Re: [PATCH v2 07/20] vfio/common: Add VFIOBitmap and (de)alloc functions

[Alex Williamson]

On Wed, 22 Feb 2023 19:49:02 +0200
Avihai Horon <avihaih@nvidia.com> wrote:

> There are already two places where dirty page bitmap allocation and
> calculations are done in open code. With device dirty page tracking
> being added in next patches, there are going to be even more places.
> 
> To avoid code duplication, introduce VFIOBitmap struct and corresponding
> alloc and dealloc functions and use them where applicable.
> 
> Signed-off-by: Avihai Horon <avihaih@nvidia.com>
> ---
>  hw/vfio/common.c | 89 ++++++++++++++++++++++++++++++++----------------
>  1 file changed, 60 insertions(+), 29 deletions(-)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index ac93b85632..84f08bdbbb 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -320,6 +320,41 @@ const MemoryRegionOps vfio_region_ops = {
>   * Device state interfaces
>   */
>  
> +typedef struct {
> +    unsigned long *bitmap;
> +    hwaddr size;
> +    hwaddr pages;
> +} VFIOBitmap;
> +
> +static VFIOBitmap *vfio_bitmap_alloc(hwaddr size)
> +{
> +    VFIOBitmap *vbmap = g_try_new0(VFIOBitmap, 1);
> +    if (!vbmap) {
> +        errno = ENOMEM;
> +
> +        return NULL;
> +    }
> +
> +    vbmap->pages = REAL_HOST_PAGE_ALIGN(size) / qemu_real_host_page_size();
> +    vbmap->size = ROUND_UP(vbmap->pages, sizeof(__u64) * BITS_PER_BYTE) /
> +                                         BITS_PER_BYTE;
> +    vbmap->bitmap = g_try_malloc0(vbmap->size);
> +    if (!vbmap->bitmap) {
> +        g_free(vbmap);
> +        errno = ENOMEM;
> +
> +        return NULL;
> +    }
> +
> +    return vbmap;
> +}
> +
> +static void vfio_bitmap_dealloc(VFIOBitmap *vbmap)
> +{
> +    g_free(vbmap->bitmap);
> +    g_free(vbmap);
> +}

Nit, '_alloc' and '_free' seems like a more standard convention.
Thanks,

Alex