Re: [Qemu-devel] [RFC 16/29] vhost+postcopy: Stash RAMBlock and offset

[Peter Xu]

On Wed, Jun 28, 2017 at 08:00:34PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> Stash the RAMBlock and offset for later use looking up
> addresses.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> ---
>  hw/virtio/trace-events |  1 +
>  hw/virtio/vhost-user.c | 11 +++++++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
> index f7be340a45..1fd194363a 100644
> --- a/hw/virtio/trace-events
> +++ b/hw/virtio/trace-events
> @@ -3,6 +3,7 @@
>  # hw/virtio/vhost-user.c
>  vhost_user_postcopy_listen(void) ""
>  vhost_user_set_mem_table_postcopy(uint64_t client_addr, uint64_t qhva, int 
> reply_i, int region_i) "client:%"PRIx64" for hva: %"PRIx64" reply %d region 
> %d"
> +vhost_user_set_mem_table_withfd(int index, const char *name, uint64_t 
> memory_size, uint64_t guest_phys_addr, uint64_t userspace_addr, uint64_t 
> offset) "%d:%s: size:%"PRIx64" GPA:%"PRIx64" QVA/userspace:%"PRIx64" RB 
> offset:%"PRIx64
>  
>  # hw/virtio/virtio.c
>  virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, unsigned 
> out_num) "elem %p size %zd in_num %u out_num %u"
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 6be3e7ff2d..3185af7a45 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -133,6 +133,11 @@ struct vhost_user {
>      NotifierWithReturn postcopy_notifier;
>      struct PostCopyFD  postcopy_fd;
>      uint64_t           postcopy_client_bases[VHOST_MEMORY_MAX_NREGIONS];
> +    RAMBlock          *region_rb[VHOST_MEMORY_MAX_NREGIONS];
> +    /* The offset from the start of the RAMBlock to the start of the
> +     * vhost region.
> +     */
> +    ram_addr_t         region_rb_offset[VHOST_MEMORY_MAX_NREGIONS];

Here the array size is VHOST_MEMORY_MAX_NREGIONS, while...

>  };
>  
>  static bool ioeventfd_enabled(void)
> @@ -324,8 +329,14 @@ static int vhost_user_set_mem_table(struct vhost_dev 
> *dev,
>          assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
>          mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
>                                       &offset);
> +        u->region_rb_offset[i] = offset;
> +        u->region_rb[i] = mr->ram_block;

... can i>=VHOST_MEMORY_MAX_NREGIONS here? Or do we only need to note
this down if fd > 0 below?  Thanks,

>          fd = memory_region_get_fd(mr);
>          if (fd > 0) {
> +            trace_vhost_user_set_mem_table_withfd(fd_num, mr->name,
> +                                                  reg->memory_size,
> +                                                  reg->guest_phys_addr,
> +                                                  reg->userspace_addr, 
> offset);
>              msg.payload.memory.regions[fd_num].userspace_addr = 
> reg->userspace_addr;
>              msg.payload.memory.regions[fd_num].memory_size  = 
> reg->memory_size;
>              msg.payload.memory.regions[fd_num].guest_phys_addr = 
> reg->guest_phys_addr;
> -- 
> 2.13.0
> 

-- 
Peter Xu