers > if we exited for any other reason (such as a trap, for example). > > Signed-off-by: Marc Zyngier <maz@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Mark. > --- > arch/arm64/kvm/arm.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index fefd5774ab55..f49ebdd9c990 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -887,9 +887,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) > * context synchronization event) is necessary to ensure that > * pending interrupts are taken. > */ > - local_irq_enable(); > - isb(); > - local_irq_disable(); > + if (ARM_EXCEPTION_CODE(ret) == ARM_EXCEPTION_IRQ) { > + local_irq_enable(); > + isb(); > + local_irq_disable(); > + } > > guest_timing_exit_irqoff(); > > -- > 2.34.1 >
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index fefd5774ab55..f49ebdd9c990 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -887,9 +887,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) * context synchronization event) is necessary to ensure that * pending interrupts are taken. */ - local_irq_enable(); - isb(); - local_irq_disable(); + if (ARM_EXCEPTION_CODE(ret) == ARM_EXCEPTION_IRQ) { + local_irq_enable(); + isb(); + local_irq_disable(); + } guest_timing_exit_irqoff();
Now that we properly account for interrupts taken whilst the guest was running, it becomes obvious that there is no need to open this accounting window if we didn't exit because of an interrupt. This saves a number of system register accesses and other barriers if we exited for any other reason (such as a trap, for example). Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kvm/arm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)