From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1BC6C4332F for ; Tue, 15 Mar 2022 06:36:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236290AbiCOGhg (ORCPT ); Tue, 15 Mar 2022 02:37:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235433AbiCOGhf (ORCPT ); Tue, 15 Mar 2022 02:37:35 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E9AD4A3F9; Mon, 14 Mar 2022 23:36:24 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 2BC5468AFE; Tue, 15 Mar 2022 07:36:18 +0100 (CET) Date: Tue, 15 Mar 2022 07:36:18 +0100 From: Christoph Hellwig To: Boris Ostrovsky Cc: Christoph Hellwig , iommu@lists.linux-foundation.org, x86@kernel.org, Anshuman Khandual , Tom Lendacky , Konrad Rzeszutek Wilk , Stefano Stabellini , Juergen Gross , Joerg Roedel , David Woodhouse , Lu Baolu , Robin Murphy , linux-arm-kernel@lists.infradead.org, xen-devel@lists.xenproject.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-hyperv@vger.kernel.org, tboot-devel@lists.sourceforge.net, linux-pci@vger.kernel.org Subject: Re: [PATCH 12/15] swiotlb: provide swiotlb_init variants that remap the buffer Message-ID: <20220315063618.GA1244@lst.de> References: <20220314073129.1862284-1-hch@lst.de> <20220314073129.1862284-13-hch@lst.de> <4d800aa8-5e38-1ad9-284f-1754c83d0f8a@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4d800aa8-5e38-1ad9-284f-1754c83d0f8a@oracle.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Mon, Mar 14, 2022 at 06:39:21PM -0400, Boris Ostrovsky wrote: > This is IO_TLB_MIN_SLABS, isn't it? (Xen code didn't say so but that's what it meant to say I believe) Yes, that makes much more sense. I've switched the patch to use IO_TLB_MIN_SLABS and drop the 2MB comment in both places. Can I get a review with that fixed up? --- >From 153085bf3e6e69d676bef0fb96395a86fb8122f5 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 14 Mar 2022 08:02:57 +0100 Subject: swiotlb: provide swiotlb_init variants that remap the buffer To shared more code between swiotlb and xen-swiotlb, offer a swiotlb_init_remap interface and add a remap callback to swiotlb_init_late that will allow Xen to remap the buffer the buffer without duplicating much of the logic. Signed-off-by: Christoph Hellwig --- arch/x86/pci/sta2x11-fixup.c | 2 +- include/linux/swiotlb.h | 5 ++++- kernel/dma/swiotlb.c | 36 +++++++++++++++++++++++++++++++++--- 3 files changed, 38 insertions(+), 5 deletions(-) diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c index c7e6faf59a861..7368afc039987 100644 --- a/arch/x86/pci/sta2x11-fixup.c +++ b/arch/x86/pci/sta2x11-fixup.c @@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev) int size = STA2X11_SWIOTLB_SIZE; /* First instance: register your own swiotlb area */ dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size); - if (swiotlb_init_late(size, GFP_DMA)) + if (swiotlb_init_late(size, GFP_DMA, NULL)) dev_emerg(&pdev->dev, "init swiotlb failed\n"); } list_add(&instance->list, &sta2x11_instance_list); diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index ee655f2e4d28b..7b50c82f84ce9 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -36,8 +36,11 @@ struct scatterlist; int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, unsigned int flags); unsigned long swiotlb_size_or_default(void); +void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, + int (*remap)(void *tlb, unsigned long nslabs)); +int swiotlb_init_late(size_t size, gfp_t gfp_mask, + int (*remap)(void *tlb, unsigned long nslabs)); extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs); -int swiotlb_init_late(size_t size, gfp_t gfp_mask); extern void __init swiotlb_update_mem_attributes(void); phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys, diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 79641c446d284..b3d4f24fb5f5e 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -256,9 +256,11 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, * Statically reserve bounce buffer space and initialize bounce buffer data * structures for the software IO TLB used to implement the DMA API. */ -void __init swiotlb_init(bool addressing_limit, unsigned int flags) +void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, + int (*remap)(void *tlb, unsigned long nslabs)) { - size_t bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT); + unsigned long nslabs = default_nslabs; + size_t bytes; void *tlb; if (!addressing_limit && !swiotlb_force_bounce) @@ -271,12 +273,23 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags) * allow to pick a location everywhere for hypervisors with guest * memory encryption. */ +retry: + bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT); if (flags & SWIOTLB_ANY) tlb = memblock_alloc(bytes, PAGE_SIZE); else tlb = memblock_alloc_low(bytes, PAGE_SIZE); if (!tlb) goto fail; + if (remap && remap(tlb, nslabs) < 0) { + memblock_free(tlb, PAGE_ALIGN(bytes)); + + if (nslabs <= IO_TLB_MIN_SLABS) + panic("%s: Failed to remap %zu bytes\n", + __func__, bytes); + nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE)); + goto retry; + } if (swiotlb_init_with_tbl(tlb, default_nslabs, flags)) goto fail_free_mem; return; @@ -287,12 +300,18 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags) pr_warn("Cannot allocate buffer"); } +void __init swiotlb_init(bool addressing_limit, unsigned int flags) +{ + return swiotlb_init_remap(addressing_limit, flags, NULL); +} + /* * Systems with larger DMA zones (those that don't support ISA) can * initialize the swiotlb later using the slab allocator if needed. * This should be just like above, but with some error catching. */ -int swiotlb_init_late(size_t size, gfp_t gfp_mask) +int swiotlb_init_late(size_t size, gfp_t gfp_mask, + int (*remap)(void *tlb, unsigned long nslabs)) { unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE); unsigned long bytes; @@ -303,6 +322,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask) if (swiotlb_force_disable) return 0; +retry: order = get_order(nslabs << IO_TLB_SHIFT); nslabs = SLABS_PER_PAGE << order; bytes = nslabs << IO_TLB_SHIFT; @@ -317,6 +337,16 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask) if (!vstart) return -ENOMEM; + if (remap) + rc = remap(vstart, nslabs); + if (rc) { + free_pages((unsigned long)vstart, order); + + if (IO_TLB_MIN_SLABS <= 1024) + return rc; + nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE)); + goto retry; + } if (order != get_order(bytes)) { pr_warn("only able to allocate %ld MB\n", -- 2.30.2