From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933269Ab1LFK4x (ORCPT ); Tue, 6 Dec 2011 05:56:53 -0500 Received: from acsinet15.oracle.com ([141.146.126.227]:28283 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933118Ab1LFK4w (ORCPT ); Tue, 6 Dec 2011 05:56:52 -0500 From: annie.li@oracle.com To: xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org, konrad.wilk@oracle.com, jeremy@goop.org Cc: kurt.hackel@oracle.com, paul.durrant@citrix.com, Ian.Campbell@citrix.com, annie.li@oracle.com Subject: [PATCH 1/2] xen/granttable: Support sub-page grants Date: Tue, 6 Dec 2011 18:56:39 +0800 Message-Id: <1323168999-4434-1-git-send-email-annie.li@oracle.com> X-Mailer: git-send-email 1.7.6.4 In-Reply-To: <4EDDF41E.8070200@oracle.com> References: <4EDDF41E.8070200@oracle.com> X-Source-IP: ucsinet21.oracle.com [156.151.31.93] X-CT-RefId: str=0001.0A090205.4EDDF4EF.00A4,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Annie Li -- They can't be used to map the page (so can only be used in a GNTTABOP_copy hypercall). -- It's possible to grant access with a finer granularity than whole pages. -- Xen guarantees that they can be revoked quickly (a normal map grant can only be revoked with the cooperation of the domain which has been granted access). Signed-off-by: Annie Li --- drivers/xen/grant-table.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/xen/grant_table.h | 13 +++++++++++++ 2 files changed, 54 insertions(+), 0 deletions(-) diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index bd325fd..7a0f4d1 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -261,6 +261,47 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned long frame, } EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access); +int gnttab_grant_foreign_access_subpage_v2(domid_t domid, unsigned long frame, + int flags, unsigned page_off, + unsigned length) +{ + int ref; + + ref = get_free_entries(1); + if (unlikely(ref < 0)) + return -ENOSPC; + + gnttab_grant_foreign_access_ref_subpage_v2(ref, domid, frame, flags, + page_off, length); + + return ref; +} +EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage_v2); + +void gnttab_grant_foreign_access_ref_subpage_v2(grant_ref_t ref, domid_t domid, + unsigned long frame, int flags, + unsigned page_off, + unsigned length) +{ + BUG_ON(flags & (GTF_accept_transfer | GTF_reading | + GTF_writing | GTF_transitive)); + BUG_ON(grant_table_version == 1); + gnttab_shared.v2[ref].sub_page.frame = frame; + gnttab_shared.v2[ref].sub_page.page_off = page_off; + gnttab_shared.v2[ref].sub_page.length = length; + gnttab_shared.v2[ref].hdr.domid = domid; + wmb(); + gnttab_shared.v2[ref].hdr.flags = + GTF_permit_access | GTF_sub_page | flags; +} +EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref_subpage_v2); + +bool gnttab_subpage_trans_grants_available(void) +{ + return grant_table_version == 2; +} +EXPORT_SYMBOL_GPL(gnttab_subpage_trans_grants_available); + static int gnttab_query_foreign_access_v1(grant_ref_t ref) { return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing); diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index fea4954..7e43652 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -62,6 +62,15 @@ int gnttab_resume(void); int gnttab_grant_foreign_access(domid_t domid, unsigned long frame, int readonly); +int gnttab_grant_foreign_access_subpage_v2(domid_t domid, unsigned long frame, + int flags, unsigned page_off, + unsigned length); + +/* + * Are sub-page or transitive grants available on this version of Xen? Returns + * true if they are, and false if they're not. + */ +bool gnttab_subpage_trans_grants_available(void); /* * End access through the given grant reference, iff the grant entry is no @@ -108,6 +117,10 @@ 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); +void gnttab_grant_foreign_access_ref_subpage_v2(grant_ref_t ref, domid_t domid, + unsigned long frame, int flags, + unsigned page_off, + unsigned length); void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid, unsigned long pfn); -- 1.7.6.4