From patchwork Wed Mar 8 15:33:50 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Zhang X-Patchwork-Id: 9611473 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 69EEC60414 for ; Wed, 8 Mar 2017 15:54:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 69E8D2846A for ; Wed, 8 Mar 2017 15:54:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5EBEB2857C; Wed, 8 Mar 2017 15:54:44 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 0A11F2846A for ; Wed, 8 Mar 2017 15:54:44 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cldtT-0003TI-OM; Wed, 08 Mar 2017 15:52:51 +0000 Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cldtS-0003Sl-QG for xen-devel@lists.xen.org; Wed, 08 Mar 2017 15:52:50 +0000 Received: from [85.158.137.68] by server-9.bemta-3.messagelabs.com id AF/8B-20914-2D820C85; Wed, 08 Mar 2017 15:52:50 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrHLMWRWlGSWpSXmKPExsVywNxEW/eixoE Ig0efFCyWfFzM4sDocXT3b6YAxijWzLyk/IoE1ozvZ+4xFayXqph16RBbA+Nq4S5GTg4hgQqJ +2cXMoPYEgK8EkeWzWCFsP0ktvVPYYaoaWeU2LNZFcRmE9CW+LH6NyOILSIgLXHt82Ugm4uDW aCfUWLeoyawZmGBFIkt53cwgdgsAqoSDxtfgMV5BbwkXu45BbVMTuLksclgcU4Bb4mmriuMEM u8JH6v3sk0gZF3ASPDKkaN4tSistQiXSMjvaSizPSMktzEzBxdQwNjvdzU4uLE9NScxKRiveT 83E2MwHCoZ2Bg3ME49YTfIUZJDiYlUd6rqgcihPiS8lMqMxKLM+KLSnNSiw8xynBwKEnwSqsD 5QSLUtNTK9Iyc4CBCZOW4OBREuF9CJLmLS5IzC3OTIdInWJUlBLn9QFJCIAkMkrz4Npg0XCJU VZKmJeRgYFBiKcgtSg3swRV/hWjOAejkjDvcpApPJl5JXDTXwEtZgJarO26F2RxSSJCSqqBkW /mcfcvRxc93WTdqa7Nlx/6+oNBavu77ef310tfCxR9Ir9PxUpRX7/eYKLG5h/vYsK75YLXbRf hWDb/Es//rba/5NJi8upsWBe3ltutipo3ccLXN4qcGz40x8e9XP2qzfuI5wc2jtzX54X03kv8 mNXT3OvQl/CZwfmDqcW7te2J5cxtXjOOKrEUZyQaajEXFScCAFNyFj+BAgAA X-Env-Sender: yu.c.zhang@linux.intel.com X-Msg-Ref: server-15.tower-31.messagelabs.com!1488988363!85212966!2 X-Originating-IP: [192.55.52.43] X-SpamReason: No, hits=0.5 required=7.0 tests=BODY_RANDOM_LONG X-StarScan-Received: X-StarScan-Version: 9.2.3; banners=-,-,- X-VirusChecked: Checked Received: (qmail 19763 invoked from network); 8 Mar 2017 15:52:49 -0000 Received: from mga05.intel.com (HELO mga05.intel.com) (192.55.52.43) by server-15.tower-31.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 8 Mar 2017 15:52:49 -0000 Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga105.fm.intel.com with ESMTP; 08 Mar 2017 07:52:48 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,264,1486454400"; d="scan'208";a="65498327" Received: from zhangyu-optiplex-9020.bj.intel.com ([10.238.135.159]) by orsmga004.jf.intel.com with ESMTP; 08 Mar 2017 07:52:47 -0800 From: Yu Zhang To: xen-devel@lists.xen.org Date: Wed, 8 Mar 2017 23:33:50 +0800 Message-Id: <1488987232-12349-4-git-send-email-yu.c.zhang@linux.intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1488987232-12349-1-git-send-email-yu.c.zhang@linux.intel.com> References: <1488987232-12349-1-git-send-email-yu.c.zhang@linux.intel.com> Cc: Andrew Cooper , Paul Durrant , zhiyuan.lv@intel.com, Jan Beulich Subject: [Xen-devel] [PATCH v7 3/5] x86/ioreq server: Handle read-modify-write cases for p2m_ioreq_server pages. X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP In ept_handle_violation(), write violations are also treated as read violations. And when a VM is accessing a write-protected address with read-modify-write instructions, the read emulation process is triggered first. For p2m_ioreq_server pages, current ioreq server only forwards the write operations to the device model. Therefore when such page is being accessed by a read-modify-write instruction, the read operations should be emulated here in hypervisor. This patch provides such a handler to copy the data to the buffer. Note: MMIOs with p2m_mmio_dm type do not need such special treatment because both reads and writes will go to the device mode. Signed-off-by: Paul Durrant Signed-off-by: Yu Zhang --- Cc: Paul Durrant Cc: Jan Beulich Cc: Andrew Cooper changes in v2: - According to comments from Jan: rename mem_ops to ioreq_server_ops. - According to comments from Jan: use hvm_copy_from_guest_phys() in ioreq_server_read(), instead of do it by myself. --- xen/arch/x86/hvm/emulate.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c index fb56f7b..9744dcb 100644 --- a/xen/arch/x86/hvm/emulate.c +++ b/xen/arch/x86/hvm/emulate.c @@ -94,6 +94,26 @@ static const struct hvm_io_handler null_handler = { .ops = &null_ops }; +static int ioreq_server_read(const struct hvm_io_handler *io_handler, + uint64_t addr, + uint32_t size, + uint64_t *data) +{ + if ( hvm_copy_from_guest_phys(data, addr, size) != HVMCOPY_okay ) + return X86EMUL_UNHANDLEABLE; + + return X86EMUL_OKAY; +} + +static const struct hvm_io_ops ioreq_server_ops = { + .read = ioreq_server_read, + .write = null_write +}; + +static const struct hvm_io_handler ioreq_server_handler = { + .ops = &ioreq_server_ops +}; + static int hvmemul_do_io( bool_t is_mmio, paddr_t addr, unsigned long *reps, unsigned int size, uint8_t dir, bool_t df, bool_t data_is_addr, uintptr_t data) @@ -197,6 +217,10 @@ static int hvmemul_do_io( * - If the IOREQ_MEM_ACCESS_WRITE flag is not set, treat it * like a normal PIO or MMIO that doesn't have an ioreq * server (i.e., by ignoring it). + * + * - If the accesss is a read, this could be part of a + * read-modify-write instruction, emulate the read so that we + * have it. */ struct hvm_ioreq_server *s = NULL; p2m_type_t p2mt = p2m_invalid; @@ -226,6 +250,17 @@ static int hvmemul_do_io( } /* + * This is part of a read-modify-write instruction. + * Emulate the read part so we have the value cached. + */ + if ( dir == IOREQ_READ ) + { + rc = hvm_process_io_intercept(&ioreq_server_handler, &p); + vio->io_req.state = STATE_IOREQ_NONE; + break; + } + + /* * If the IOREQ_MEM_ACCESS_WRITE flag is not set, * we should set s to NULL, and just ignore such * access.