Re: [Qemu-devel] [PATCH v3 04/17] virtio: use standard-headers

[Thomas Huth]

On Mon, 16 Feb 2015 22:35:46 +0100
"Michael S. Tsirkin" <address@hidden> wrote:

> Drop a bunch of code duplicated from virtio_config.h and virtio_ring.h.
> This makes us rename event index accessors which conflict,
> as reusing the ones from virtio_ring.h isn't trivial.
> 
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>  hw/9pfs/virtio-9p.h        |  1 +
>  include/hw/virtio/virtio.h | 48 
> ++--------------------------------------------
>  hw/virtio/virtio.c         | 23 +++++-----------------
>  3 files changed, 8 insertions(+), 64 deletions(-)
> 
> diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
> index 2c3603a..0776424 100644
> --- a/hw/9pfs/virtio-9p.h
> +++ b/hw/9pfs/virtio-9p.h
> @@ -8,6 +8,7 @@
>  #include <sys/resource.h>
>  #include <glib.h>
>  #include "hw/virtio/virtio.h"
> +#include "hw/virtio/virtio-9p.h"
>  #include "fsdev/file-op-9p.h"
>  #include "fsdev/virtio-9p-marshal.h"
>  #include "qemu/thread.h"
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index f24997d..d1b416b 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -19,56 +19,12 @@
>  #include "hw/qdev.h"
>  #include "sysemu/sysemu.h"
>  #include "qemu/event_notifier.h"
> -#ifdef CONFIG_VIRTFS
> -#include "hw/virtio/virtio-9p.h"
> -#endif
> +#include "standard-headers/linux/virtio_config.h"
> +#include "standard-headers/linux/virtio_ring.h"
> 
> -/* from Linux's linux/virtio_config.h */
> -
> -/* Status byte for guest to report progress, and synchronize features. */
> -/* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) 
> */
> -#define VIRTIO_CONFIG_S_ACKNOWLEDGE     1
> -/* We have found a driver for the device. */
> -#define VIRTIO_CONFIG_S_DRIVER          2
> -/* Driver has used its parts of the config, and is happy */
> -#define VIRTIO_CONFIG_S_DRIVER_OK       4
> -/* We've given up on this device. */
> -#define VIRTIO_CONFIG_S_FAILED          0x80
> -
> -/* Some virtio feature bits (currently bits 28 through 31) are reserved for 
> the
> - * transport being used (eg. virtio_ring), the rest are per-device feature 
> bits. */
> -#define VIRTIO_TRANSPORT_F_START        28
> -#define VIRTIO_TRANSPORT_F_END          32
> -
> -/* We notify when the ring is completely used, even if the guest is 
> suppressing
> - * callbacks */
> -#define VIRTIO_F_NOTIFY_ON_EMPTY        24
> -/* Can the device handle any descriptor layout? */
> -#define VIRTIO_F_ANY_LAYOUT             27
> -/* We support indirect buffer descriptors */
> -#define VIRTIO_RING_F_INDIRECT_DESC     28
> -/* The Guest publishes the used index for which it expects an interrupt
> - * at the end of the avail ring. Host should ignore the avail->flags field. 
> */
> -/* The Host publishes the avail index for which it expects a kick
> - * at the end of the used ring. Guest should ignore the used->flags field. */
> -#define VIRTIO_RING_F_EVENT_IDX         29
>  /* A guest should never accept this.  It implies negotiation is broken. */
>  #define VIRTIO_F_BAD_FEATURE         30
> 
> -/* from Linux's linux/virtio_ring.h */
> -
> -/* This marks a buffer as continuing via the next field. */
> -#define VRING_DESC_F_NEXT       1
> -/* This marks a buffer as write-only (otherwise read-only). */
> -#define VRING_DESC_F_WRITE      2
> -/* This means the buffer contains a list of buffer descriptors. */
> -#define VRING_DESC_F_INDIRECT  4
> -
> -/* This means don't notify other side when buffer added. */
> -#define VRING_USED_F_NO_NOTIFY  1
> -/* This means don't interrupt guest when buffer consumed. */
> -#define VRING_AVAIL_F_NO_INTERRUPT      1
> -
>  struct VirtQueue;
> 
>  static inline hwaddr vring_align(hwaddr addr,
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index d735343..f783f31 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -155,7 +155,7 @@ static inline uint16_t vring_avail_ring(VirtQueue *vq, 
> int i)
>      return virtio_lduw_phys(vq->vdev, pa);
>  }
> 
> -static inline uint16_t vring_used_event(VirtQueue *vq)
> +static inline uint16_t vring_get_used_event(VirtQueue *vq)
>  {
>      return vring_avail_ring(vq, vq->vring.num);
>  }
> @@ -204,7 +204,7 @@ static inline void vring_used_flags_unset_bit(VirtQueue 
> *vq, int mask)
>      virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) & ~mask);
>  }
> 
> -static inline void vring_avail_event(VirtQueue *vq, uint16_t val)
> +static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
>  {
>      hwaddr pa;
>      if (!vq->notification) {
> @@ -218,7 +218,7 @@ void virtio_queue_set_notification(VirtQueue *vq, int 
> enable)
>  {
>      vq->notification = enable;
>      if (vq->vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
> -        vring_avail_event(vq, vring_avail_idx(vq));
> +        vring_set_avail_event(vq, vring_avail_idx(vq));
>      } else if (enable) {
>          vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
>      } else {
> @@ -469,7 +469,7 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
> 
>      i = head = virtqueue_get_head(vq, vq->last_avail_idx++);
>      if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
> -        vring_avail_event(vq, vq->last_avail_idx);
> +        vring_set_avail_event(vq, vq->last_avail_idx);
>      }
> 
>      if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_INDIRECT) {
> @@ -819,19 +819,6 @@ void virtio_irq(VirtQueue *vq)
>      virtio_notify_vector(vq->vdev, vq->vector);
>  }
> 
> -/* Assuming a given event_idx value from the other size, if
> - * we have just incremented index from old to new_idx,
> - * should we trigger an event? */
> -static inline int vring_need_event(uint16_t event, uint16_t new, uint16_t 
> old)
> -{
> -     /* Note: Xen has similar logic for notification hold-off
> -      * in include/xen/interface/io/ring.h with req_event and req_prod
> -      * corresponding to event_idx + 1 and new respectively.
> -      * Note also that req_event and req_prod in Xen start at 1,
> -      * event indexes in virtio start at 0. */
> -     return (uint16_t)(new - event - 1) < (uint16_t)(new - old);
> -}
> -
>  static bool vring_notify(VirtIODevice *vdev, VirtQueue *vq)
>  {
>      uint16_t old, new;
> @@ -852,7 +839,7 @@ static bool vring_notify(VirtIODevice *vdev, VirtQueue 
> *vq)
>      vq->signalled_used_valid = true;
>      old = vq->signalled_used;
>      new = vq->signalled_used = vring_used_idx(vq);
> -    return !v || vring_need_event(vring_used_event(vq), new, old);
> +    return !v || vring_need_event(vring_get_used_event(vq), new, old);
>  }
> 
>  void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)

Reviewed-by: Thomas Huth <address@hidden>