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=-11.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,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 7BD95C4741F for ; Thu, 5 Nov 2020 17:42:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0253020709 for ; Thu, 5 Nov 2020 17:42:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="jOi3adrS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731620AbgKERmP (ORCPT ); Thu, 5 Nov 2020 12:42:15 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:47772 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725862AbgKERmP (ORCPT ); Thu, 5 Nov 2020 12:42:15 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0A5HQ7RE171926; Thu, 5 Nov 2020 17:41:44 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=Ygi5p2ytGYAOiTFCHa1IHIsoZmRXyEeKJ2onczmmk74=; b=jOi3adrSO9KNBupAJ7S4VihrMXGCDX9J5BpMBrLFGkwuyCDsq3WVf1drkDIKmERTAg1B s55DojrdLb0f7uZgn2zhd9G35SmBpqlzXyvPONt5ijA2I4aaf9nYIIm16EJzlhL38CrP nmm1T0gHph6CYMGotzry7GsB8VuQF6L1C1/78IOeZ6UeZtTq2yrdDmogqxbcHjkcZd49 JHJmBKfd6EJ0+y2Ev1iFzZQoeFID3I8/X+sx0XbvHdmbCchN++sUIq5P6B99lO3PYlcX iLYsaRyFZW4FKF3FLtiI09zwnsMaE9TcgzLYKNaePuRCDQ4fXcm7I9ihdG0eO4pHQgmU AQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by aserp2120.oracle.com with ESMTP id 34hhvcn7qj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 05 Nov 2020 17:41:44 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0A5HPDok109474; Thu, 5 Nov 2020 17:41:44 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 34jf4chq16-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 05 Nov 2020 17:41:44 +0000 Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 0A5HfTSv016553; Thu, 5 Nov 2020 17:41:34 GMT Received: from char.us.oracle.com (/10.152.32.25) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 05 Nov 2020 09:41:29 -0800 Received: by char.us.oracle.com (Postfix, from userid 1000) id C23D96A00F1; Thu, 5 Nov 2020 12:43:17 -0500 (EST) Date: Thu, 5 Nov 2020 12:43:17 -0500 From: Konrad Rzeszutek Wilk To: Ashish Kalra Cc: hch@lst.de, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, luto@kernel.org, peterz@infradead.org, dave.hansen@linux-intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, brijesh.singh@amd.com, Thomas.Lendacky@amd.com, ssg.sos.patches@amd.com Subject: Re: [PATCH v3] swiotlb: Adjust SWIOTBL bounce buffer size for SEV guests. Message-ID: <20201105174317.GA4294@char.us.oracle.com> References: <20201104220804.21026-1-Ashish.Kalra@amd.com> <20201104221452.GA26079@char.us.oracle.com> <20201104223913.GA25311@ashkalra_ubuntu_server> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201104223913.GA25311@ashkalra_ubuntu_server> User-Agent: Mutt/1.9.1 (2017-09-22) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9796 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 mlxscore=0 bulkscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011050114 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9796 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 impostorscore=0 malwarescore=0 priorityscore=1501 mlxlogscore=999 bulkscore=0 phishscore=0 adultscore=0 mlxscore=0 lowpriorityscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011050114 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 04, 2020 at 10:39:13PM +0000, Ashish Kalra wrote: > Hello Konrad, > > On Wed, Nov 04, 2020 at 05:14:52PM -0500, Konrad Rzeszutek Wilk wrote: > > On Wed, Nov 04, 2020 at 10:08:04PM +0000, Ashish Kalra wrote: > > > From: Ashish Kalra > > > > > > For SEV, all DMA to and from guest has to use shared > > > (un-encrypted) pages. SEV uses SWIOTLB to make this > > > happen without requiring changes to device drivers. > > > However, depending on workload being run, the default > > > 64MB of SWIOTLB might not be enough and SWIOTLB > > > may run out of buffers to use for DMA, resulting > > > in I/O errors and/or performance degradation for > > > high I/O workloads. > > > > > > Increase the default size of SWIOTLB for SEV guests > > > using a minimum value of 128MB and a maximum value > > > > > > > > 64MB for a 1GB VM is not enough? > > > > > of 512MB, determining on amount of provisioned guest > > > > I like the implementation on how this is done.. but > > the choices of memory and how much seems very much > > random. Could there be some math behind this? > > > > Earlier the patch was based on using a % of guest memory, as below: > > +#define SEV_ADJUST_SWIOTLB_SIZE_PERCENT 5 > +#define SEV_ADJUST_SWIOTLB_SIZE_MAX (1UL << 30) > ... > ... > + if (sev_active() && !io_tlb_nslabs) { > + unsigned long total_mem = get_num_physpages() << PAGE_SHIFT; > + > + default_size = total_mem * > + SEV_ADJUST_SWIOTLB_SIZE_PERCENT / 100; > + > + default_size = ALIGN(default_size, 1 << IO_TLB_SHIFT); > + > + default_size = clamp_val(default_size, IO_TLB_DEFAULT_SIZE, > + SEV_ADJUST_SWIOTLB_SIZE_MAX); > + } > > But, then it is difficult to predict what % of guest memory to use ? > > Then there are other factors to consider, such as vcpu_count or if there > is going to be high I/O workload, etc. > > But that all makes it very complicated, what we basically want is a > range from 128M to 512M and that's why the current patch which picks up > this range from the amount of allocated guest memory keeps it simple. Right, so I am wondering if we can do this better. That is you are never going to get any 32-bit devices with SEV right? That is there is nothing that bounds you to always use the memory below 4GB? What I wonder is if we can combine the boot-allocation of the SWIOTLB with the post-boot-allocation of SWIOLTB to stitch together continous physical ranges. That way you have the flexibility at the start of using 64MB but if there is pressure, we grow to a bigger size? > > Thanks, > Ashish > > > > memory. > > > > > > Using late_initcall() interface to invoke > > > swiotlb_adjust() does not work as the size > > > adjustment needs to be done before mem_encrypt_init() > > > and reserve_crashkernel() which use the allocated > > > SWIOTLB buffer size, hence calling it explicitly > > > from setup_arch(). > > > > > > The SWIOTLB default size adjustment is added as an > > > architecture specific interface/callback to allow > > > architectures such as those supporting memory > > > encryption to adjust/expand SWIOTLB size for their > > > use. > > > > > > Signed-off-by: Ashish Kalra > > > --- > > > arch/x86/kernel/setup.c | 2 ++ > > > arch/x86/mm/mem_encrypt.c | 42 +++++++++++++++++++++++++++++++++++++++ > > > include/linux/swiotlb.h | 1 + > > > kernel/dma/swiotlb.c | 27 +++++++++++++++++++++++++ > > > 4 files changed, 72 insertions(+) > > > > > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > > > index 3511736fbc74..b073d58dd4a3 100644 > > > --- a/arch/x86/kernel/setup.c > > > +++ b/arch/x86/kernel/setup.c > > > @@ -1166,6 +1166,8 @@ void __init setup_arch(char **cmdline_p) > > > if (boot_cpu_has(X86_FEATURE_GBPAGES)) > > > hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT); > > > > > > + swiotlb_adjust(); > > > + > > > /* > > > * Reserve memory for crash kernel after SRAT is parsed so that it > > > * won't consume hotpluggable memory. > > > diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c > > > index 3f248f0d0e07..e0deb157cddd 100644 > > > --- a/arch/x86/mm/mem_encrypt.c > > > +++ b/arch/x86/mm/mem_encrypt.c > > > @@ -489,7 +489,49 @@ static void print_mem_encrypt_feature_info(void) > > > pr_cont("\n"); > > > } > > > > > > +#define TOTAL_MEM_1G 0x40000000UL > > > +#define TOTAL_MEM_4G 0x100000000UL > > > + > > > +#define SIZE_128M (128UL<<20) > > > +#define SIZE_256M (256UL<<20) > > > +#define SIZE_512M (512UL<<20) > > > + > > > /* Architecture __weak replacement functions */ > > > +unsigned long __init arch_swiotlb_adjust(unsigned long iotlb_default_size) > > > +{ > > > + unsigned long size = 0; > > > + > > > + /* > > > + * For SEV, all DMA has to occur via shared/unencrypted pages. > > > + * SEV uses SWOTLB to make this happen without changing device > > > + * drivers. However, depending on the workload being run, the > > > + * default 64MB of SWIOTLB may not be enough & SWIOTLB may > > > + * run out of buffers for DMA, resulting in I/O errors and/or > > > + * performance degradation especially with high I/O workloads. > > > + * Increase the default size of