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Message-ID: <1357754873.3224.777.camel@bling.home>
Date: Wed, 09 Jan 2013 11:07:53 -0700
From: Alex Williamson <alex.williamson@...hat.com>
To: "Pandarathil, Vijaymohan R" <vijaymohan.pandarathil@...com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
Gleb Natapov <gleb@...hat.com>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"qemu-devel@...gnu.org" <qemu-devel@...gnu.org>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] QEMU-AER: Qemu changes to support AER for VFIO-PCI
devices
On Wed, 2013-01-09 at 06:26 +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 a new ioctl
>
> - When the device encounters an error, the eventfd is signaled
> 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@...com>
> ---
> hw/vfio_pci.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++
> linux-headers/linux/vfio.h | 9 ++++++++
> 2 files changed, 65 insertions(+)
>
> diff --git a/hw/vfio_pci.c b/hw/vfio_pci.c
> index 28c8303..9c3c28b 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
> @@ -130,6 +131,8 @@ typedef struct VFIODevice {
> QLIST_ENTRY(VFIODevice) next;
> struct VFIOGroup *group;
> bool reset_works;
> + EventNotifier errfd;
Misleading name, it's an EventNotifier not an fd.
> + __u32 dev_info_flags;
> } VFIODevice;
>
> typedef struct VFIOGroup {
> @@ -1805,6 +1808,8 @@ static int vfio_get_device(VFIOGroup *group, const char *name, VFIODevice *vdev)
> DPRINTF("Device %s flags: %u, regions: %u, irgs: %u\n", name,
> dev_info.flags, dev_info.num_regions, dev_info.num_irqs);
>
> + vdev->dev_info_flags = dev_info.flags;
> +
We test the VFIO_DEVICE_FLAGS_RESET elsewhere by caching the bit into a
variable, why not do that here too?
> if (!(dev_info.flags & VFIO_DEVICE_FLAGS_PCI)) {
> error_report("vfio: Um, this isn't a PCI device\n");
> goto error;
> @@ -1900,6 +1905,55 @@ static void vfio_put_device(VFIODevice *vdev)
> }
> }
>
> +static void vfio_errfd_handler(void *opaque)
> +{
> + VFIODevice *vdev = opaque;
> +
> + if (!event_notifier_test_and_clear(&vdev->errfd)) {
> + 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
> + * 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);
> +
> + qemu_system_shutdown_request();
I would have figured hw_error
> + return;
> +}
> +
> +static void vfio_register_errfd(VFIODevice *vdev)
> +{
> + int32_t pfd;
"pfd" is used elsewhere in vfio as "Pointer to FD", this is just a fd.
> + int ret;
> +
> + if (!(vdev->dev_info_flags & VFIO_DEVICE_FLAGS_AER_NOTIFY)) {
> + error_report("vfio: Warning: Error notification not supported for the device\n");
This should probably just be a debug print.
> + return;
> + }
> + if (event_notifier_init(&vdev->errfd, 0)) {
> + error_report("vfio: Warning: Unable to init event notifier for error detection\n");
> + return;
> + }
> + pfd = event_notifier_get_fd(&vdev->errfd);
> + qemu_set_fd_handler(pfd, vfio_errfd_handler, NULL, vdev);
> +
> + ret = ioctl(vdev->fd, VFIO_DEVICE_SET_ERRFD, pfd);
> + if (ret) {
> + error_report("vfio: Warning: Failed to setup error fd: %d\n", ret);
> + qemu_set_fd_handler(pfd, NULL, NULL, vdev);
> + event_notifier_cleanup(&vdev->errfd);
> + }
> + return;
> +}
> static int vfio_initfn(PCIDevice *pdev)
> {
> VFIODevice *pvdev, *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> @@ -2010,6 +2064,8 @@ static int vfio_initfn(PCIDevice *pdev)
> }
> }
>
> + vfio_register_errfd(vdev);
> +
No cleanup in exitfn?! Thanks,
Alex
> return 0;
>
> out_teardown:
> diff --git a/linux-headers/linux/vfio.h b/linux-headers/linux/vfio.h
> index 4758d1b..0ca4eeb 100644
> --- a/linux-headers/linux/vfio.h
> +++ b/linux-headers/linux/vfio.h
> @@ -147,6 +147,7 @@ struct vfio_device_info {
> __u32 flags;
> #define VFIO_DEVICE_FLAGS_RESET (1 << 0) /* Device supports reset */
> #define VFIO_DEVICE_FLAGS_PCI (1 << 1) /* vfio-pci device */
> +#define VFIO_DEVICE_FLAGS_AER_NOTIFY (1 << 2) /* Supports aer notification */
> __u32 num_regions; /* Max region index + 1 */
> __u32 num_irqs; /* Max IRQ index + 1 */
> };
> @@ -288,6 +289,14 @@ struct vfio_irq_set {
> */
> #define VFIO_DEVICE_RESET _IO(VFIO_TYPE, VFIO_BASE + 11)
>
> +/**
> + * VFIO_DEVICE_SET_ERRFD - _IO(VFIO_TYPE, VFIO_BASE + 12)
> + *
> + * Pass the eventfd to the vfio-pci driver for signalling any device
> + * error notifications
> + */
> +#define VFIO_DEVICE_SET_ERRFD _IO(VFIO_TYPE, VFIO_BASE + 12)
> +
> /*
> * The VFIO-PCI bus driver makes use of the following fixed region and
> * IRQ index mapping. Unimplemented regions return a size of zero.
--
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