Many PV drivers contain the idiom:
pfn = page_to_gfn(...) /* Or similar */
gnttab_grant_foreign_access_ref
Replace it by a new helper. Note that when Linux is using a different
page granularity than Xen, the helper only gives access to the first 4KB
grant.
This is useful where drivers are allocating a full Linux page for each
grant.
Also include xen/interface/grant_table.h rather than xen/grant_table.h in
asm/page.h for x86 to fix a compilation issue [1]. Only the former is
useful in order to get the structure definition.
[1] Interdependency between asm/page.h and xen/grant_table.h which result
to page_mfn not being defined when necessary.
Signed-off-by: Julien Grall <julien.gr...@linaro.org>
Reviewed-by: David Vrabel <david.vra...@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
---
Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Cc: Boris Ostrovsky <boris.ostrov...@oracle.com>
Changes in v3:
- Rename gnttab_page_grant_foreign_access_ref into
gnttab_page_grant_foreign_access_ref_one
- Fix typo in the commit message
- s/mfn/gfn based on the new naming
- Add David and Stefano's reviewed-by
Changes in v2:
- Patch added
---
include/xen/grant_table.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 05b5b08..e17a4b3 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -131,6 +131,15 @@ void gnttab_cancel_free_callback(struct
gnttab_free_callback *callback);
void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
unsigned long frame, int readonly);
+/* Give access to the first 4K of the page */
+static inline void gnttab_page_grant_foreign_access_ref_one(
+ grant_ref_t ref, domid_t domid,
+ struct page *page, int readonly)
+{
+ gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
+ readonly);
+}
+
void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
unsigned long pfn);
--
2.1.4
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