Messages in this thread Patch in this message | | | From | Julien Grall <> | Subject | [PATCH v4 05/20] xen/grant: Add helper gnttab_page_grant_foreign_access_ref_one | Date | Mon, 7 Sep 2015 16:33:43 +0100 |
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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.grall@linaro.org> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
--- Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@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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