Re: [Qemu-devel] [RFC v1 05/18] vfio/pci: add pasid alloc/free implementation

[David Gibson]

On Fri, Jul 05, 2019 at 07:01:38PM +0800, Liu Yi L wrote:
> This patch adds vfio implementation PCIPASIDOps.alloc_pasid/free_pasid().
> These two functions are used to propagate guest pasid allocation and
> free requests to host via vfio container ioctl.

As I said in an earlier comment, I think doing this on the device is
conceptually incorrect.  I think we need an explcit notion of an SVM
context (i.e. the namespace in which all the PASIDs live) - which will
IIUC usually be shared amongst multiple devices.  The create and free
PASID requests should be on that object.

> 
> Cc: Kevin Tian <address@hidden>
> Cc: Jacob Pan <address@hidden>
> Cc: Peter Xu <address@hidden>
> Cc: Eric Auger <address@hidden>
> Cc: Yi Sun <address@hidden>
> Cc: David Gibson <address@hidden>
> Signed-off-by: Liu Yi L <address@hidden>
> Signed-off-by: Yi Sun <address@hidden>
> ---
>  hw/vfio/pci.c | 61 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index ce3fe96..ab184ad 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2690,6 +2690,65 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice 
> *vdev)
>      vdev->req_enabled = false;
>  }
>  
> +static int vfio_pci_device_request_pasid_alloc(PCIBus *bus,
> +                                               int32_t devfn,
> +                                               uint32_t min_pasid,
> +                                               uint32_t max_pasid)
> +{
> +    PCIDevice *pdev = bus->devices[devfn];
> +    VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> +    VFIOContainer *container = vdev->vbasedev.group->container;
> +    struct vfio_iommu_type1_pasid_request req;
> +    unsigned long argsz;
> +    int pasid;
> +
> +    argsz = sizeof(req);
> +    req.argsz = argsz;
> +    req.flag = VFIO_IOMMU_PASID_ALLOC;
> +    req.min_pasid = min_pasid;
> +    req.max_pasid = max_pasid;
> +
> +    rcu_read_lock();
> +    pasid = ioctl(container->fd, VFIO_IOMMU_PASID_REQUEST, &req);
> +    if (pasid < 0) {
> +        error_report("vfio_pci_device_request_pasid_alloc:"
> +                     " request failed, contanier: %p", container);
> +    }
> +    rcu_read_unlock();
> +    return pasid;
> +}
> +
> +static int vfio_pci_device_request_pasid_free(PCIBus *bus,
> +                                              int32_t devfn,
> +                                              uint32_t pasid)
> +{
> +    PCIDevice *pdev = bus->devices[devfn];
> +    VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> +    VFIOContainer *container = vdev->vbasedev.group->container;
> +    struct vfio_iommu_type1_pasid_request req;
> +    unsigned long argsz;
> +    int ret = 0;
> +
> +    argsz = sizeof(req);
> +    req.argsz = argsz;
> +    req.flag = VFIO_IOMMU_PASID_FREE;
> +    req.pasid = pasid;
> +
> +    rcu_read_lock();
> +    ret = ioctl(container->fd, VFIO_IOMMU_PASID_REQUEST, &req);
> +    if (ret != 0) {
> +        error_report("vfio_pci_device_request_pasid_free:"
> +                     " request failed, contanier: %p", container);
> +    }
> +    rcu_read_unlock();
> +    return ret;
> +}
> +
> +static PCIPASIDOps vfio_pci_pasid_ops = {
> +    .alloc_pasid = vfio_pci_device_request_pasid_alloc,
> +    .free_pasid = vfio_pci_device_request_pasid_free,
> +};
> +
>  static void vfio_realize(PCIDevice *pdev, Error **errp)
>  {
>      VFIOPCIDevice *vdev = PCI_VFIO(pdev);
> @@ -2991,6 +3050,8 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>      vfio_register_req_notifier(vdev);
>      vfio_setup_resetfn_quirk(vdev);
>  
> +    pci_setup_pasid_ops(pdev, &vfio_pci_pasid_ops);
> +
>      return;
>  
>  out_teardown:

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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