From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 380282C181; Mon, 6 Jul 2026 06:05:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783317924; cv=none; b=MDmkxIdsY8TbcAnBSFph4CB3UIW2yGlC6aSdkylLw1CzhgRft1sNEWQ0wGRae4crI6h2X/qfEwnpN68QAfTitr/lMkACX4H6vFs1gkJ+rNctGA2tR71+sgakL3Qf6iwse4hzLj+xERYgMKuNjhglgloV18xFYjuXjOmUrsb/8WQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783317924; c=relaxed/simple; bh=5Fh/HF+sh6aJFodEmfl0wYTeQLetdm7629n3hJL8VIY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nq+p3kBiJY1HxJPXszaRcwrrQMvTcjaEV5/kZHINEg0JZ0pr+8RHiWg6JilLJ6xxaYGfoddBuRlgICPjqs1F/m5MtmCxQ7Q6RMBqseHqfGY0jNePWeeaTkEk1P8gBnbZ1SlcqWMpDm63azSS6JxP7uu8Z7whaK8BIhEfaePtUyM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L8JG8hBs; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="L8JG8hBs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 055D61F00A3A; Mon, 6 Jul 2026 06:05:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783317923; bh=e2V3VqU4Wtz37YK1GAfo+NDcDqEETC18sWhhjPNJ4SU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=L8JG8hBsi7TeebOUuOSZlVgb8uOzreNkz4Lu8dOGqF6RK+IsodD4hcPNs3XwR8r30 8+9AbGoKFF16IhQX6xvaIQ6WDdgF+08nRLe+YFpiGh82047xona2TEvgDy8SwEyNYY h60+QAnm28YIAtDPwj7dXKZkCoZkWIigteci+qjDqqYIlHmjnxMqmcb9r3+AntLSxw GzLIMudvqM5YBG80WnBD/aV4um2euTd6qc69SPNLeux04yUQ4BJAfTr0IMxGxFZJIS lkXPTeSe9H89xpQ3IQ3RhLxjTw6hh1bKxY2QEctLOoKQy+KMjRnjwf8+BdEUaLQOwH jbSZYDPBul29Q== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev Cc: "Aneesh Kumar K.V (Arm)" , Catalin Marinas , Jason Gunthorpe , Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Suzuki K Poulose , Thomas Gleixner , Will Deacon Subject: [PATCH v5 05/10] swiotlb: Align shared IO TLB pools to the shared granule size Date: Mon, 6 Jul 2026 11:34:27 +0530 Message-ID: <20260706060432.1375570-6-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260706060432.1375570-1-aneesh.kumar@kernel.org> References: <20260706060432.1375570-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit swiotlb pools used by confidential-computing guests are shared with the host and therefore must be converted at the host shared-granule size. A PAGE_SIZE-sized or PAGE_SIZE-aligned pool is not sufficient when the host tracks shared state at a larger granularity. Round swiotlb pool sizes to mem_cc_shared_granule_size(), allocate the pools at that alignment, and use the same aligned size when decrypting, encrypting and freeing pool memory. Apply the same rule to dynamically allocated swiotlb pools. Signed-off-by: Aneesh Kumar K.V (Arm) --- kernel/dma/swiotlb.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 897aba538c5b..1d77746b6f31 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -287,7 +287,8 @@ void __init swiotlb_update_mem_attributes(void) if (!mem->nslabs || mem->late_alloc) return; - bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT); + + bytes = mem_cc_align_to_shared_granule(mem->nslabs << IO_TLB_SHIFT); if (io_tlb_default_mem.cc_shared) { int ret; @@ -354,8 +355,8 @@ static void __init *swiotlb_memblock_alloc(unsigned long nslabs, unsigned int flags, int (*remap)(void *tlb, unsigned long nslabs)) { - size_t bytes = PAGE_ALIGN(nslabs << IO_TLB_SHIFT); void *tlb; + size_t bytes = mem_cc_align_to_shared_granule(nslabs << IO_TLB_SHIFT); /* * By default allocate the bounce buffer memory from low memory, but @@ -363,9 +364,9 @@ static void __init *swiotlb_memblock_alloc(unsigned long nslabs, * memory encryption. */ if (flags & SWIOTLB_ANY) - tlb = memblock_alloc(bytes, PAGE_SIZE); + tlb = memblock_alloc(bytes, mem_cc_shared_granule_size()); else - tlb = memblock_alloc_low(bytes, PAGE_SIZE); + tlb = memblock_alloc_low(bytes, mem_cc_shared_granule_size()); if (!tlb) { pr_warn("%s: Failed to allocate %zu bytes tlb structure\n", @@ -374,7 +375,7 @@ static void __init *swiotlb_memblock_alloc(unsigned long nslabs, } if (remap && remap(tlb, nslabs) < 0) { - memblock_free(tlb, PAGE_ALIGN(bytes)); + memblock_free(tlb, bytes); pr_warn("%s: Failed to remap %zu bytes\n", __func__, bytes); return NULL; } @@ -496,7 +497,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask, swiotlb_adjust_nareas(num_possible_cpus()); retry: - order = get_order(nslabs << IO_TLB_SHIFT); + order = get_order(mem_cc_align_to_shared_granule(nslabs << IO_TLB_SHIFT)); nslabs = SLABS_PER_PAGE << order; while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) { @@ -505,6 +506,8 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask, if (vstart) break; order--; + if (order < get_order(mem_cc_shared_granule_size())) + break; nslabs = SLABS_PER_PAGE << order; retried = true; } @@ -585,7 +588,7 @@ void __init swiotlb_exit(void) pr_info("tearing down default memory pool\n"); tbl_vaddr = (unsigned long)phys_to_virt(mem->start); - tbl_size = PAGE_ALIGN(mem->end - mem->start); + tbl_size = mem_cc_align_to_shared_granule(mem->end - mem->start); slots_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), mem->nslabs)); if (io_tlb_default_mem.cc_shared) { @@ -629,12 +632,14 @@ void __init swiotlb_exit(void) static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, u64 phys_limit, unsigned long attrs) { - unsigned int order = get_order(bytes); bool cc_shared = attrs & __DMA_ATTR_ALLOC_CC_SHARED; + unsigned int order; struct page *page; phys_addr_t paddr; void *vaddr; + bytes = mem_cc_align_to_shared_granule(bytes); + order = get_order(bytes); page = alloc_pages(gfp, order); if (!page) return NULL; @@ -725,6 +730,7 @@ static void swiotlb_free_tlb(void *vaddr, size_t bytes, bool cc_shared) dma_free_from_pool(NULL, vaddr, bytes)) return; + bytes = mem_cc_align_to_shared_granule(bytes); /* Intentional leak if pages cannot be encrypted again. */ if (!cc_shared || !set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes))) -- 2.43.0