On Tue, 2012-02-28 at 14:19 +0100, Jan Kiszka wrote:
> PCI 2.3 allows to generically disable IRQ sources at device level. This
> enables us to share legacy IRQs of such devices with other host devices
> when passing them to a guest.
>
> The new IRQ sharing feature introduced here is optional, user space has
> to request it explicitly.
Is this really true? Looks like it's automatic.
> Moreover, user space can inform us about its
> view of PCI_COMMAND_INTX_DISABLE so that we can avoid unmasking the
> interrupt and signaling it if the guest masked it via the virtualized
> PCI config space.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> ---
>
> Changes in v4:
> - Integrated doc changes as proposed by Alex
> - Fixed deassign_host_irq /wrt MSI
> - Fixed kvm_vm_ioctl_set_pci_irq_mask /wrt INTx unmasking of non-2.3
> devices
>
> Documentation/virtual/kvm/api.txt | 41 +++++++
> arch/x86/kvm/x86.c | 1 +
> include/linux/kvm.h | 6 +
> include/linux/kvm_host.h | 2 +
> virt/kvm/assigned-dev.c | 209 +++++++++++++++++++++++++++++++-----
> 5 files changed, 230 insertions(+), 29 deletions(-)
[snip]
> +static int kvm_vm_ioctl_set_pci_irq_mask(struct kvm *kvm,
> + struct kvm_assigned_pci_dev *assigned_dev)
> +{
> + int r = 0;
> + struct kvm_assigned_dev_kernel *match;
> +
> + mutex_lock(&kvm->lock);
> +
> + match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
> + assigned_dev->assigned_dev_id);
> + if (!match) {
> + r = -ENODEV;
> + goto out;
> + }
> +
> + mutex_lock(&match->intx_mask_lock);
> +
> + match->flags &= ~KVM_DEV_ASSIGN_MASK_INTX;
> + match->flags |= assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX;
> +
> + if (match->irq_requested_type & KVM_DEV_IRQ_GUEST_INTX) {
> + if (assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX) {
> + kvm_set_irq(match->kvm, match->irq_source_id,
> + match->guest_irq, 0);
> + /*
> + * Masking at hardware-level is performed on demand,
> + * i.e. when an IRQ actually arrives at the host.
> + */
> + } else if (!(assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
> + /*
> + * Unmask the IRQ line if required. Unmasking at
> + * device level will be performed by user space.
> + */
> + spin_lock_irq(&match->intx_lock);
> + if (match->host_irq_disabled) {
> + enable_irq(match->host_irq);
> + match->host_irq_disabled = false;
> + }
> + spin_unlock_irq(&match->intx_lock);
This still looks broken. If we start with a PCI 2.3 device with INTx
disabled, how does this ever kick start to get another interrupt?
Shouldn't we just call kvm_assigned_dev_ack_irq() here and handle both
INTx modes? Thanks,
Alex
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
