Re: [PATCH 09/10] mini-os: prepare grantmap entry interface for use by PVH mode

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>]

Juergen Gross, le lun. 06 déc. 2021 08:23:36 +0100, a ecrit:
> Instead of passing the pointer of a grantmap entry to the
> _gntmap_[un]map_grant_ref() sub-functions use the map pointer and the
> entry index instead. This will be needed for PVH mode usage.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>

> ---
>  gntmap.c | 48 +++++++++++++++++++++++-------------------------
>  1 file changed, 23 insertions(+), 25 deletions(-)
> 
> diff --git a/gntmap.c b/gntmap.c
> index f6ab3ad..7ae8fe6 100644
> --- a/gntmap.c
> +++ b/gntmap.c
> @@ -55,36 +55,34 @@ struct gntmap_entry {
>  };
>  
>  static inline int
> -gntmap_entry_used(struct gntmap_entry *entry)
> +gntmap_entry_used(struct gntmap *map, int idx)
>  {
> -    return entry->host_addr != 0;
> +    return map->entries[idx].host_addr != 0;
>  }
>  
> -static struct gntmap_entry*
> -gntmap_find_free_entry(struct gntmap *map)
> +static int gntmap_find_free_entry(struct gntmap *map)
>  {
>      int i;
>  
>      for (i = 0; i < map->nentries; i++) {
> -        if (!gntmap_entry_used(&map->entries[i]))
> -            return &map->entries[i];
> +        if (!gntmap_entry_used(map, i))
> +            return i;
>      }
>  
>      DEBUG("(map=%p): all %d entries full",
>             map, map->nentries);
> -    return NULL;
> +    return -1;
>  }
>  
> -static struct gntmap_entry*
> -gntmap_find_entry(struct gntmap *map, unsigned long addr)
> +static int gntmap_find_entry(struct gntmap *map, unsigned long addr)
>  {
>      int i;
>  
>      for (i = 0; i < map->nentries; i++) {
>          if (map->entries[i].host_addr == addr)
> -            return &map->entries[i];
> +            return i;
>      }
> -    return NULL;
> +    return -1;
>  }
>  
>  int
> @@ -105,12 +103,13 @@ gntmap_set_max_grants(struct gntmap *map, int count)
>  }
>  
>  static int
> -_gntmap_map_grant_ref(struct gntmap_entry *entry, 
> +_gntmap_map_grant_ref(struct gntmap *map, int idx,
>                        unsigned long host_addr,
>                        uint32_t domid,
>                        uint32_t ref,
>                        int writable)
>  {
> +    struct gntmap_entry *entry = map->entries + idx;
>      struct gnttab_map_grant_ref op;
>      int rc;
>  
> @@ -135,8 +134,9 @@ _gntmap_map_grant_ref(struct gntmap_entry *entry,
>  }
>  
>  static int
> -_gntmap_unmap_grant_ref(struct gntmap_entry *entry)
> +_gntmap_unmap_grant_ref(struct gntmap *map, int idx)
>  {
> +    struct gntmap_entry *entry = map->entries + idx;
>      struct gnttab_unmap_grant_ref op;
>      int rc;
>  
> @@ -160,19 +160,19 @@ int
>  gntmap_munmap(struct gntmap *map, unsigned long start_address, int count)
>  {
>      int i, rc;
> -    struct gntmap_entry *ent;
> +    int idx;
>  
>      DEBUG("(map=%p, start_address=%lx, count=%d)",
>             map, start_address, count);
>  
>      for (i = 0; i < count; i++) {
> -        ent = gntmap_find_entry(map, start_address + PAGE_SIZE * i);
> -        if (ent == NULL) {
> +        idx = gntmap_find_entry(map, start_address + PAGE_SIZE * i);
> +        if (idx < 0) {
>              printk("gntmap: tried to munmap unknown page\n");
>              return -EINVAL;
>          }
>  
> -        rc = _gntmap_unmap_grant_ref(ent);
> +        rc = _gntmap_unmap_grant_ref(map, idx);
>          if (rc != 0)
>              return rc;
>      }
> @@ -189,7 +189,7 @@ gntmap_map_grant_refs(struct gntmap *map,
>                        int writable)
>  {
>      unsigned long addr;
> -    struct gntmap_entry *ent;
> +    int idx;
>      int i;
>  
>      DEBUG("(map=%p, count=%" PRIu32 ", "
> @@ -206,9 +206,9 @@ gntmap_map_grant_refs(struct gntmap *map,
>          return NULL;
>  
>      for (i = 0; i < count; i++) {
> -        ent = gntmap_find_free_entry(map);
> -        if (ent == NULL ||
> -            _gntmap_map_grant_ref(ent,
> +        idx = gntmap_find_free_entry(map);
> +        if (idx < 0 ||
> +            _gntmap_map_grant_ref(map, idx,
>                                    addr + PAGE_SIZE * i,
>                                    domids[i * domids_stride],
>                                    refs[i],
> @@ -233,15 +233,13 @@ gntmap_init(struct gntmap *map)
>  void
>  gntmap_fini(struct gntmap *map)
>  {
> -    struct gntmap_entry *ent;
>      int i;
>  
>      DEBUG("(map=%p)", map);
>  
>      for (i = 0; i < map->nentries; i++) {
> -        ent = &map->entries[i];
> -        if (gntmap_entry_used(ent))
> -            (void) _gntmap_unmap_grant_ref(ent);
> +        if (gntmap_entry_used(map, i))
> +            (void) _gntmap_unmap_grant_ref(map, i);
>      }
>  
>      xfree(map->entries);
> -- 
> 2.26.2
> 

-- 
Samuel
<L> pour moi le seul qui est autorisé à fasciser, c moi :-)