From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f74.google.com (mail-wr1-f74.google.com [209.85.221.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A58473128BE for ; Tue, 6 Jan 2026 16:22:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767716539; cv=none; b=ABRY/qHOEK/zivqLPozDSHV9KVvsGnlqMv+1AUWNx7hD6NXO9Vm0vzEaFbs9aCE4WYxY2uhwWNyalrGujUTDSJyRmWN2M7fF1I1cT8ZoJYAFAMxIGSP1AB77nWtpQ74c3rc7en9cHgP6QgYrbAlbtzB/QXTBspvpwcYaFUz40Rc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767716539; c=relaxed/simple; bh=5InwaW+ltmBMP59PvN83ke1/4IxUcekoo1u8qB7OebI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=UU2VxZrMWBD6J76RNayWA1gIZwTC8m1eS+8jbxmp/oaxqq3t9JMVybo4QAH0sWtK1/QwHjwJcRSzjMoZU8VDkjHbi25K66BknbPQiynTe6a22YUfeLXE4pJR8aWoCKW1TgoK86FKq1zj/m5v/aqRru85YkITK8s/KEXtbF3lHQ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--smostafa.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=liyfPgh2; arc=none smtp.client-ip=209.85.221.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--smostafa.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="liyfPgh2" Received: by mail-wr1-f74.google.com with SMTP id ffacd0b85a97d-4325ddc5babso568387f8f.0 for ; Tue, 06 Jan 2026 08:22:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1767716532; x=1768321332; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=pkB0OPkib0nA6oaGKP1dgUq2paM+wkefemX2KuvLm1c=; b=liyfPgh2YQWS789Dr+IwYwEa8qryo+szFZWXTLGxmDdGmf4LnO1jkunIRuFSqSZ96c AoIAUm/pbr1Ia91mEREsG/jKTxpwxKs0RObeaj9nhCH1VbmCLlgbpvh1Q+dxAGGZgKzk aFUggoYDVc0PHjmYapRb002E500fDHEcT0x/DL+8MTP4B4auOOUEfnjD/DlfHKGLbdKz n82Aj2Wg4SCqoF2xCyxjXWIUnsaD2hiae8H8t8xc8eoYwzFFo5b4PRdiH22mC7C3ievb E0XlZPRZzaPFj0cLelUb4B4Rf4wJ2vG+zF7NaC6lsCLuvIX27iw6c14pagaoWZIDWiCO l6/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767716532; x=1768321332; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=pkB0OPkib0nA6oaGKP1dgUq2paM+wkefemX2KuvLm1c=; b=s73KjZqTpWq+/RVGPuyyNQ43daBrbthXBvjs65J7//hfYwOOYZSXfifG1eL71n1MT6 F2XsxYXgagZ/BAs6hJO0TyyLS/VZwd7Q57cTJtfYfF1/vg6C5YYeIZQse25LUlPFOXCN lXR6on58DZpH0RkZDcbjoWKYakjkra2/CCshFsxvFkgsdAMQckYpke9iPpuwL+CD6wyN Vx8B92uAuohwtqesEZ712Jc//N1TnlQ3j17cLmeLJICceX6UHc8D30YT/2W5dJLaRxFl 5yDBCMS6LQIYq+C+1p9/qvLaJQdlIlk5ClZ5HegAVkULjWybZfsvSwE0eRPL50x/XshZ 3IRQ== X-Forwarded-Encrypted: i=1; AJvYcCVplW9wBkkvLUFSKL3w5Ifhggh1qN3pfdfWDhOomjeNHLEoSBwqvkZ6aYPMC7A9sShmo+lIdA==@lists.linux.dev X-Gm-Message-State: AOJu0Yy676P4NkzSJqCmzgdKVtt5QUrojCo65bDSzUt9Z/Q3Ld7dmHiq h083Lj/tg1Q5d52tmdgMS3Gk4mbiJa0CMQMfMlsp8cb0eJ1YoOp+Gc8oaOCYRuw0nyxqiquzJoX skYYvkgvYajmGYQ== X-Google-Smtp-Source: AGHT+IFQc8/Ih6tMLdszCIxSM7So3dMycZRLhJrz2no7PbcgYmWCWwIwp4Op4ZOQgvLHVVNUlH9GZoqjW7mvIg== X-Received: from wrbgv17.prod.google.com ([2002:a05:6000:4611:b0:430:f5d7:f015]) (user=smostafa job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:26c3:b0:42f:b707:56e6 with SMTP id ffacd0b85a97d-432bca45aabmr3978012f8f.34.1767716531688; Tue, 06 Jan 2026 08:22:11 -0800 (PST) Date: Tue, 6 Jan 2026 16:21:59 +0000 In-Reply-To: <20260106162200.2223655-1-smostafa@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260106162200.2223655-1-smostafa@google.com> X-Mailer: git-send-email 2.52.0.351.gbe84eed79e-goog Message-ID: <20260106162200.2223655-4-smostafa@google.com> Subject: [PATCH v5 3/4] iommu: debug-pagealloc: Track IOMMU pages From: Mostafa Saleh To: linux-mm@kvack.