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

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Jan 10, 2022 at 06:27:05AM +0000, Longpeng (Mike, Cloud Infrastructure Service Product Dept.) wrote:
> 
> 
> > -----Original Message-----
> > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > Sent: Monday, January 10, 2022 1:43 PM
> > To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> > <longpeng2@huawei.com>
> > Cc: stefanha@redhat.com; jasowang@redhat.com; sgarzare@redhat.com;
> > cohuck@redhat.com; pbonzini@redhat.com; Gonglei (Arei)
> > <arei.gonglei@huawei.com>; Yechuan <yechuan@huawei.com>; Huangzhichao
> > <huangzhichao@huawei.com>; qemu-devel@nongnu.org
> > Subject: Re: [RFC 01/10] virtio: get class_id and pci device id by the virtio
> > id
> > 
> > On Wed, Jan 05, 2022 at 08:58:51AM +0800, Longpeng(Mike) 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".
> > 
> > ton of typos here.
> > 
> 
> Will fix all in the V2.
> 
> > > 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;
> > 
> > 
> > if this is transitional as comment says make it explicit
> > in the names and comments.
> > 
> 
> OK.
> 
> > > +
> > > +static const VirtIOPCIIDInfo virtio_pci_id_info[] = {
> > > +    {
> > > +        .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,
> > > +    },
> > > +};
> > > +
> > 
> > 
> > this is the list from the spec:
> > 
> > 
> > So this is the list from the spec:
> > 
> > 0x1000 network card
> > 0x1001 block device
> > 0x1002 memory ballooning (traditional)
> > 0x1003 console
> > 0x1004 SCSI host
> > 0x1005 entropy source
> > 0x1009 9P transport
> > 
> 
> Why the following device IDs are introduced? They are non
> transitional devices.
> 
> #define PCI_DEVICE_ID_VIRTIO_VSOCK       0x1012
> #define PCI_DEVICE_ID_VIRTIO_PMEM        0x1013
> #define PCI_DEVICE_ID_VIRTIO_IOMMU       0x1014
> #define PCI_DEVICE_ID_VIRTIO_MEM         0x1015

Just a single place to put these things.
E.g. vsock id is used in more than 1 place.

> > 
> > I'd drop all the rest, use the algorithm for non transitional.
> > And when class is other I'd just not include it in the array,
> > make this the default.
> > 
> > 
> > 
> > > +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