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Message-ID: <1373925066.8441.272.camel@ul30vt.home>
Date: Mon, 15 Jul 2013 15:51:06 -0600
From: Alex Williamson <alex.williamson@...hat.com>
To: Vijay Mohan Pandarathil <vijaymohan.pandarathil@...com>
Cc: gleb@...hat.com, bhelgaas@...gle.com, blauwirbel@...il.com,
lance.oritz@...com, kvm@...r.kernel.org, qemu-devel@...gnu.org,
linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [Qemu-devel] [PATCH] QEMU-AER: Qemu changes to support AER for
VFIO-PCI devices
On Sun, 2013-07-14 at 01:48 -0600, Vijay Mohan Pandarathil wrote:
> Add support for error containment when a VFIO device assigned to a KVM
> guest encounters an error. This is for PCIe devices/drivers that support AER
> functionality. When the host OS is notified of an error in a device either
> through the firmware first approach or through an interrupt handled by the AER
> root port driver, the error handler registered by the vfio-pci driver gets
> invoked. The qemu process is signaled through an eventfd registered per
> VFIO device by the qemu process. In the eventfd handler, qemu decides on
> what action to take. In this implementation, guest is brought down to
> contain the error.
>
> The kernel patches for the above functionality has been already accepted.
>
> This is a refresh of the QEMU patch which was reviewed earlier.
> http://marc.info/?l=linux-kernel&m=136281557608087&w=2
> This patch has the same contents and has been built after refreshing
> to latest upstream and after the linux headers have been updated in qemu.
>
> - 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@...com>
> ---
> hw/misc/vfio.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 123 insertions(+)
Applied. Thanks,
Alex
> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
> index 540c377..414c999 100644
> --- a/hw/misc/vfio.c
> +++ b/hw/misc/vfio.c
> @@ -158,6 +158,7 @@ typedef struct VFIODevice {
> PCIHostDeviceAddress host;
> QLIST_ENTRY(VFIODevice) next;
> struct VFIOGroup *group;
> + EventNotifier err_notifier;
> uint32_t features;
> #define VFIO_FEATURE_ENABLE_VGA_BIT 0
> #define VFIO_FEATURE_ENABLE_VGA (1 << VFIO_FEATURE_ENABLE_VGA_BIT)
> @@ -165,6 +166,7 @@ typedef struct VFIODevice {
> uint8_t pm_cap;
> bool reset_works;
> bool has_vga;
> + bool pci_aer;
> } VFIODevice;
>
> typedef struct VFIOGroup {
> @@ -2781,6 +2783,7 @@ 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);
> @@ -2924,6 +2927,18 @@ static int vfio_get_device(VFIOGroup *group, const char *name, VFIODevice *vdev)
>
> vdev->has_vga = true;
> }
> + 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) {
> @@ -2946,6 +2961,112 @@ 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);
> @@ -3078,6 +3199,7 @@ static int vfio_initfn(PCIDevice *pdev)
> }
>
> add_boot_device_path(vdev->bootindex, &pdev->qdev, NULL);
> + vfio_register_err_notifier(vdev);
>
> return 0;
>
> @@ -3097,6 +3219,7 @@ 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) {
--
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