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: corbet@lwn.net, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, akpm@linux-foundation.org, vbabka@suse.cz, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, xiaqinxin@huawei.com, baolu.lu@linux.intel.com, rdunlap@infradead.org, Mostafa Saleh Content-Type: text/plain; charset="UTF-8" Using the new calls, use an atomic refcount to track how many times a page is mapped in any of the IOMMUs. For unmap we need to use iova_to_phys() to get the physical address of the pages. We use the smallest supported page size as the granularity of tracking per domain. This is important as it is possible to map pages and unmap them with larger sizes (as in map_sg()) cases. Reviewed-by: Lu Baolu Signed-off-by: Mostafa Saleh --- drivers/iommu/iommu-debug-pagealloc.c | 91 +++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) diff --git a/drivers/iommu/iommu-debug-pagealloc.c b/drivers/iommu/iommu-debug-pagealloc.c index 1d343421da98..86ccb310a4a8 100644 --- a/drivers/iommu/iommu-debug-pagealloc.c +++ b/drivers/iommu/iommu-debug-pagealloc.c @@ -29,19 +29,110 @@ struct page_ext_operations page_iommu_debug_ops = { .need = need_iommu_debug, }; +static struct page_ext *get_iommu_page_ext(phys_addr_t phys) +{ + struct page *page = phys_to_page(phys); + struct page_ext *page_ext = page_ext_get(page); + + return page_ext; +} + +static struct iommu_debug_metadata *get_iommu_data(struct page_ext *page_ext) +{ + return page_ext_data(page_ext, &page_iommu_debug_ops); +} + +static void iommu_debug_inc_page(phys_addr_t phys) +{ + struct page_ext *page_ext = get_iommu_page_ext(phys); + struct iommu_debug_metadata *d = get_iommu_data(page_ext); + + WARN_ON(atomic_inc_return_relaxed(&d->ref) <= 0); + page_ext_put(page_ext); +} + +static void iommu_debug_dec_page(phys_addr_t phys) +{ + struct page_ext *page_ext = get_iommu_page_ext(phys); + struct iommu_debug_metadata *d = get_iommu_data(page_ext); + + WARN_ON(atomic_dec_return_relaxed(&d->ref) < 0); + page_ext_put(page_ext); +} + +/* + * IOMMU page size doesn't have to match the CPU page size. So, we use + * the smallest IOMMU page size to refcount the pages in the vmemmap. + * That is important as both map and unmap has to use the same page size + * to update the refcount to avoid double counting the same page. + * And as we can't know from iommu_unmap() what was the original page size + * used for map, we just use the minimum supported one for both. + */ +static size_t iommu_debug_page_size(struct iommu_domain *domain) +{ + return 1UL << __ffs(domain->pgsize_bitmap); +} + void __iommu_debug_map(struct iommu_domain *domain, phys_addr_t phys, size_t size) { + size_t off, end; + size_t page_size = iommu_debug_page_size(domain); + + if (WARN_ON(!phys || check_add_overflow(phys, size, &end))) + return; + + for (off = 0 ; off < size ; off += page_size) { + if (!pfn_valid(__phys_to_pfn(phys + off))) + continue; + iommu_debug_inc_page(phys + off); + } +} + +static void __iommu_debug_update_iova(struct iommu_domain *domain, + unsigned long iova, size_t size, bool inc) +{ + size_t off, end; + size_t page_size = iommu_debug_page_size(domain); + + if (WARN_ON(check_add_overflow(iova, size, &end))) + return; + + for (off = 0 ; off < size ; off += page_size) { + phys_addr_t phys = iommu_iova_to_phys(domain, iova + off); + + if (!phys || !pfn_valid(__phys_to_pfn(phys))) + continue; + + if (inc) + iommu_debug_inc_page(phys); + else + iommu_debug_dec_page(phys); + } } void __iommu_debug_unmap_begin(struct iommu_domain *domain, unsigned long iova, size_t size) { + __iommu_debug_update_iova(domain, iova, size, false); } void __iommu_debug_unmap_end(struct iommu_domain *domain, unsigned long iova, size_t size, size_t unmapped) { + if (unmapped == size) + return; + + /* + * If unmap failed, re-increment the refcount, but if it unmapped + * larger size, decrement the extra part. + */ + if (unmapped < size) + __iommu_debug_update_iova(domain, iova + unmapped, + size - unmapped, true); + else + __iommu_debug_update_iova(domain, iova + size, + unmapped - size, false); } void iommu_debug_init(void) -- 2.52.0.351.gbe84eed79e-goog