On Sun, Jan 04, 2009 at 06:14:44PM +0200, Avi Kivity wrote:
> Allow clients to request notifications when the guest masks or unmasks a
> particular irq line. This complements irq ack notifications, as the guest
> will not ack an irq line that is masked.
>
> Currently implemented for the ioapic only.
>
> Signed-off-by: Avi Kivity <[email protected]>
> ---
> include/linux/kvm_host.h | 17 +++++++++++++++++
> virt/kvm/ioapic.c | 7 ++++++-
> virt/kvm/irq_comm.c | 24 ++++++++++++++++++++++++
> virt/kvm/kvm_main.c | 3 +++
> 4 files changed, 50 insertions(+), 1 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 545a133..43385fa 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -127,6 +127,10 @@ struct kvm {
> struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
> #endif
>
> +#ifdef CONFIG_HAVE_KVM_IRQCHIP
> + struct hlist_head mask_notifier_list;
> +#endif
> +
> #ifdef KVM_ARCH_WANT_MMU_NOTIFIER
> struct mmu_notifier mmu_notifier;
> unsigned long mmu_notifier_seq;
> @@ -320,6 +324,19 @@ struct kvm_assigned_dev_kernel {
> struct pci_dev *dev;
> struct kvm *kvm;
> };
> +
> +struct kvm_irq_mask_notifier {
> + void (*func)(struct kvm_irq_mask_notifier *kimn, int masked);
bool masked?
> + int irq;
> + struct hlist_node link;
> +};
> +
> +void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
> + struct kvm_irq_mask_notifier *kimn);
> +void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
> + struct kvm_irq_mask_notifier *kimn);
> +void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, int mask);
> +
> void kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level);
> void kvm_notify_acked_irq(struct kvm *kvm, unsigned gsi);
> void kvm_register_irq_ack_notifier(struct kvm *kvm,
> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
> index 23b81cf..15b9ddd 100644
> --- a/virt/kvm/ioapic.c
> +++ b/virt/kvm/ioapic.c
> @@ -100,7 +100,7 @@ static void ioapic_service(struct kvm_ioapic *ioapic,
> unsigned int idx)
>
> static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
> {
> - unsigned index;
> + unsigned index, mask_before, mask_after;
>
> switch (ioapic->ioregsel) {
> case IOAPIC_REG_VERSION:
> @@ -120,6 +120,7 @@ static void ioapic_write_indirect(struct kvm_ioapic
> *ioapic, u32 val)
> ioapic_debug("change redir index %x val %x\n", index, val);
> if (index >= IOAPIC_NUM_PINS)
> return;
> + mask_before = ioapic->redirtbl[index].fields.mask;
> if (ioapic->ioregsel & 1) {
> ioapic->redirtbl[index].bits &= 0xffffffff;
> ioapic->redirtbl[index].bits |= (u64) val << 32;
> @@ -128,6 +129,9 @@ static void ioapic_write_indirect(struct kvm_ioapic
> *ioapic, u32 val)
> ioapic->redirtbl[index].bits |= (u32) val;
> ioapic->redirtbl[index].fields.remote_irr = 0;
> }
> + mask_after = ioapic->redirtbl[index].fields.mask;
> + if (mask_before != mask_after)
> + kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after);
This can generate "spurious acks", for example:
- inject irq
- guest masks, mask notifier cleans internal state to "acked".
- guest writes EOI
But I suppose thats fine, since PIT (for example) is getting spurious
acks even without mask notifiers and so has to handle them.
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