Thanks Stephen,
On Wed, Jan 3, 2018 at 3:38 AM, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> Hi all,
>
> Today's linux-next merge of the kvm-arm tree got a conflict in:
>
> virt/kvm/arm/arch_timer.c
>
> between commit:
>
> 36e5cfd410ad ("KVM: arm/arm64: Properly handle arch-timer IRQs after vtimer_save_state")
>
> from Linus' tree and commit:
>
> 70450a9fbe06 ("KVM: arm/arm64: Don't cache the timer IRQ level")
>
> from the kvm-arm tree.
>
> I fixed it up (I think - see below) and can carry the fix as necessary.
> This is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
The resolution looks correct to me.
cc'ing the KVM maintainers in case they want to merge kvm/master into
kvm/next to avoid the conflict going up to Linus.
Thanks,
-Christoffer
>
> diff --cc virt/kvm/arm/arch_timer.c
> index cc29a8148328,cfcd0323deab..000000000000
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@@ -92,27 -92,19 +92,26 @@@ static irqreturn_t kvm_arch_timer_handl
> {
> struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id;
> struct arch_timer_context *vtimer;
> + u32 cnt_ctl;
>
> - if (!vcpu) {
> - pr_warn_once("Spurious arch timer IRQ on non-VCPU thread\n");
> - return IRQ_NONE;
> - }
> - vtimer = vcpu_vtimer(vcpu);
> + /*
> + * We may see a timer interrupt after vcpu_put() has been called which
> + * sets the CPU's vcpu pointer to NULL, because even though the timer
> + * has been disabled in vtimer_save_state(), the hardware interrupt
> + * signal may not have been retired from the interrupt controller yet.
> + */
> + if (!vcpu)
> + return IRQ_HANDLED;
>
> - vtimer->cnt_ctl = read_sysreg_el0(cntv_ctl);
> - if (kvm_timer_irq_can_fire(vtimer))
> + vtimer = vcpu_vtimer(vcpu);
> - if (!vtimer->irq.level) {
> - cnt_ctl = read_sysreg_el0(cntv_ctl);
> - cnt_ctl &= ARCH_TIMER_CTRL_ENABLE | ARCH_TIMER_CTRL_IT_STAT |
> - ARCH_TIMER_CTRL_IT_MASK;
> - if (cnt_ctl == (ARCH_TIMER_CTRL_ENABLE | ARCH_TIMER_CTRL_IT_STAT))
> - kvm_timer_update_irq(vcpu, true, vtimer);
> - }
> -
> - if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
> ++ cnt_ctl = read_sysreg_el0(cntv_ctl);
> ++ cnt_ctl &= ARCH_TIMER_CTRL_ENABLE | ARCH_TIMER_CTRL_IT_STAT |
> ++ ARCH_TIMER_CTRL_IT_MASK;
> ++ if (cnt_ctl == (ARCH_TIMER_CTRL_ENABLE | ARCH_TIMER_CTRL_IT_STAT))
> + kvm_timer_update_irq(vcpu, true, vtimer);
> +
> + if (static_branch_unlikely(&userspace_irqchip_in_use) &&
> + unlikely(!irqchip_in_kernel(vcpu->kvm)))
> kvm_vtimer_update_mask_user(vcpu);
>
> return IRQ_HANDLED;
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