From patchwork Thu Aug 29 18:32:27 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Stabellini X-Patchwork-Id: 2851569 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 6F509C0AB5 for ; Thu, 29 Aug 2013 19:14:01 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8069D204CE for ; Thu, 29 Aug 2013 19:14:00 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4915D20418 for ; Thu, 29 Aug 2013 19:13:59 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VF74V-0006nT-NS; Thu, 29 Aug 2013 18:35:56 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VF73j-0004lQ-WA; Thu, 29 Aug 2013 18:35:08 +0000 Received: from smtp.citrix.com ([66.165.176.89]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VF72N-0004c4-C8 for linux-arm-kernel@lists.infradead.org; Thu, 29 Aug 2013 18:33:45 +0000 X-IronPort-AV: E=Sophos;i="4.89,984,1367971200"; d="scan'208";a="48860321" Received: from accessns.citrite.net (HELO FTLPEX01CL03.citrite.net) ([10.9.154.239]) by FTLPIPO01.CITRIX.COM with ESMTP; 29 Aug 2013 18:32:53 +0000 Received: from ukmail1.uk.xensource.com (10.80.16.128) by smtprelay.citrix.com (10.13.107.80) with Microsoft SMTP Server id 14.2.342.4; Thu, 29 Aug 2013 14:32:51 -0400 Received: from kaball.uk.xensource.com ([10.80.2.59]) by ukmail1.uk.xensource.com with esmtp (Exim 4.69) (envelope-from ) id 1VF71S-0008Qk-Mk; Thu, 29 Aug 2013 19:32:46 +0100 From: Stefano Stabellini To: Subject: [PATCH v5 06/13] xen: introduce XENMEM_exchange_and_pin and XENMEM_unpin Date: Thu, 29 Aug 2013 19:32:27 +0100 Message-ID: <1377801154-29215-6-git-send-email-stefano.stabellini@eu.citrix.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: MIME-Version: 1.0 X-DLP: MIA2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130829_143343_622607_728AF531 X-CRM114-Status: GOOD ( 17.96 ) X-Spam-Score: -9.4 (---------) Cc: Ian.Campbell@citrix.com, Stefano Stabellini , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, konrad.wilk@oracle.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-6.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP XENMEM_exchange can't be used by autotranslate guests because of two severe limitations: - it does not copy back the mfns into the out field for autotranslate guests; - it does not guarantee that the hypervisor won't change the p2m mappings for the exchanged pages while the guest is using them. Xen never promises to keep the p2m mapping stable for autotranslate guests in general. In practice it won't happen unless one uses uncommon features like memory sharing or paging. To overcome these problems I am introducing two new hypercalls. Signed-off-by: Stefano Stabellini Changes in v5: - better comment for XENMEM_exchange_and_pin return codes; Changes in v4: - rename XENMEM_get_dma_buf to XENMEM_exchange_and_pin; - rename XENMEM_put_dma_buf to XENMEM_unpin; - improve the documentation of the new hypercalls; - add a note about out.address_bits for XENMEM_exchange. --- include/xen/interface/memory.h | 37 +++++++++++++++++++++++++++++++++++++ 1 files changed, 37 insertions(+), 0 deletions(-) diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h index 2ecfe4f..fb0c6aa 100644 --- a/include/xen/interface/memory.h +++ b/include/xen/interface/memory.h @@ -66,6 +66,7 @@ struct xen_memory_exchange { /* * [IN] Details of memory extents to be exchanged (GMFN bases). * Note that @in.address_bits is ignored and unused. + * @out.address_bits should contain the address mask for the new pages. */ struct xen_memory_reservation in; @@ -263,4 +264,40 @@ struct xen_remove_from_physmap { }; DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap); +#define XENMEM_exchange_and_pin 26 +/* + * This hypercall is similar to XENMEM_exchange: it takes the same + * struct as an argument and it exchanges the pages passed in with a new + * set of pages. The new pages are going to be "pinned": it's guaranteed + * that their p2m mapping won't be changed until explicitly "unpinned". + * The content of the exchanged pages is lost. + * Only normal guest r/w memory can be pinned: no granted pages or + * ballooned pages. + * If return code is zero then @out.extent_list provides the DMA frame + * numbers of the newly-allocated memory. + * Returns zero on complete success, otherwise a negative error code: + * -ENOSYS if not implemented + * -EINVAL if the page is already pinned + * -EFAULT if an internal error occurs + * On complete success then always @nr_exchanged == @in.nr_extents. On + * partial success @nr_exchanged indicates how much work was done and a + * negative error code is returned. + */ + +#define XENMEM_unpin 27 +/* + * XENMEM_unpin unpins a set of pages, previously pinned by + * XENMEM_exchange_and_pin. After this call the p2m mapping of the pages can + * be transparently changed by the hypervisor, as usual. The pages are + * still accessible from the guest. + */ +struct xen_unpin { + /* + * [IN] Details of memory extents to be unpinned (GMFN bases). + * Note that @in.address_bits is ignored and unused. + */ + struct xen_memory_reservation in; +}; +DEFINE_GUEST_HANDLE_STRUCT(xen_unpin); + #endif /* __XEN_PUBLIC_MEMORY_H__ */