From patchwork Mon Jul 24 12:12:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Petr Tesarik X-Patchwork-Id: 13324547 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.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 83127C04FE1 for ; Mon, 24 Jul 2023 12:16:04 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.568852.888923 (Exim 4.92) (envelope-from ) id 1qNuTd-0002Li-Ir; Mon, 24 Jul 2023 12:15:49 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 568852.888923; Mon, 24 Jul 2023 12:15:49 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qNuTd-0002LZ-FO; Mon, 24 Jul 2023 12:15:49 +0000 Received: by outflank-mailman (input) for mailman id 568852; Mon, 24 Jul 2023 12:15:48 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qNuTc-0000u4-AW for xen-devel@lists.xenproject.org; Mon, 24 Jul 2023 12:15:48 +0000 Received: from frasgout13.his.huawei.com (unknown [14.137.139.46]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id d2571d90-2a1b-11ee-b23a-6b7b168915f2; Mon, 24 Jul 2023 14:15:47 +0200 (CEST) Received: from mail02.huawei.com (unknown [172.18.147.228]) by frasgout13.his.huawei.com (SkyGuard) with ESMTP id 4R8f3K6fGRz9yXKP for ; Mon, 24 Jul 2023 20:04:29 +0800 (CST) Received: from A2101119013HW2.china.huawei.com (unknown [10.81.222.124]) by APP2 (Coremail) with SMTP id GxC2BwA3_lTGar5ky0byBA--.27936S11; Mon, 24 Jul 2023 13:15:20 +0100 (CET) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d2571d90-2a1b-11ee-b23a-6b7b168915f2 From: Petr Tesarik To: Stefano Stabellini , Russell King , Thomas Bogendoerfer , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), "H. Peter Anvin" , Greg Kroah-Hartman , "Rafael J. Wysocki" , Juergen Gross , Oleksandr Tyshchenko , Christoph Hellwig , Marek Szyprowski , Robin Murphy , Jonathan Corbet , Andy Shevchenko , Hans de Goede , Sakari Ailus , James Seo , James Clark , Kees Cook , xen-devel@lists.xenproject.org (moderated list:XEN HYPERVISOR ARM), linux-arm-kernel@lists.infradead.org (moderated list:ARM PORT), linux-kernel@vger.kernel.org (open list), linux-mips@vger.kernel.org (open list:MIPS), iommu@lists.linux.dev (open list:XEN SWIOTLB SUBSYSTEM) Cc: Roberto Sassu , petr@tesarici.cz Subject: [PATCH v5 9/9] swiotlb: search the software IO TLB only if the device makes use of it Date: Mon, 24 Jul 2023 14:12:45 +0200 Message-Id: <5a2cf3a8b5a20c739a2369548ec49e7547827a92.1690200599.git.petr.tesarik.ext@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-CM-TRANSID: GxC2BwA3_lTGar5ky0byBA--.27936S11 X-Coremail-Antispam: 1UD129KBjvJXoWxZF15Ww18ZF1fWr1UtFW7XFb_yoWrXFy3pF 98AFZ8KayqqryxGryxCF18uF1agw4vk3yxurWagrnYkr1UJwnYqF1DKrWav3s5Ar47ZF43 tryj9rsYkr17Xr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUmv14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26r4j6F4UM28EF7xvwVC2z280aVCY1x0267AKxVWxJr0_ GcWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2I x0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8 JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2Y2 ka0xkIwI1lc7CjxVAKzI0EY4vE52x082I5MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCj c4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4 CE17CEb7AF67AKxVWrXVW8Jr1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW8JVW5 JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI42IY6xAIw20EY4v20xvaj40_Jr 0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxVWxJr0_GcJv cSsGvfC2KfnxnUUI43ZEXa7VUjyCJPUUUUU== X-CM-SenderInfo: hshw23xhvd2x3n6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected From: Petr Tesarik