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authorJuergen Gross <jgross@suse.com>2021-07-30 09:18:04 +0200
committerJuergen Gross <jgross@suse.com>2021-08-30 11:57:50 +0200
commit30dcc56bba911db561c35d4131baf983a41023f8 (patch)
tree281131d05fb7f394239e93e204e89d9a496c34e3 /drivers/xen
parent2526cff7c4f944924f39043dc657189eccc4fe5c (diff)
downloadlinux-30dcc56bba911db561c35d4131baf983a41023f8.tar.bz2
xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests
XENFEAT_gnttab_map_avail_bits is always set in Xen 4.0 and newer. Remove coding assuming it might be zero. Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20210730071804.4302-4-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/gntdev.c36
1 files changed, 2 insertions, 34 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index a3e7be96527d..1e7f6b1c0c97 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -266,20 +266,13 @@ static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
{
struct gntdev_grant_map *map = data;
unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
- int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
+ int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte |
+ (1 << _GNTMAP_guest_avail0);
u64 pte_maddr;
BUG_ON(pgnr >= map->count);
pte_maddr = arbitrary_virt_to_machine(pte).maddr;
- /*
- * Set the PTE as special to force get_user_pages_fast() fall
- * back to the slow path. If this is not supported as part of
- * the grant map, it will be done afterwards.
- */
- if (xen_feature(XENFEAT_gnttab_map_avail_bits))
- flags |= (1 << _GNTMAP_guest_avail0);
-
gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
map->grants[pgnr].ref,
map->grants[pgnr].domid);
@@ -288,14 +281,6 @@ static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
return 0;
}
-#ifdef CONFIG_X86
-static int set_grant_ptes_as_special(pte_t *pte, unsigned long addr, void *data)
-{
- set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte));
- return 0;
-}
-#endif
-
int gntdev_map_grant_pages(struct gntdev_grant_map *map)
{
int i, err = 0;
@@ -1055,23 +1040,6 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
err = vm_map_pages_zero(vma, map->pages, map->count);
if (err)
goto out_put_map;
- } else {
-#ifdef CONFIG_X86
- /*
- * If the PTEs were not made special by the grant map
- * hypercall, do so here.
- *
- * This is racy since the mapping is already visible
- * to userspace but userspace should be well-behaved
- * enough to not touch it until the mmap() call
- * returns.
- */
- if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) {
- apply_to_page_range(vma->vm_mm, vma->vm_start,
- vma->vm_end - vma->vm_start,
- set_grant_ptes_as_special, NULL);
- }
-#endif
}
return 0;