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 X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59DB3C433B4 for ; Tue, 20 Apr 2021 09:23:40 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 56F1261164 for ; Tue, 20 Apr 2021 09:23:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 56F1261164 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FPdXT6PY5z304X for ; Tue, 20 Apr 2021 19:23:37 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FPdX64FwVz2xZW for ; Tue, 20 Apr 2021 19:23:17 +1000 (AEST) Received: by verein.lst.de (Postfix, from userid 2407) id 59ECA68C4E; Tue, 20 Apr 2021 11:23:12 +0200 (CEST) Date: Tue, 20 Apr 2021 11:23:12 +0200 From: Christoph Hellwig To: Tom Lendacky Subject: Re: swiotlb cleanups v3 Message-ID: <20210420092312.GB26092@lst.de> References: <20210318161424.489045-1-hch@lst.de> <0349082c-59c5-20d7-f324-279981c3f6ea@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0349082c-59c5-20d7-f324-279981c3f6ea@amd.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: xen-devel@lists.xenproject.org, konrad.wilk@oracle.com, iommu@lists.linux-foundation.org, dongli.zhang@oracle.com, tientzu@chromium.org, linuxppc-dev@lists.ozlabs.org, hch@lst.de Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, Apr 17, 2021 at 11:39:22AM -0500, Tom Lendacky wrote: > Somewhere between the 1st and 2nd patch, specifying a specific swiotlb > for an SEV guest is no longer honored. For example, if I start an SEV > guest with 16GB of memory and specify swiotlb=131072 I used to get a > 256MB SWIOTLB. However, after the 2nd patch, the swiotlb=131072 is no > longer honored and I get a 982MB SWIOTLB (as set via sev_setup_arch() in > arch/x86/mm/mem_encrypt.c). > > I can't be sure which patch caused the issue since an SEV guest fails to > boot with the 1st patch but can boot with the 2nd patch, at which point > the SWIOTLB comes in at 982MB (I haven't had a chance to debug it and so > I'm hoping you might be able to quickly spot what's going on). Can you try this patch? diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 0a5b6f7e75bce6..ac81ef97df32f5 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -71,15 +71,17 @@ struct io_tlb_mem *io_tlb_default_mem; */ static unsigned int max_segment; -static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT; +static unsigned long swiotlb_cmdline_size; static int __init setup_io_tlb_npages(char *str) { if (isdigit(*str)) { /* avoid tail segment of size < IO_TLB_SEGSIZE */ - default_nslabs = - ALIGN(simple_strtoul(str, &str, 0), IO_TLB_SEGSIZE); + unsigned long nslabs = simple_strtoul(str, &str, 0); + + swiotlb_cmdline_size = + ALIGN(nslabs, IO_TLB_SEGSIZE) << IO_TLB_SHIFT; } if (*str == ',') ++str; @@ -108,7 +110,9 @@ void swiotlb_set_max_segment(unsigned int val) unsigned long swiotlb_size_or_default(void) { - return default_nslabs << IO_TLB_SHIFT; + if (swiotlb_cmdline_size) + return swiotlb_cmdline_size; + return IO_TLB_DEFAULT_SIZE; } void __init swiotlb_adjust_size(unsigned long size) @@ -118,9 +122,10 @@ void __init swiotlb_adjust_size(unsigned long size) * architectures such as those supporting memory encryption to * adjust/expand SWIOTLB size for their use. */ - size = ALIGN(size, IO_TLB_SIZE); - default_nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE); - pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 20); + if (!swiotlb_cmdline_size) + swiotlb_cmdline_size = ALIGN(size, IO_TLB_SIZE); + pr_info("SWIOTLB bounce buffer size adjusted to %luMB", + swiotlb_cmdline_size >> 20); } void swiotlb_print_info(void) @@ -209,7 +214,7 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) void __init swiotlb_init(int verbose) { - size_t bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT); + size_t bytes = PAGE_ALIGN(swiotlb_size_or_default()); void *tlb; if (swiotlb_force == SWIOTLB_NO_FORCE) @@ -219,7 +224,7 @@ swiotlb_init(int verbose) tlb = memblock_alloc_low(bytes, PAGE_SIZE); if (!tlb) goto fail; - if (swiotlb_init_with_tbl(tlb, default_nslabs, verbose)) + if (swiotlb_init_with_tbl(tlb, bytes >> IO_TLB_SHIFT, verbose)) goto fail_free_mem; return;