Skip searching the software IO TLB if a device has never used it, making sure these devices are not affected by the introduction of multiple IO TLB memory pools. Additional memory barrier is required to ensure that the new value of the flag is visible to other CPUs after mapping a new bounce buffer. For efficiency, the flag check should be inlined, and then the memory barrier must be moved to is_swiotlb_buffer(). However, it can replace the existing barrier in swiotlb_find_pool(), because all callers use is_swiotlb_buffer() first to verify that the buffer address belongs to the software IO TLB. Signed-off-by: Petr Tesarik --- include/linux/device.h | 2 ++ include/linux/swiotlb.h | 7 ++++++- kernel/dma/swiotlb.c | 14 ++++++-------- 3 files changed, 14 insertions(+), 9 deletions(-) diff --git a/include/linux/device.h b/include/linux/device.h index 5fd89c9d005c..6fc808d22bfd 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -628,6 +628,7 @@ struct device_physical_location { * @dma_io_tlb_mem: Software IO TLB allocator. Not for driver use. * @dma_io_tlb_pools: List of transient swiotlb memory pools. * @dma_io_tlb_lock: Protects changes to the list of active pools. + * @dma_uses_io_tlb: %true if device has used the software IO TLB. * @archdata: For arch-specific additions. * @of_node: Associated device tree node. * @fwnode: Associated device node supplied by platform firmware. @@ -737,6 +738,7 @@ struct device { #ifdef CONFIG_SWIOTLB_DYNAMIC struct list_head dma_io_tlb_pools; spinlock_t dma_io_tlb_lock; + bool dma_uses_io_tlb; #endif /* arch specific additions */ struct dev_archdata archdata; diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 8a9249685d0d..b3cf602922dc 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -172,8 +172,13 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr) if (!mem) return false; - if (IS_ENABLED(CONFIG_SWIOTLB_DYNAMIC)) + if (IS_ENABLED(CONFIG_SWIOTLB_DYNAMIC)) { + /* Pairs with smp_wmb() in swiotlb_find_slots() and + * swiotlb_dyn_alloc(), which modify the RCU lists. + */ + smp_rmb(); return swiotlb_find_pool(dev, paddr); + } return paddr >= mem->defpool.start && paddr < mem->defpool.end; } diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 3156bb6aa343..87b8c2417c68 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -730,7 +730,7 @@ static void swiotlb_dyn_alloc(struct work_struct *work) add_mem_pool(mem, pool); - /* Pairs with smp_rmb() in swiotlb_find_pool(). */ + /* Pairs with smp_rmb() in is_swiotlb_buffer(). */ smp_wmb(); } @@ -764,11 +764,6 @@ struct io_tlb_pool *swiotlb_find_pool(struct device *dev, phys_addr_t paddr) struct io_tlb_mem *mem = dev->dma_io_tlb_mem; struct io_tlb_pool *pool; - /* Pairs with smp_wmb() in swiotlb_find_slots() and - * swiotlb_dyn_alloc(), which modify the RCU lists. - */ - smp_rmb(); - rcu_read_lock(); list_for_each_entry_rcu(pool, &mem->pools, node) { if (paddr >= pool->start && paddr < pool->end) @@ -813,6 +808,7 @@ void swiotlb_dev_init(struct device *dev) #ifdef CONFIG_SWIOTLB_DYNAMIC INIT_LIST_HEAD(&dev->dma_io_tlb_pools); spin_lock_init(&dev->dma_io_tlb_lock); + dev->dma_uses_io_tlb = false; #endif } @@ -1157,9 +1153,11 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, list_add_rcu(&pool->node, &dev->dma_io_tlb_pools); spin_unlock_irqrestore(&dev->dma_io_tlb_lock, flags); - /* Pairs with smp_rmb() in swiotlb_find_pool(). */ - smp_wmb(); found: + dev->dma_uses_io_tlb = true; + /* Pairs with smp_rmb() in is_swiotlb_buffer() */ + smp_wmb(); + *retpool = pool; return index; }