Re: [Qemu-devel] [RfC PATCH 01/15] virtio-pci: add flags to enable/disable legacy/modern

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

On Mon, Feb 23, 2015 at 11:23:17AM +0100, Gerd Hoffmann wrote:
> Add VIRTIO_PCI_FLAG_DISABLE_LEGACY and VIRTIO_PCI_FLAG_DISABLE_MODERN
> for VirtIOPCIProxy->flags.  Also add properties for them.  They can be
> used to disable modern (virtio 1.0) or legacy (virtio 0.9) modes.  By
> default both are advertized and the guest driver can choose.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

I merged patches 1 and 2. I'm guessing you don't want gpu merged yet?

> ---
>  hw/virtio/virtio-pci.c | 46 +++++++++++++++++++++++++++++++++-------------
>  hw/virtio/virtio-pci.h |  6 ++++++
>  2 files changed, 39 insertions(+), 13 deletions(-)
> 
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 4c9a0b8..6c0c650 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -1233,6 +1233,8 @@ static void virtio_pci_device_plugged(DeviceState *d)
>  {
>      VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
>      VirtioBusState *bus = &proxy->bus;
> +    bool legacy = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_LEGACY);
> +    bool modern = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN);
>      uint8_t *config;
>      uint32_t size;
>  
> @@ -1240,13 +1242,24 @@ static void virtio_pci_device_plugged(DeviceState *d)
>      if (proxy->class_code) {
>          pci_config_set_class(config, proxy->class_code);
>      }
> -    pci_set_word(config + PCI_SUBSYSTEM_VENDOR_ID,
> -                 pci_get_word(config + PCI_VENDOR_ID));
> -    pci_set_word(config + PCI_SUBSYSTEM_ID, virtio_bus_get_vdev_id(bus));
> +
> +    if (legacy) {
> +        /* legacy and transitional */
> +        pci_set_word(config + PCI_SUBSYSTEM_VENDOR_ID,
> +                     pci_get_word(config + PCI_VENDOR_ID));
> +        pci_set_word(config + PCI_SUBSYSTEM_ID, virtio_bus_get_vdev_id(bus));
> +    } else {
> +        /* pure virtio-1.0 */
> +        pci_set_word(config + PCI_VENDOR_ID,
> +                     PCI_VENDOR_ID_REDHAT_QUMRANET);
> +        pci_set_word(config + PCI_DEVICE_ID,
> +                     0x1040 + virtio_bus_get_vdev_id(bus));
> +        pci_config_set_revision(config, 1);
> +    }
>      config[PCI_INTERRUPT_PIN] = 1;
>  
>  
> -    if (1) { /* TODO: Make this optional, dependent on virtio 1.0 */
> +    if (modern) {
>          struct virtio_pci_cap common = {
>              .cfg_type = VIRTIO_PCI_CAP_COMMON_CFG,
>              .cap_len = sizeof common,
> @@ -1359,17 +1372,20 @@ static void virtio_pci_device_plugged(DeviceState *d)
>  
>      proxy->pci_dev.config_write = virtio_write_config;
>  
> -    size = VIRTIO_PCI_REGION_SIZE(&proxy->pci_dev)
> -         + virtio_bus_get_vdev_config_len(bus);
> -    if (size & (size - 1)) {
> -        size = 1 << qemu_fls(size);
> -    }
> +    if (legacy) {
> +        size = VIRTIO_PCI_REGION_SIZE(&proxy->pci_dev)
> +            + virtio_bus_get_vdev_config_len(bus);
> +        if (size & (size - 1)) {
> +            size = 1 << qemu_fls(size);
> +        }
>  
> -    memory_region_init_io(&proxy->bar, OBJECT(proxy), &virtio_pci_config_ops,
> -                          proxy, "virtio-pci", size);
> +        memory_region_init_io(&proxy->bar, OBJECT(proxy),
> +                              &virtio_pci_config_ops,
> +                              proxy, "virtio-pci", size);
>  
> -    pci_register_bar(&proxy->pci_dev, 0, PCI_BASE_ADDRESS_SPACE_IO,
> -                     &proxy->bar);
> +        pci_register_bar(&proxy->pci_dev, 0, PCI_BASE_ADDRESS_SPACE_IO,
> +                         &proxy->bar);
> +    }
>  
>      if (!kvm_has_many_ioeventfds()) {
>          proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;
> @@ -1416,6 +1432,10 @@ static void virtio_pci_reset(DeviceState *qdev)
>  static Property virtio_pci_properties[] = {
>      DEFINE_PROP_BIT("virtio-pci-bus-master-bug-migration", VirtIOPCIProxy, flags,
>                      VIRTIO_PCI_FLAG_BUS_MASTER_BUG_MIGRATION_BIT, false),
> +    DEFINE_PROP_BIT("disable-legacy", VirtIOPCIProxy, flags,
> +                    VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT, false),
> +    DEFINE_PROP_BIT("disable-modern", VirtIOPCIProxy, flags,
> +                    VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT, false),
>      DEFINE_VIRTIO_COMMON_FEATURES(VirtIOPCIProxy, host_features),
>      DEFINE_PROP_END_OF_LIST(),
>  };
> diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
> index 2cddd6a..3068a63 100644
> --- a/hw/virtio/virtio-pci.h
> +++ b/hw/virtio/virtio-pci.h
> @@ -63,6 +63,12 @@ typedef struct VirtioBusClass VirtioPCIBusClass;
>  #define VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT 1
>  #define VIRTIO_PCI_FLAG_USE_IOEVENTFD   (1 << VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT)
>  
> +/* virtio version flags */
> +#define VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT 2
> +#define VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT 3
> +#define VIRTIO_PCI_FLAG_DISABLE_LEGACY (1 << VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT)
> +#define VIRTIO_PCI_FLAG_DISABLE_MODERN (1 << VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT)
> +
>  typedef struct {
>      MSIMessage msg;
>      int virq;
> -- 
> 1.8.3.1