Re: [PATCH v5 08/14] KVM: ARM: Emulation framework and CP15 emulation

Russell King - ARM Linux
2013-01-14T18:33:27Z

On Mon, Jan 14, 2013 at 12:38:17PM -0500, Christoffer Dall wrote:
> On Mon, Jan 14, 2013 at 11:36 AM, Russell King - ARM Linux
> <linux@arm.linux.org.uk> wrote:
> > On Tue, Jan 08, 2013 at 01:39:31PM -0500, Christoffer Dall wrote:
> >> + /*
> >> + * Check whether this vcpu requires the cache to be flushed on
> >> + * this physical CPU. This is a consequence of doing dcache
> >> + * operations by set/way on this vcpu. We do it here to be in
> >> + * a non-preemptible section.
> >> + */
> >> + if (cpumask_test_cpu(cpu, &vcpu->arch.require_dcache_flush)) {
> >> + cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);
> >
> > There is cpumask_test_and_clear_cpu() which may be better for this.
>
> nice:
>
> commit d31686fadb74ad564f6a5acabdebe411de86d77d
> Author: Christoffer Dall <c.dall@virtualopensystems.com>
> Date: Mon Jan 14 12:36:53 2013 -0500
>
> KVM: ARM: Use cpumask_test_and_clear_cpu
>
> Nicer shorter cleaner code. Ahhhh.
>
> Cc: Russell King <linux@arm.linux.org.uk>

Great, thanks.

Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>

> Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
>
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index b5c6ab1..fdd4a7c 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -352,10 +352,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> * operations by set/way on this vcpu. We do it here to be in
> * a non-preemptible section.
> */
> - if (cpumask_test_cpu(cpu, &vcpu->arch.require_dcache_flush)) {
> - cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);
> + if (cpumask_test_and_clear_cpu(cpu, &vcpu->arch.require_dcache_flush))
> flush_cache_all(); /* We'd really want v7_flush_dcache_all() */
> - }
>
> kvm_arm_set_running_vcpu(vcpu);
> }
>
> --
>
> Thanks,
> -Christoffer