SWIOTLB for SEV guests using > > > + * a minimum value of 128MB and a maximum value of 512MB, > > > + * depending on amount of provisioned guest memory. > > > + */ > > > + if (sev_active()) { > > > + phys_addr_t total_mem = memblock_phys_mem_size(); > > > + > > > + if (total_mem <= TOTAL_MEM_1G) > > > + size = clamp(iotlb_default_size * 2, SIZE_128M, > > > + SIZE_128M); > > > + else if (total_mem <= TOTAL_MEM_4G) > > > + size = clamp(iotlb_default_size * 4, SIZE_256M, > > > + SIZE_256M); > > > + else > > > + size = clamp(iotlb_default_size * 8, SIZE_512M, > > > + SIZE_512M); > > > + > > > + pr_info("SEV adjusted max SWIOTLB size = %luMB", > > > + size >> 20); > > > + } > > > + > > > + return size; > > > +} > > > + > > > void __init mem_encrypt_init(void) > > > { > > > if (!sme_me_mask) > > > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > > > index 046bb94bd4d6..01ae6d891327 100644 > > > --- a/include/linux/swiotlb.h > > > +++ b/include/linux/swiotlb.h > > > @@ -33,6 +33,7 @@ extern void swiotlb_init(int verbose); > > > int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose); > > > extern unsigned long swiotlb_nr_tbl(void); > > > unsigned long swiotlb_size_or_default(void); > > > +extern void __init swiotlb_adjust(void); > > > extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs); > > > extern void __init swiotlb_update_mem_attributes(void); > > > > > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > > > index c19379fabd20..66a9e627bb51 100644 > > > --- a/kernel/dma/swiotlb.c > > > +++ b/kernel/dma/swiotlb.c > > > @@ -163,6 +163,33 @@ unsigned long swiotlb_size_or_default(void) > > > return size ? size : (IO_TLB_DEFAULT_SIZE); > > > } > > > > > > +unsigned long __init __weak arch_swiotlb_adjust(unsigned long size) > > > +{ > > > + return 0; > > > +} > > > + > > > +void __init swiotlb_adjust(void) > > > +{ > > > + unsigned long size; > > > + > > > + /* > > > + * If swiotlb parameter has not been specified, give a chance to > > > + * architectures such as those supporting memory encryption to > > > + * adjust/expand SWIOTLB size for their use. > > > + */ > > > + if (!io_tlb_nslabs) { > > > + size = arch_swiotlb_adjust(IO_TLB_DEFAULT_SIZE); > > > + if (size) { > > > + size = ALIGN(size, 1 << IO_TLB_SHIFT); > > > + io_tlb_nslabs = size >> IO_TLB_SHIFT; > > > + io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); > > > + > > > + pr_info("architecture adjusted SWIOTLB slabs = %lu\n", > > > + io_tlb_nslabs); > > > + } > > > + } > > > +} > > > + > > > void swiotlb_print_info(void) > > > { > > > unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT; > > > -- > > > 2.17.1 > > > 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=-11.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 3AC26C4741F for ; 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Thu, 5 Nov 2020 17:41:44 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 34jf4chq16-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 05 Nov 2020 17:41:44 +0000 Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 0A5HfTSv016553; Thu, 5 Nov 2020 17:41:34 GMT Received: from char.us.oracle.com (/10.152.32.25) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 05 Nov 2020 09:41:29 -0800 Received: by char.us.oracle.com (Postfix, from userid 1000) id C23D96A00F1; Thu, 5 Nov 2020 12:43:17 -0500 (EST) Date: Thu, 5 Nov 2020 12:43:17 -0500 From: Konrad Rzeszutek Wilk To: Ashish Kalra Subject: Re: [PATCH v3] swiotlb: Adjust SWIOTBL bounce buffer size for SEV guests. Message-ID: <20201105174317.GA4294@char.us.oracle.com> References: <20201104220804.21026-1-Ashish.Kalra@amd.com> <20201104221452.GA26079@char.us.oracle.com> <20201104223913.GA25311@ashkalra_ubuntu_server> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201104223913.GA25311@ashkalra_ubuntu_server> User-Agent: Mutt/1.9.1 (2017-09-22) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9796 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 mlxscore=0 bulkscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011050114 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9796 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 