From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933641Ab1IOMmN (ORCPT ); Thu, 15 Sep 2011 08:42:13 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:27875 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933592Ab1IOMkw (ORCPT ); Thu, 15 Sep 2011 08:40:52 -0400 X-IronPort-AV: E=Sophos;i="4.68,387,1312171200"; d="scan'208";a="163268193" From: David Vrabel To: xen-devel@lists.xensource.com CC: Konrad Rzeszutek Wilk , linux-kernel@vger.kernel.org, "Andrew Morton" , David Vrabel Subject: [PATCH 1/6] xen: add functions for mapping foreign pages over pages Date: Thu, 15 Sep 2011 13:40:06 +0100 Message-ID: <1316090411-22608-2-git-send-email-david.vrabel@citrix.com> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1316090411-22608-1-git-send-email-david.vrabel@citrix.com> References: <1316090411-22608-1-git-send-email-david.vrabel@citrix.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Vrabel Add xenbus_map_ring_page() and xenbus_unmap_ring_page() which map and unmap foreign pages over a page instead of mapping them into vmalloc address space. This avoids having to do an expensive vmalloc_sync_all(). Signed-off-by: David Vrabel --- drivers/xen/xenbus/xenbus_client.c | 68 ++++++++++++++++++++++++++++++++++++ include/xen/xenbus.h | 3 ++ 2 files changed, 71 insertions(+), 0 deletions(-) diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c index cdacf92..504325b 100644 --- a/drivers/xen/xenbus/xenbus_client.c +++ b/drivers/xen/xenbus/xenbus_client.c @@ -32,6 +32,7 @@ #include #include +#include #include #include #include @@ -39,6 +40,7 @@ #include #include #include +#include const char *xenbus_strstate(enum xenbus_state state) { @@ -509,6 +511,44 @@ EXPORT_SYMBOL_GPL(xenbus_map_ring); /** + * xenbus_map_ring_page - map a foreign page into a kernel page + * @dev: xenbus device + * @gnt_ref: grant reference + * @page: return the page the foreign page has been mapped to + * + * Map a foreign page from another domain's grant table into a newly + * allocated page in this domain. The page must be unmapped with + * xenbus_unmap_ring_page(). + * + * Returns 0 on success, and -ENOMEM or GNTST_* (see + * include/xen/interface/grant_table.h) on error. + */ +int xenbus_map_ring_page(struct xenbus_device *dev, int gnt_ref, + struct page **page) +{ + struct page *new_page; + grant_ref_t handle; + int ret; + + new_page = alloc_page(GFP_KERNEL); + if (!new_page) + return -ENOMEM; + + ret = xenbus_map_ring(dev, gnt_ref, &handle, page_address(new_page)); + if (ret < 0) + goto err; + + new_page->private = handle; + *page = new_page; + return 0; + +err: + __free_page(new_page); + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_map_ring_page); + +/** * xenbus_unmap_ring_vfree * @dev: xenbus device * @vaddr: addr to unmap @@ -593,6 +633,34 @@ int xenbus_unmap_ring(struct xenbus_device *dev, } EXPORT_SYMBOL_GPL(xenbus_unmap_ring); +/** + * xenbus_unmap_ring_page - unmap an foreign page from a kernel page + * @dev: xenbus device + * @page: page the foreign page was mapped to + * + * Unmap a foreign page previously mapped with xenbus_map_ring_page(). + * The page is freed. + */ +void xenbus_unmap_ring_page(struct xenbus_device *dev, struct page *page) +{ + int ret; + + ret = xenbus_unmap_ring(dev, page->private, page_address(page)); + if (ret < 0) + return; + + /* + * Restore the original PTE of this page before freeing it. + */ + ret = HYPERVISOR_update_va_mapping( + (unsigned long)page_address(page), + mfn_pte(get_phys_to_machine(page_to_pfn(page)), PAGE_KERNEL), + 0); + BUG_ON(ret); + + __free_page(page); +} +EXPORT_SYMBOL_GPL(xenbus_unmap_ring_page); /** * xenbus_read_driver_state diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h index aceeca7..ebde2fd 100644 --- a/include/xen/xenbus.h +++ b/include/xen/xenbus.h @@ -212,10 +212,13 @@ int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr); int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref, grant_handle_t *handle, void *vaddr); +int xenbus_map_ring_page(struct xenbus_device *dev, int gnt_ref, + struct page **page); int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr); int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t handle, void *vaddr); +void xenbus_unmap_ring_page(struct xenbus_device *dev, struct page *page); int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port); int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port); -- 1.7.2.5