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    Subject[PATCH v5 3/3] QEMU-AER: Qemu changes to support AER for VFIO-PCI devices
    Date

    - 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 stop the guest.

    Signed-off-by: Vijay Mohan Pandarathil <vijaymohan.pandarathil@hp.com>
    ---
    hw/vfio_pci.c | 123 +++++++++++++++++++++++++++++++++++++++++++++
    linux-headers/linux/vfio.h | 1 +
    2 files changed, 124 insertions(+)

    diff --git a/hw/vfio_pci.c b/hw/vfio_pci.c
    index ad9ae36..3c78771 100644
    --- a/hw/vfio_pci.c
    +++ b/hw/vfio_pci.c
    @@ -38,6 +38,7 @@
    #include "qemu/error-report.h"
    #include "qemu/queue.h"
    #include "qemu/range.h"
    +#include "sysemu/sysemu.h"

    /* #define DEBUG_VFIO */
    #ifdef DEBUG_VFIO
    @@ -129,7 +130,9 @@ typedef struct VFIODevice {
    PCIHostDeviceAddress host;
    QLIST_ENTRY(VFIODevice) next;
    struct VFIOGroup *group;
    + EventNotifier err_notifier;
    bool reset_works;
    + bool pci_aer;
    } VFIODevice;

    typedef struct VFIOGroup {
    @@ -1802,6 +1805,7 @@ static int vfio_get_device(VFIOGroup *group, const char *name, VFIODevice *vdev)
    {
    struct vfio_device_info dev_info = { .argsz = sizeof(dev_info) };
    struct vfio_region_info reg_info = { .argsz = sizeof(reg_info) };
    + struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info) };
    int ret, i;

    ret = ioctl(group->fd, VFIO_GROUP_GET_DEVICE_FD, name);
    @@ -1904,6 +1908,18 @@ static int vfio_get_device(VFIOGroup *group, const char *name, VFIODevice *vdev)
    }
    vdev->config_offset = reg_info.offset;

    + irq_info.index = VFIO_PCI_ERR_IRQ_INDEX;
    +
    + ret = ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
    + if (ret) {
    + /* This can fail for an old kernel or legacy PCI dev */
    + DPRINTF("VFIO_DEVICE_GET_IRQ_INFO failure ret=%d\n", ret);
    + ret = 0;
    + } else if (irq_info.count == 1) {
    + vdev->pci_aer = true;
    + } else {
    + error_report("vfio: Warning: Could not enable error recovery for the device\n");
    + }
    error:
    if (ret) {
    QLIST_REMOVE(vdev, next);
    @@ -1925,6 +1941,110 @@ 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. For now, we just terminate the
    + * guest to contain the error.
    + */
    +
    + error_report("%s (%04x:%02x:%02x.%x)"
    + "Unrecoverable error detected...\n"
    + "Please collect any data possible and then kill the guest",
    + __func__, vdev->host.domain, vdev->host.bus,
    + vdev->host.slot, vdev->host.function);
    +
    + vm_stop(RUN_STATE_IO_ERROR);
    +}
    +
    +/*
    + * Registers error notifier for devices supporting error recovery.
    + * If we encounter a failure in this function, we report an error
    + * and continue after disabling error recovery support for the
    + * device.
    + */
    +static void vfio_register_err_notifier(VFIODevice *vdev)
    +{
    + int ret;
    + int argsz;
    + struct vfio_irq_set *irq_set;
    + int32_t *pfd;
    +
    + if (!vdev->pci_aer) {
    + return;
    + }
    +
    + if (event_notifier_init(&vdev->err_notifier, 0)) {
    + error_report("vfio: Warning: Unable to init event notifier for error detection\n");
    + vdev->pci_aer = false;
    + 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) {
    + error_report("vfio: Failed to set up error notification\n");
    + qemu_set_fd_handler(*pfd, NULL, NULL, vdev);
    + event_notifier_cleanup(&vdev->err_notifier);
    + vdev->pci_aer = false;
    + }
    + g_free(irq_set);
    +}
    +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) {
    + error_report("vfio: Failed to de-assign error fd: %d\n", ret);
    + }
    + g_free(irq_set);
    + qemu_set_fd_handler(event_notifier_get_fd(&vdev->err_notifier),
    + NULL, NULL, vdev);
    + event_notifier_cleanup(&vdev->err_notifier);
    +}
    static int vfio_initfn(PCIDevice *pdev)
    {
    VFIODevice *pvdev, *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
    @@ -2035,6 +2155,8 @@ static int vfio_initfn(PCIDevice *pdev)
    }
    }

    + vfio_register_err_notifier(vdev);
    +
    return 0;

    out_teardown:
    @@ -2052,6 +2174,7 @@ 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
    };

    --
    1.7.11.3


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