impostorscore=0 malwarescore=0 priorityscore=1501 mlxlogscore=999 bulkscore=0 phishscore=0 adultscore=0 mlxscore=0 lowpriorityscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011050114 Cc: Thomas.Lendacky@amd.com, brijesh.singh@amd.com, ssg.sos.patches@amd.com, dave.hansen@linux-intel.com, peterz@infradead.org, x86@kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, mingo@redhat.com, bp@alien8.de, luto@kernel.org, hpa@zytor.com, tglx@linutronix.de, hch@lst.de X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Wed, Nov 04, 2020 at 10:39:13PM +0000, Ashish Kalra wrote: > Hello Konrad, > > On Wed, Nov 04, 2020 at 05:14:52PM -0500, Konrad Rzeszutek Wilk wrote: > > On Wed, Nov 04, 2020 at 10:08:04PM +0000, Ashish Kalra wrote: > > > From: Ashish Kalra > > > > > > For SEV, all DMA to and from guest has to use shared > > > (un-encrypted) pages. SEV uses SWIOTLB to make this > > > happen without requiring changes to device drivers. > > > However, depending on workload being run, the default > > > 64MB of SWIOTLB might not be enough and SWIOTLB > > > may run out of buffers to use for DMA, resulting > > > in I/O errors and/or performance degradation for > > > high I/O workloads. > > > > > > Increase the default size of SWIOTLB for SEV guests > > > using a minimum value of 128MB and a maximum value > > > > > > > > 64MB for a 1GB VM is not enough? > > > > > of 512MB, determining on amount of provisioned guest > > > > I like the implementation on how this is done.. but > > the choices of memory and how much seems very much > > random. Could there be some math behind this? > > > > Earlier the patch was based on using a % of guest memory, as below: > > +#define SEV_ADJUST_SWIOTLB_SIZE_PERCENT 5 > +#define SEV_ADJUST_SWIOTLB_SIZE_MAX (1UL << 30) > ... > ... > + if (sev_active() && !io_tlb_nslabs) { > + unsigned long total_mem = get_num_physpages() << PAGE_SHIFT; > + > + default_size = total_mem * > + SEV_ADJUST_SWIOTLB_SIZE_PERCENT / 100; > + > + default_size = ALIGN(default_size, 1 << IO_TLB_SHIFT); > + > + default_size = clamp_val(default_size, IO_TLB_DEFAULT_SIZE, > + SEV_ADJUST_SWIOTLB_SIZE_MAX); > + } > > But, then it is difficult to predict what % of guest memory to use ? > > Then there are other factors to consider, such as vcpu_count or if there > is going to be high I/O workload, etc. > > But that all makes it very complicated, what we basically want is a > range from 128M to 512M and that's why the current patch which picks up > this range from the amount of allocated guest memory keeps it simple. Right, so I am wondering if we can do this better. That is you are never going to get any 32-bit devices with SEV right? That is there is nothing that bounds you to always use the memory below 4GB? What I wonder is if we can combine the boot-allocation of the SWIOTLB with the post-boot-allocation of SWIOLTB to stitch together continous physical ranges. That way you have the flexibility at the start of using 64MB but if there is pressure, we grow to a bigger size? > > Thanks, > Ashish > > > > memory. > > > > > > Using late_initcall() interface to invoke > > > swiotlb_adjust() does not work as the size > > > adjustment needs to be done before mem_encrypt_init() > > > and reserve_crashkernel() which use the allocated > > > SWIOTLB buffer size, hence calling it explicitly > > > from setup_arch(). > > > > > > The SWIOTLB default size adjustment is added as an > > > architecture specific interface/callback to allow > > > architectures such as those supporting memory > > > encryption to adjust/expand SWIOTLB size for their > > > use. > > > > > > Signed-off-by: Ashish Kalra > > > --- > > > arch/x86/kernel/setup.c | 2 ++ > > > arch/x86/mm/mem_encrypt.c | 42 +++++++++++++++++++++++++++++++++++++++ > > > include/linux/swiotlb.h | 1 + > > > kernel/dma/swiotlb.c | 27 +++++++++++++++++++++++++ > > > 4 files changed, 72 insertions(+) > > > > > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > > > index 3511736fbc74..b073d58dd4a3 100644 > > > --- a/arch/x86/kernel/setup.c > > > +++ b/arch/x86/kernel/setup.c > > > @@ -1166,6 +1166,8 @@ void __init setup_arch(char **cmdline_p) > > > if (boot_cpu_has(X86_FEATURE_GBPAGES)) > > > hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT); > > > > > > + swiotlb_adjust(); > > > + > > > /* > > > * Reserve memory for crash kernel after SRAT is parsed so that it > > > * won't consume hotpluggable memory. > > > diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c > > > index 3f248f0d0e07..e0deb157cddd 100644 > > > --- a/arch/x86/mm/mem_encrypt.c > > > +++ b/arch/x86/mm/mem_encrypt.c > > > @@ -489,7 +489,49 @@ static void print_mem_encrypt_feature_info(void) > > > pr_cont("\n"); > > > } > > > > > > +#define TOTAL_MEM_1G 0x40000000UL > > > +#define TOTAL_MEM_4G 0x100000000UL > > > + > > > +#define SIZE_128M (128UL<<20) > > > +#define SIZE_256M (256UL<<20) > > > +#define SIZE_512M (512UL<<20) > > > + > > > /* Architecture __weak replacement functions */ > > > +unsigned long __init arch_swiotlb_adjust(unsigned long iotlb_default_size) > > > +{ > > > + unsigned long size = 0; > > > + > > > + /* > > > + * For SEV, all DMA has to occur via shared/unencrypted pages. > > > + * SEV uses SWOTLB to make this happen without changing device > > > + * drivers. However, depending on the workload being run, the > > > + * default 64MB of SWIOTLB may not be enough & SWIOTLB may > > > + * run out of buffers for DMA, resulting in I/O errors and/or > > > + * performance degradation especially with high I/O workloads. > > > + * Increase the default size of SWIOTLB for SEV guests using > > > + * a minimum value of 128MB and a maximum value of 512MB, > > > + * depending on amount of provisioned guest memory. > > > + */ > > > + if (sev_active()) { > > > + phys_addr_t total_mem = memblock_phys_mem_size(); > > > + > > > + if (total_mem <= TOTAL_MEM_1G) > > > + size = clamp(iotlb_default_size * 2, SIZE_128M, > > > + SIZE_128M); > > > + else if (total_mem <= TOTAL_MEM_4G) > > > + size = clamp(iotlb_default_size * 4, SIZE_256M, > > > + SIZE_256M); > > > + else > > > + size = clamp(iotlb_default_size * 8, SIZE_512M, > > > + SIZE_512M); > > > + > > > + pr_info("SEV adjusted max SWIOTLB size = %luMB", > > > + size >> 20); > > > + } > > > + > > > + return size; > > > +} > > > + > > > void __init mem_encrypt_init(void) > > > { > > > if (!sme_me_mask) > > > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > > > index 046bb94bd4d6..01ae6d891327 100644 > > > --- a/include/linux/swiotlb.h > > > +++ b/include/linux/swiotlb.h > > > @@ -33,6 +33,7 @@ extern void swiotlb_init(int verbose); > > > int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose); > > > extern unsigned long swiotlb_nr_tbl(void); > > > unsigned long swiotlb_size_or_default(void); > > > +extern void __init swiotlb_adjust(void); > > > extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs); > > > extern void __init swiotlb_update_mem_attributes(void); > > > > > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > > > index c19379fabd20..66a9e627bb51 100644 > > > --- a/kernel/dma/swiotlb.c > > > +++ b/kernel/dma/swiotlb.c > > > @@ -163,6 +163,33 @@ unsigned long swiotlb_size_or_default(void) > > > return size ? size : (IO_TLB_DEFAULT_SIZE); > > > } > > > > > > +unsigned long __init __weak arch_swiotlb_adjust(unsigned long size) > > > +{ > > > + return 0; > > > +} > > > + > > > +void __init swiotlb_adjust(void) > > > +{ > > > + unsigned long size; > > > + > > > + /* > > > + * If swiotlb parameter has not been specified, give a chance to > > > + * architectures such as those supporting memory encryption to > > > + * adjust/expand SWIOTLB size for their use. > > > + */ > > > + if (!io_tlb_nslabs) { > > > + size = arch_swiotlb_adjust(IO_TLB_DEFAULT_SIZE); > > > + if (size) { > > > + size = ALIGN(size, 1 << IO_TLB_SHIFT); > > > + io_tlb_nslabs = size >> IO_TLB_SHIFT; > > > + io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); > > > + > > > + pr_info("architecture adjusted SWIOTLB slabs = %lu\n", > > > + io_tlb_nslabs); > > > + } > > > + } > > > +} > > > + > > > void swiotlb_print_info(void) > > > { > > > unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT; > > > -- > > > 2.17.1 > > > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu