On Thu, 17 Oct 2019 16:42:16 +1100
David Gibson <da...@gibson.dropbear.id.au> wrote:
> VFIO PCI devices already respond to the pci intx routing notifier, in order
> to update kernel irqchip mappings when routing is updated. However this
> won't handle the case where the irqchip itself is replaced by a different
> model while retaining the same routing. This case can happen on
> the pseries machine type due to PAPR feature negotiation.
>
> To handle that case, add a handler for the irqchip change notifier, which
> does much the same thing as the routing notifier, but is unconditional,
> rather than being a no-op when the routing hasn't changed.
>
> Cc: Alex Williamson <alex.william...@redhat.com>
> Cc: Alexey Kardashevskiy <a...@ozlabs.ru>
>
> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> hw/vfio/pci.c | 12 ++++++++++++
> hw/vfio/pci.h | 2 ++
> 2 files changed, 14 insertions(+)
>
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 529ad13908..6aa806baff 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -255,6 +255,14 @@ static void vfio_intx_routing_notifier(PCIDevice *pdev)
> }
> }
>
> +static void vfio_irqchip_change(Notifier *notify, void *data)
> +{
> + VFIOPCIDevice *vdev = container_of(notify, VFIOPCIDevice,
> + irqchip_change_notifier);
> +
> + vfio_intx_update(vdev, &vdev->intx.route);
> +}
> +
> static int vfio_intx_enable(VFIOPCIDevice *vdev, Error **errp)
> {
> uint8_t pin = vfio_pci_read_config(&vdev->pdev, PCI_INTERRUPT_PIN, 1);
> @@ -2960,6 +2968,8 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
> vfio_intx_mmap_enable,
> vdev);
> pci_device_set_intx_routing_notifier(&vdev->pdev,
> vfio_intx_routing_notifier);
> + vdev->irqchip_change_notifier.notify = vfio_irqchip_change;
> + kvm_irqchip_add_change_notifier(&vdev->irqchip_change_notifier);
> ret = vfio_intx_enable(vdev, errp);
> if (ret) {
> goto out_teardown;
> @@ -3009,6 +3019,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>
> out_teardown:
> pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
> + kvm_irqchip_remove_change_notifier(&vdev->irqchip_change_notifier);
We can get here without having added the irqchip notifier and I don't
think QLIST_REMOVE is very friendly with gratuitous calls.
> vfio_teardown_msi(vdev);
> vfio_bars_exit(vdev);
> error:
> @@ -3042,6 +3053,7 @@ static void vfio_exitfn(PCIDevice *pdev)
> vfio_unregister_req_notifier(vdev);
> vfio_unregister_err_notifier(vdev);
> pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
> + kvm_irqchip_remove_change_notifier(&vdev->irqchip_change_notifier);
Same here. Otherwise the approach looks sane to me. Thanks,
Alex
> vfio_disable_interrupts(vdev);
> if (vdev->intx.mmap_timer) {
> timer_free(vdev->intx.mmap_timer);
> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> index 834a90d646..11324f28ce 100644
> --- a/hw/vfio/pci.h
> +++ b/hw/vfio/pci.h
> @@ -168,6 +168,8 @@ typedef struct VFIOPCIDevice {
> bool no_vfio_ioeventfd;
> bool enable_ramfb;
> VFIODisplay *dpy;
> +
> + Notifier irqchip_change_notifier;
> } VFIOPCIDevice;
>
> uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len);
