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SubjectRe: [PATCH v3 3/3] QEMU-AER: Qemu changes to support AER for VFIO-PCI devices
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On Sun, 2013-02-03 at 14:10 +0000, Pandarathil, Vijaymohan R wrote:
> - Create eventfd per vfio device assigned to a guest and register an
> event handler
>
> - This fd is passed to the vfio_pci driver through the SET_IRQ ioctl
>
> - When the device encounters an error, the eventfd is signalled
> and the qemu eventfd handler gets invoked.
>
> - In the handler decide what action to take. Current action taken
> is to terminate the guest.
>
> Signed-off-by: Vijay Mohan Pandarathil <vijaymohan.pandarathil@hp.com>
> ---
> hw/vfio_pci.c | 105 +++++++++++++++++++++++++++++++++++++++++++++
> linux-headers/linux/vfio.h | 1 +
> 2 files changed, 106 insertions(+)
>
> diff --git a/hw/vfio_pci.c b/hw/vfio_pci.c
> index c51ae67..4e2f768 100644
> --- a/hw/vfio_pci.c
> +++ b/hw/vfio_pci.c
> @@ -130,6 +130,8 @@ typedef struct VFIODevice {
> QLIST_ENTRY(VFIODevice) next;
> struct VFIOGroup *group;
> bool reset_works;
> + EventNotifier err_notifier;
> + bool pci_aer;

Re-order these for alignment please. ie:

struct VFIOGroup *group;
EventNotifier err_notifier;
bool reset_works;
bool pci_aer;
> } VFIODevice;
>
> typedef struct VFIOGroup {
> @@ -1922,6 +1924,106 @@ static void vfio_put_device(VFIODevice *vdev)
> }
> }
>
> +static void vfio_err_notifier_handler(void *opaque)
> +{
> + VFIODevice *vdev = opaque;
> +
> + if (!event_notifier_test_and_clear(&vdev->err_notifier)) {
> + return;
> + }
> +
> + /*
> + * TBD. Retrieve the error details and decide what action
> + * needs to be taken. One of the actions could be to pass
> + * the error to the guest and have the guest driver recover
> + * from the error. This requires that PCIe capabilities be
> + * exposed to the guest. At present, we just terminate the
> + * guest to contain the error.
> + */
> +
> + error_report("%s (%04x:%02x:%02x.%x)"
> + "Unrecoverable error detected... Terminating guest\n",
> + __func__, vdev->host.domain, vdev->host.bus,
> + vdev->host.slot, vdev->host.function);
> +
> + hw_error("(%04x:%02x:%02x.%x) Unrecoverable device error\n",
> + vdev->host.domain, vdev->host.bus,
> + vdev->host.slot, vdev->host.function);
> +
> + return;

As Blue Swirl mentions, these returns at the end of void functions are
unnecessary.

> +}
> +
> +static void vfio_register_err_notifier(VFIODevice *vdev)
> +{
> + int ret;
> + int argsz;
> + struct vfio_irq_set *irq_set;
> + int32_t *pfd;
> +
> + if (event_notifier_init(&vdev->err_notifier, 0)) {
> + error_report("vfio: Warning: Unable to init event notifier for error detection\n");
> + return;
> + }
> +
> + argsz = sizeof(*irq_set) + sizeof(*pfd);
> +
> + irq_set = g_malloc0(argsz);
> + irq_set->argsz = argsz;
> + irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
> + VFIO_IRQ_SET_ACTION_TRIGGER;
> + irq_set->index = VFIO_PCI_ERR_IRQ_INDEX;
> + irq_set->start = 0;
> + irq_set->count = 1;
> + pfd = (int32_t *)&irq_set->data;
> +
> + *pfd = event_notifier_get_fd(&vdev->err_notifier);
> + qemu_set_fd_handler(*pfd, vfio_err_notifier_handler, NULL, vdev);
> +
> + ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
> + if (ret) {
> + DPRINTF("vfio: Error notification not supported for the device\n");

We should know this already though, right? Where's our call to
VFIO_DEVICE_GET_IRQ_INFO for this index? I'd expect that should happen
in vfio_get_device where it can set some flag true, then this function
would exit immediately if that flag isn't set. Then by the time we're
here, it's a legitimate error_report if we think this should work and
doesn't.

> + qemu_set_fd_handler(*pfd, NULL, NULL, vdev);
> + event_notifier_cleanup(&vdev->err_notifier);
> + g_free(irq_set);
> + return;
> + }
> + g_free(irq_set);
> + vdev->pci_aer = 1;

bool, so set to true or false.

> + return;
> +}
> +static void vfio_unregister_err_notifier(VFIODevice *vdev)
> +{
> + int argsz;
> + struct vfio_irq_set *irq_set;
> + int32_t *pfd;
> + int ret;
> +
> + if (!vdev->pci_aer) {
> + return;
> + }
> +
> + argsz = sizeof(*irq_set) + sizeof(*pfd);
> +
> + irq_set = g_malloc0(argsz);
> + irq_set->argsz = argsz;
> + irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
> + VFIO_IRQ_SET_ACTION_TRIGGER;
> + irq_set->index = VFIO_PCI_ERR_IRQ_INDEX;
> + irq_set->start = 0;
> + irq_set->count = 1;
> + pfd = (int32_t *)&irq_set->data;
> + *pfd = -1;
> +
> + ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
> + if (ret) {
> + DPRINTF("vfio: Failed to de-assign error fd: %d\n", ret);

This is also a legitimate error_report. In general, if kernel vfio-pci
does or doesn't support a non-critical feature, that's a DPRINTF. If
it's told us the feature is there and something doesn't work while
setting it up, that's an error_report. Thanks,

Alex

> + }
> + g_free(irq_set);
> + qemu_set_fd_handler(event_notifier_get_fd(&vdev->err_notifier),
> + NULL, NULL, vdev);
> + event_notifier_cleanup(&vdev->err_notifier);
> + return;
> +}
> static int vfio_initfn(PCIDevice *pdev)
> {
> VFIODevice *pvdev, *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> @@ -2032,6 +2134,8 @@ static int vfio_initfn(PCIDevice *pdev)
> }
> }
>
> + vfio_register_err_notifier(vdev);
> +
> return 0;
>
> out_teardown:
> @@ -2049,6 +2153,7 @@ static void vfio_exitfn(PCIDevice *pdev)
> VFIODevice *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> VFIOGroup *group = vdev->group;
>
> + vfio_unregister_err_notifier(vdev);
> pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
> vfio_disable_interrupts(vdev);
> if (vdev->intx.mmap_timer) {
> diff --git a/linux-headers/linux/vfio.h b/linux-headers/linux/vfio.h
> index f787b72..6b20849 100644
> --- a/linux-headers/linux/vfio.h
> +++ b/linux-headers/linux/vfio.h
> @@ -310,6 +310,7 @@ enum {
> VFIO_PCI_INTX_IRQ_INDEX,
> VFIO_PCI_MSI_IRQ_INDEX,
> VFIO_PCI_MSIX_IRQ_INDEX,
> + VFIO_PCI_ERR_IRQ_INDEX,
> VFIO_PCI_NUM_IRQS
> };
>





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