Re: [PATCH v6 09/21] vfio/iommufd: Enable pci hot reset through iommufd cdev interface

[Eric Auger <eric.auger@redhat.com>]

On 11/14/23 11:09, Zhenzhong Duan wrote:
> Add a new callback iommufd_cdev_pci_hot_reset to do iommufd specific
> check and reset operation.

nit: Implement the newly introduced pci_hot_reset callback?
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
> v6: pci_hot_reset return -errno if fails
>
>  hw/vfio/iommufd.c    | 145 +++++++++++++++++++++++++++++++++++++++++++
>  hw/vfio/trace-events |   1 +
>  2 files changed, 146 insertions(+)
>
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index e5bf528e89..3eec428162 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -24,6 +24,7 @@
>  #include "sysemu/reset.h"
>  #include "qemu/cutils.h"
>  #include "qemu/chardev_open.h"
> +#include "pci.h"
>  
>  static int iommufd_cdev_map(VFIOContainerBase *bcontainer, hwaddr iova,
>                              ram_addr_t size, void *vaddr, bool readonly)
> @@ -473,9 +474,153 @@ static void iommufd_cdev_detach(VFIODevice *vbasedev)
>      close(vbasedev->fd);
>  }
>  
> +static VFIODevice *iommufd_cdev_pci_find_by_devid(__u32 devid)
> +{
> +    VFIODevice *vbasedev_iter;
> +
> +    QLIST_FOREACH(vbasedev_iter, &vfio_device_list, global_next) {
> +        if (vbasedev_iter->bcontainer->ops != &vfio_iommufd_ops) {
> +            continue;
> +        }
> +        if (devid == vbasedev_iter->devid) {
> +            return vbasedev_iter;
> +        }
> +    }
> +    return NULL;
> +}
> +
> +static int iommufd_cdev_pci_hot_reset(VFIODevice *vbasedev, bool single)
> +{
> +    VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
> +    struct vfio_pci_hot_reset_info *info = NULL;
> +    struct vfio_pci_dependent_device *devices;
> +    struct vfio_pci_hot_reset *reset;
> +    int ret, i;
> +    bool multi = false;
> +
> +    trace_vfio_pci_hot_reset(vdev->vbasedev.name, single ? "one" : "multi");
> +
> +    if (!single) {
> +        vfio_pci_pre_reset(vdev);
> +    }
> +    vdev->vbasedev.needs_reset = false;
> +
> +    ret = vfio_pci_get_pci_hot_reset_info(vdev, &info);
> +
> +    if (ret) {
> +        goto out_single;
> +    }
> +
> +    assert(info->flags & VFIO_PCI_HOT_RESET_FLAG_DEV_ID);
> +
> +    devices = &info->devices[0];
> +
> +    if (!(info->flags & VFIO_PCI_HOT_RESET_FLAG_DEV_ID_OWNED)) {
> +        if (!vdev->has_pm_reset) {
> +            for (i = 0; i < info->count; i++) {
> +                if (devices[i].devid == VFIO_PCI_DEVID_NOT_OWNED) {
> +                    error_report("vfio: Cannot reset device %s, "
> +                                 "depends on device %04x:%02x:%02x.%x "
> +                                 "which is not owned.",
> +                                 vdev->vbasedev.name, devices[i].segment,
> +                                 devices[i].bus, PCI_SLOT(devices[i].devfn),
> +                                 PCI_FUNC(devices[i].devfn));
> +                }
> +            }
> +        }
> +        ret = -EPERM;
> +        goto out_single;
> +    }
> +
> +    trace_vfio_pci_hot_reset_has_dep_devices(vdev->vbasedev.name);
> +
> +    for (i = 0; i < info->count; i++) {
> +        VFIOPCIDevice *tmp;
> +        VFIODevice *vbasedev_iter;
> +
> +        trace_iommufd_cdev_pci_hot_reset_dep_devices(devices[i].segment,
> +                                                     devices[i].bus,
> +                                                     PCI_SLOT(devices[i].devfn),
> +                                                     PCI_FUNC(devices[i].devfn),
> +                                                     devices[i].devid);
