RE: [RFC 01/10] virtio: get class_id and pci device id by the virtio id

[Longpeng (Mike, Cloud Infrastructure Service Product Dept.)]

> -----Original Message-----
> From: Jason Wang [mailto:jasowang@redhat.com]
> Sent: Wednesday, January 5, 2022 12:38 PM
> To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> <longpeng2@huawei.com>
> Cc: Stefan Hajnoczi <stefanha@redhat.com>; mst <mst@redhat.com>; Stefano
> Garzarella <sgarzare@redhat.com>; Cornelia Huck <cohuck@redhat.com>; pbonzini
> <pbonzini@redhat.com>; Gonglei (Arei) <arei.gonglei@huawei.com>; Yechuan
> <yechuan@huawei.com>; Huangzhichao <huangzhichao@huawei.com>; qemu-devel
> <qemu-devel@nongnu.org>
> Subject: Re: [RFC 01/10] virtio: get class_id and pci device id by the virtio
> id
> 
> On Wed, Jan 5, 2022 at 8:59 AM Longpeng(Mike) <longpeng2@huawei.com> wrote:
> >
> > From: Longpeng <longpeng2@huawei.com>
> >
> > Add helpers to get the "Transitional PCI Device ID" and "class_id" of the
> > deivce which is specificed by the "Virtio Device ID".
> >
> > These helpers will be used to build the generic vDPA device later.
> >
> > Signed-off-by: Longpeng <longpeng2@huawei.com>
> > ---
> >  hw/virtio/virtio-pci.c | 93 ++++++++++++++++++++++++++++++++++++++++++
> >  hw/virtio/virtio-pci.h |  4 ++
> >  2 files changed, 97 insertions(+)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index 750aa47ec1..843085c4ea 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -19,6 +19,7 @@
> >
> >  #include "exec/memop.h"
> >  #include "standard-headers/linux/virtio_pci.h"
> > +#include "standard-headers/linux/virtio_ids.h"
> >  #include "hw/boards.h"
> >  #include "hw/virtio/virtio.h"
> >  #include "migration/qemu-file-types.h"
> > @@ -213,6 +214,95 @@ static int virtio_pci_load_queue(DeviceState *d, int n,
> QEMUFile *f)
> >      return 0;
> >  }
> >
> > +typedef struct VirtIOPCIIDInfo {
> > +    uint16_t vdev_id; /* virtio id */
> > +    uint16_t pdev_id; /* pci device id */
> > +    uint16_t class_id;
> > +} VirtIOPCIIDInfo;
> > +
> > +static const VirtIOPCIIDInfo virtio_pci_id_info[] = {
> > +    {
> 
> Any way to get rid of this array? E.g using the algorithm that is used
> by the kernel virtio driver.
> 

For device id, we can use the algorithm if we no need to support
Transitional id. But how to get the class id ?

> Thanks
> 
> > +        .vdev_id = VIRTIO_ID_NET,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_NET,
> > +        .class_id = PCI_CLASS_NETWORK_ETHERNET,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_BLOCK,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_BLOCK,
> > +        .class_id = PCI_CLASS_STORAGE_SCSI,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_CONSOLE,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_CONSOLE,
> > +        .class_id = PCI_CLASS_COMMUNICATION_OTHER,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_SCSI,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_SCSI,
> > +        .class_id = PCI_CLASS_STORAGE_SCSI,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_9P,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_9P,
> > +        .class_id = PCI_BASE_CLASS_NETWORK,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_VSOCK,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_VSOCK,
> > +        .class_id = PCI_CLASS_COMMUNICATION_OTHER,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_IOMMU,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_IOMMU,
> > +        .class_id = PCI_CLASS_OTHERS,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_MEM,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_MEM,
> > +        .class_id = PCI_CLASS_OTHERS,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_PMEM,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_PMEM,
> > +        .class_id = PCI_CLASS_OTHERS,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_RNG,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_RNG,
> > +        .class_id = PCI_CLASS_OTHERS,
> > +    },
> > +    {
> > +        .vdev_id = VIRTIO_ID_BALLOON,
> > +        .pdev_id = PCI_DEVICE_ID_VIRTIO_BALLOON,
> > +        .class_id = PCI_CLASS_OTHERS,
> > +    },
> > +};
> > +
> > +static VirtIOPCIIDInfo virtio_pci_get_id_info(uint16_t vdev_id)
> > +{
> > +    VirtIOPCIIDInfo info = {};
> > +    int i;
> > +
> > +    for (i = 0; i < ARRAY_SIZE(virtio_pci_id_info); i++) {
> > +        if (virtio_pci_id_info[i].vdev_id == vdev_id) {
> > +            info = virtio_pci_id_info[i];
> > +            break;
> > +        }
> > +    }
> > +
> > +    return info;
> > +}
> > +
> > +uint16_t virtio_pci_get_pci_devid(uint16_t device_id)
> > +{
> > +    return virtio_pci_get_id_info(device_id).pdev_id;
> > +}
> > +
> > +uint16_t virtio_pci_get_class_id(uint16_t device_id)
> > +{
> > +    return virtio_pci_get_id_info(device_id).class_id;
> > +}
> > +
> >  static bool virtio_pci_ioeventfd_enabled(DeviceState *d)
> >  {
> >      VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
> > @@ -1674,6 +1764,9 @@ static void virtio_pci_device_plugged(DeviceState *d,
> Error **errp)
> >           * is set to PCI_SUBVENDOR_ID_REDHAT_QUMRANET by default.
> >           */
> >          pci_set_word(config + PCI_SUBSYSTEM_ID,
> virtio_bus_get_vdev_id(bus));
> > +        if (proxy->pdev_id) {
> > +            pci_config_set_device_id(config, proxy->pdev_id);
> > +        }
> >      } else {
> >          /* pure virtio-1.0 */
> >          pci_set_word(config + PCI_VENDOR_ID,
> > diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
> > index 2446dcd9ae..06aa59436e 100644
> > --- a/hw/virtio/virtio-pci.h
> > +++ b/hw/virtio/virtio-pci.h
> > @@ -146,6 +146,7 @@ struct VirtIOPCIProxy {
> >      bool disable_modern;
> >      bool ignore_backend_features;
> >      OnOffAuto disable_legacy;
> > +    uint16_t pdev_id;
> >      uint32_t class_code;
> >      uint32_t nvectors;
> >      uint32_t dfselect;
> > @@ -158,6 +159,9 @@ struct VirtIOPCIProxy {
> >      VirtioBusState bus;
> >  };
> >
> > +uint16_t virtio_pci_get_pci_devid(uint16_t device_id);
> > +uint16_t virtio_pci_get_class_id(uint16_t device_id);
> > +
> >  static inline bool virtio_pci_modern(VirtIOPCIProxy *proxy)
> >  {
> >      return !proxy->disable_modern;
> > --
> > 2.23.0
> >