Re: [PATCH v3 1/3] virtio-pci: add handling of PCI ATS and Device-TLB enable/disable

[Jason Wang]

On Fri, May 12, 2023 at 9:51 PM Viktor Prutyanov <viktor@daynix.com> wrote:
>
> According to PCIe Address Translation Services specification 5.1.3.,
> ATS Control Register has Enable bit to enable/disable ATS. Guest may
> enable/disable PCI ATS and, accordingly, Device-TLB for the VirtIO PCI
> device. So, raise/lower a flag and call a trigger function to pass this
> event to a device implementation.
>
> Signed-off-by: Viktor Prutyanov <viktor@daynix.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

> ---
>  hw/virtio/virtio-pci.c     | 36 ++++++++++++++++++++++++++++++++++++
>  include/hw/virtio/virtio.h |  2 ++
>  2 files changed, 38 insertions(+)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 02fb84a8fa..edbc0daa18 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -716,6 +716,38 @@ virtio_address_space_read(VirtIOPCIProxy *proxy, hwaddr 
> addr,
>      }
>  }
>
> +static void virtio_pci_ats_ctrl_trigger(PCIDevice *pci_dev, bool enable)
> +{
> +    VirtIOPCIProxy *proxy = VIRTIO_PCI(pci_dev);
> +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> +
> +    vdev->device_iotlb_enabled = enable;
> +
> +    if (k->toggle_device_iotlb) {
> +        k->toggle_device_iotlb(vdev);
> +    }
> +}
> +
> +static void pcie_ats_config_write(PCIDevice *dev, uint32_t address,
> +                                  uint32_t val, int len)
> +{
> +    uint32_t off;
> +    uint16_t ats_cap = dev->exp.ats_cap;
> +
> +    if (!ats_cap || address < ats_cap) {
> +        return;
> +    }
> +    off = address - ats_cap;
> +    if (off >= PCI_EXT_CAP_ATS_SIZEOF) {
> +        return;
> +    }
> +
> +    if (range_covers_byte(off, len, PCI_ATS_CTRL + 1)) {
> +        virtio_pci_ats_ctrl_trigger(dev, !!(val & PCI_ATS_CTRL_ENABLE));
> +    }
> +}
> +
>  static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
>                                  uint32_t val, int len)
>  {
> @@ -729,6 +761,10 @@ static void virtio_write_config(PCIDevice *pci_dev, 
> uint32_t address,
>          pcie_cap_flr_write_config(pci_dev, address, val, len);
>      }
>
> +    if (proxy->flags & VIRTIO_PCI_FLAG_ATS) {
> +        pcie_ats_config_write(pci_dev, address, val, len);
> +    }
> +
>      if (range_covers_byte(address, len, PCI_COMMAND)) {
>          if (!(pci_dev->config[PCI_COMMAND] & PCI_COMMAND_MASTER)) {
>              virtio_set_disabled(vdev, true);
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index f6b38f7e9c..af86ed7249 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -155,6 +155,7 @@ struct VirtIODevice
>      QLIST_HEAD(, VirtQueue) *vector_queues;
>      QTAILQ_ENTRY(VirtIODevice) next;
>      EventNotifier config_notifier;
> +    bool device_iotlb_enabled;
>  };
>
>  struct VirtioDeviceClass {
> @@ -212,6 +213,7 @@ struct VirtioDeviceClass {
>      const VMStateDescription *vmsd;
>      bool (*primary_unplug_pending)(void *opaque);
>      struct vhost_dev *(*get_vhost)(VirtIODevice *vdev);
> +    void (*toggle_device_iotlb)(VirtIODevice *vdev);
>  };
>
>  void virtio_instance_init_common(Object *proxy_obj, void *data,
> --
> 2.35.1
>