From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Cc: Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH v2 3/3] xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests
Date: Fri, 30 Jul 2021 09:18:04 +0200 [thread overview]
Message-ID: <20210730071804.4302-4-jgross@suse.com> (raw)
In-Reply-To: <20210730071804.4302-1-jgross@suse.com>
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>
---
drivers/xen/gntdev.c | 36 ++----------------------------------
1 file 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;
--
2.26.2
next prev parent reply other threads:[~2021-07-30 7:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 7:18 [PATCH v2 0/3] xen: remove some checks for always present Xen features Juergen Gross
2021-07-30 7:18 ` [PATCH v2 1/3] xen: check required " Juergen Gross
2021-07-30 7:18 ` [PATCH v2 2/3] xen: assume XENFEAT_mmu_pt_update_preserve_ad being set for pv guests Juergen Gross
2021-07-30 7:18 ` Juergen Gross [this message]
2021-07-30 13:10 ` [PATCH v2 0/3] xen: remove some checks for always present Xen features Boris Ostrovsky
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210730071804.4302-4-jgross@suse.com \
--to=jgross@suse.com \
--cc=boris.ostrovsky@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=sstabellini@kernel.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).