> +
> +        /*
> +         * If a VFIO cdev device is resettable, all the dependent devices
> +         * are either bound to same iommufd or within same iommu_groups as
> +         * one of the iommufd bound devices.
> +         */
> +        assert(devices[i].devid != VFIO_PCI_DEVID_NOT_OWNED);
> +
> +        if (devices[i].devid == vdev->vbasedev.devid ||
> +            devices[i].devid == VFIO_PCI_DEVID_OWNED) {
> +            continue;
> +        }
> +
> +        vbasedev_iter = iommufd_cdev_pci_find_by_devid(devices[i].devid);
> +        if (!vbasedev_iter || !vbasedev_iter->dev->realized ||
> +            vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
> +            continue;
> +        }
> +        tmp = container_of(vbasedev_iter, VFIOPCIDevice, vbasedev);
> +        if (single) {
> +            ret = -EINVAL;
> +            goto out_single;
> +        }
> +        vfio_pci_pre_reset(tmp);
> +        tmp->vbasedev.needs_reset = false;
> +        multi = true;
> +    }
> +
> +    if (!single && !multi) {
> +        ret = -EINVAL;
> +        goto out_single;
> +    }
> +
> +    /* Use zero length array for hot reset with iommufd backend */
> +    reset = g_malloc0(sizeof(*reset));
> +    reset->argsz = sizeof(*reset);
> +
> +     /* Bus reset! */
> +    ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_PCI_HOT_RESET, reset);
> +    g_free(reset);
> +    if (ret) {
> +        ret = -errno;
> +    }
> +
> +    trace_vfio_pci_hot_reset_result(vdev->vbasedev.name,
> +                                    ret ? strerror(errno) : "Success");
> +
> +    /* Re-enable INTx on affected devices */
> +    for (i = 0; i < info->count; i++) {
> +        VFIOPCIDevice *tmp;
> +        VFIODevice *vbasedev_iter;
> +
> +        if (devices[i].devid == vdev->vbasedev.devid ||
> +            devices[i].devid == VFIO_PCI_DEVID_OWNED) {
> +            continue;
> +        }
> +
> +        vbasedev_iter = iommufd_cdev_pci_find_by_devid(devices[i].devid);
> +        if (!vbasedev_iter || !vbasedev_iter->dev->realized ||
> +            vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
> +            continue;
> +        }
> +        tmp = container_of(vbasedev_iter, VFIOPCIDevice, vbasedev);
nit: I see this block of code also is used above for the pre_reset. May
be interesting to introduce an helper? Could be done later though
> +        vfio_pci_post_reset(tmp);
> +    }
> +out_single:
> +    if (!single) {
> +        vfio_pci_post_reset(vdev);
> +    }
> +    g_free(info);
> +
> +    return ret;
> +}
> +
>  const VFIOIOMMUOps vfio_iommufd_ops = {
>      .dma_map = iommufd_cdev_map,
>      .dma_unmap = iommufd_cdev_unmap,
>      .attach_device = iommufd_cdev_attach,
>      .detach_device = iommufd_cdev_detach,
> +    .pci_hot_reset = iommufd_cdev_pci_hot_reset,
>  };
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index 5d3e9e8cee..d838232d5a 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -174,3 +174,4 @@ iommufd_cdev_detach_ioas_hwpt(int iommufd, const char *name, const char *str, in
>  iommufd_cdev_fail_attach_existing_container(const char *msg) " %s"
>  iommufd_cdev_alloc_ioas(int iommufd, int ioas_id) " [iommufd=%d] new IOMMUFD container with ioasid=%d"
>  iommufd_cdev_device_info(char *name, int devfd, int num_irqs, int num_regions, int flags) " %s (%d) num_irqs=%d num_regions=%d flags=%d"
> +iommufd_cdev_pci_hot_reset_dep_devices(int domain, int bus, int slot, int function, int dev_id) "\t%04x:%02x:%02x.%x devid %d"
Otherwise looks good to me.

Reviewed-by: Eric Auger <eric.auger@redhat.com>


Eric