From patchwork Tue Mar 21 02:52:51 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Zhang X-Patchwork-Id: 9635881 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 6ADAF601E9 for ; Tue, 21 Mar 2017 03:14:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6063D26E97 for ; Tue, 21 Mar 2017 03:14:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 553E4275A2; Tue, 21 Mar 2017 03:14:12 +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=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID 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 EE06D26E97 for ; Tue, 21 Mar 2017 03:14:11 +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 1cqADW-0001vl-9T; Tue, 21 Mar 2017 03:12:14 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cqADV-0001vK-4j for xen-devel@lists.xen.org; Tue, 21 Mar 2017 03:12:13 +0000 Received: from [85.158.139.211] by server-4.bemta-5.messagelabs.com id 56/04-13971-C0A90D85; Tue, 21 Mar 2017 03:12:12 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrDLMWRWlGSWpSXmKPExsVywNwkQpd71oU Ig21XdS2WfFzM4sDocXT3b6YAxijWzLyk/IoE1ozr2/8wF6yQqjh16jBjA+Nu4S5GLg4WgVtM Er3njzCBOEIC0xglXh5dC+RwckgI8EocWTaDFcL2k1h3dA4zRFE7o8SJNe2MIAk2AW2JH6t/g 9kiAtIS1z5fZgQpYhboZ5SY96gJrFtYIEXi8uy1LCA2i4CqxKeXPWANvAJeEnsmnWWD2CAncf LYZLB6TgFvia7nx9i7GDmAtnlJPJ9dO4GRbwEjwypGjeLUorLUIl0jM72kosz0jJLcxMwcXUM DU73c1OLixPTUnMSkYr3k/NxNjMBQqWdgYNzBeHuy3yFGSQ4mJVFeFcETEUJ8SfkplRmJxRnx RaU5qcWHGGU4OJQkeKu2AeUEi1LTUyvSMnOAQQuTluDgURLh/bAVKM1bXJCYW5yZDpE6xagoJ c7rDtInAJLIKM2Da4NFyiVGWSlhXkYGBgYhnoLUotzMElT5V4ziHIxKwrwVIFN4MvNK4Ka/Al rMBLQ48ecRkMUliQgpqQbGftGnLwJSo1NC+f5y/02NunXQYH5orVOlQMyt/Bj+A3ahXzMUZyR c3cG3ek6wq9UkiZxJNzRt7pwJ1N917WSR8a2qtew31eMf9FdP3e/Jfrht65GVckIXvDw4C8Wa LA24pHRObdA15GY5f+XBN5spd2ft8pabf83n97aD2/imKlxcnWS3TZVZiaU4I9FQi7moOBEAQ a1rjI8CAAA= X-Env-Sender: yu.c.zhang@linux.intel.com X-Msg-Ref: server-6.tower-206.messagelabs.com!1490065929!90286886!1 X-Originating-IP: [192.55.52.88] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogMTkyLjU1LjUyLjg4ID0+IDM3NDcyNQ==\n X-StarScan-Received: X-StarScan-Version: 9.2.3; banners=-,-,- X-VirusChecked: Checked Received: (qmail 25429 invoked from network); 21 Mar 2017 03:12:11 -0000 Received: from mga01.intel.com (HELO mga01.intel.com) (192.55.52.88) by server-6.tower-206.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 21 Mar 2017 03:12:11 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=intel.com; i=@intel.com; q=dns/txt; s=intel; t=1490065931; x=1521601931; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=7acGNsakx055GVfdT0tG9WlQ4bdyEl39WW7r7aEPyW0=; b=CePzh6gH6HVQPQtXHXXM7qFrRYyIijx+SQNFVepALjVt3bM1mP6YjR/I aoKndmqcPSt/pYucRlry/3Um/6za+Q==; Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Mar 2017 20:12:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,197,1486454400"; d="scan'208";a="69243027" Received: from zhangyu-optiplex-9020.bj.intel.com ([10.238.135.159]) by orsmga004.jf.intel.com with ESMTP; 20 Mar 2017 20:12:07 -0700 From: Yu Zhang To: xen-devel@lists.xen.org Date: Tue, 21 Mar 2017 10:52:51 +0800 Message-Id: <1490064773-26751-4-git-send-email-yu.c.zhang@linux.intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1490064773-26751-1-git-send-email-yu.c.zhang@linux.intel.com> References: <1490064773-26751-1-git-send-email-yu.c.zhang@linux.intel.com> Cc: Andrew Cooper , Paul Durrant , zhiyuan.lv@intel.com, Jan Beulich Subject: [Xen-devel] [PATCH v9 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 Reviewed-by: Jan Beulich --- Cc: Paul Durrant Cc: Jan Beulich Cc: Andrew Cooper changes in v3: - According to comments from Jan: clarify comments in hvmemul_do_io(). 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 | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c index 37139e6..52c726e 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) @@ -193,6 +213,9 @@ static int hvmemul_do_io( * - If the domain ioreq_server is NULL, assume there is a * race between the unbinding of ioreq server and guest fault * so re-try the instruction. + * + * - If the accesss is a read, this could be part of a + * read-modify-write instruction, emulate the read first. */ struct hvm_ioreq_server *s = NULL; p2m_type_t p2mt = p2m_invalid; @@ -226,6 +249,17 @@ static int hvmemul_do_io( vio->io_req.state = STATE_IOREQ_NONE; break; } + + /* + * 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; + } } }