From patchwork Thu Feb 15 15:18:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 13558617 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BB9FAC48BC4 for ; Thu, 15 Feb 2024 15:18:55 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1radVc-0006l6-F7; Thu, 15 Feb 2024 10:18:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1radVY-0006as-6p; Thu, 15 Feb 2024 10:18:40 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1radVV-0005v5-S3; Thu, 15 Feb 2024 10:18:39 -0500 Received: from mail.maildlp.com (unknown [172.18.186.216]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4TbJWt5spZz689Hq; Thu, 15 Feb 2024 23:14:50 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id 4D6EF1400CD; Thu, 15 Feb 2024 23:18:35 +0800 (CST) Received: from SecurePC-101-06.china.huawei.com (10.122.247.231) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Thu, 15 Feb 2024 15:18:34 +0000 To: , Peter Maydell , Gregory Price , =?utf-8?q?Alex_Benn=C3=A9e?= , CC: , , Subject: [RFC PATCH 1/1] arm/ptw: Handle atomic updates of page tables entries in MMIO during PTW. Date: Thu, 15 Feb 2024 15:18:04 +0000 Message-ID: <20240215151804.2426-2-Jonathan.Cameron@huawei.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240215151804.2426-1-Jonathan.Cameron@huawei.com> References: <20240215151804.2426-1-Jonathan.Cameron@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.122.247.231] X-ClientProxiedBy: lhrpeml100004.china.huawei.com (7.191.162.219) To lhrpeml500005.china.huawei.com (7.191.163.240) Received-SPF: pass client-ip=185.176.79.56; envelope-from=jonathan.cameron@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Jonathan Cameron X-Patchwork-Original-From: Jonathan Cameron via From: Jonathan Cameron Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org I'm far from confident this handling here is correct. Hence RFC. In particular not sure on what locks I should hold for this to be even moderately safe. The function already appears to be inconsistent in what it returns as the CONFIG_ATOMIC64 block returns the endian converted 'eventual' value of the cmpxchg whereas the TCG_OVERSIZED_GUEST case returns the previous value. Signed-off-by: Jonathan Cameron --- target/arm/ptw.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/target/arm/ptw.c b/target/arm/ptw.c index 5eb3577bcd..37ddb4a4db 100644 --- a/target/arm/ptw.c +++ b/target/arm/ptw.c @@ -711,8 +711,38 @@ static uint64_t arm_casq_ptw(CPUARMState *env, uint64_t old_val, void *host = ptw->out_host; if (unlikely(!host)) { - fi->type = ARMFault_UnsuppAtomicUpdate; - return 0; + /* Can I do a load and store via the physical address */ + + bool locked = bql_locked(); + if (!locked) { + bql_lock(); + } + /* Page table in MMIO Memory Region */ + if (ptw->out_be) { + old_val = cpu_to_be64(old_val); + new_val = cpu_to_be64(new_val); + cpu_physical_memory_read(ptw->out_phys, &cur_val, 8); + if (cur_val == old_val) { + cpu_physical_memory_write(ptw->out_phys, &new_val, 8); + cur_val = be64_to_cpu(new_val); + } else { + cur_val = be64_to_cpu(cur_val); + } + } else { + old_val = cpu_to_le64(old_val); + new_val = cpu_to_le64(new_val); + cpu_physical_memory_read(ptw->out_phys, &cur_val, 8); + if (cur_val == old_val) { + cpu_physical_memory_write(ptw->out_phys, &new_val, 8); + cur_val = le64_to_cpu(new_val); + } else { + cur_val = le64_to_cpu(cur_val); + } + } + if (!locked) { + bql_unlock(); + } + return cur_val; } /*