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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 72438C48BE5 for ; Tue, 15 Jun 2021 11:25:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D5BA61455 for ; Tue, 15 Jun 2021 11:25:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230233AbhFOL13 (ORCPT ); Tue, 15 Jun 2021 07:27:29 -0400 Received: from foss.arm.com ([217.140.110.172]:33238 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230225AbhFOL1W (ORCPT ); Tue, 15 Jun 2021 07:27:22 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B511F31B; Tue, 15 Jun 2021 04:25:17 -0700 (PDT) Received: from [10.57.9.136] (unknown [10.57.9.136]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9B1E93F719; Tue, 15 Jun 2021 04:25:16 -0700 (PDT) Subject: Re: [PATCH v3 6/6] iommu/amd: Sync once for scatter-gather operations To: Nadav Amit , Joerg Roedel Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Nadav Amit , Jiajun Cao , Will Deacon References: <20210607182541.119756-1-namit@vmware.com> <20210607182541.119756-7-namit@vmware.com> From: Robin Murphy Message-ID: <99671205-134d-7563-63e2-b65c13d5d074@arm.com> Date: Tue, 15 Jun 2021 12:25:11 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210607182541.119756-7-namit@vmware.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-06-07 19:25, Nadav Amit wrote: > From: Nadav Amit > > On virtual machines, software must flush the IOTLB after each page table > entry update. > > The iommu_map_sg() code iterates through the given scatter-gather list > and invokes iommu_map() for each element in the scatter-gather list, > which calls into the vendor IOMMU driver through iommu_ops callback. As > the result, a single sg mapping may lead to multiple IOTLB flushes. > > Fix this by adding amd_iotlb_sync_map() callback and flushing at this > point after all sg mappings we set. > > This commit is followed and inspired by commit 933fcd01e97e2 > ("iommu/vt-d: Add iotlb_sync_map callback"). > > Cc: Joerg Roedel > Cc: Will Deacon > Cc: Jiajun Cao > Cc: Robin Murphy > Cc: Lu Baolu > Cc: iommu@lists.linux-foundation.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Nadav Amit > --- > drivers/iommu/amd/iommu.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c > index 128f2e889ced..dd23566f1db8 100644 > --- a/drivers/iommu/amd/iommu.c > +++ b/drivers/iommu/amd/iommu.c > @@ -2027,6 +2027,16 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, > return ret; > } > > +static void amd_iommu_iotlb_sync_map(struct iommu_domain *dom, > + unsigned long iova, size_t size) > +{ > + struct protection_domain *domain = to_pdomain(dom); > + struct io_pgtable_ops *ops = &domain->iop.iop.ops; > + > + if (ops->map) Not too critical since you're only moving existing code around, but is ops->map ever not set? Either way the check ends up looking rather out-of-place here :/ It's not very clear what the original intent was - I do wonder whether it's supposed to be related to PAGE_MODE_NONE, but given that amd_iommu_map() has an explicit check and errors out early in that case, we'd never get here anyway. Possibly something to come back and clean up later? Robin. > + domain_flush_np_cache(domain, iova, size); > +} > + > static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, > phys_addr_t paddr, size_t page_size, int iommu_prot, > gfp_t gfp) > @@ -2045,10 +2055,8 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, > if (iommu_prot & IOMMU_WRITE) > prot |= IOMMU_PROT_IW; > > - if (ops->map) { > + if (ops->map) > ret = ops->map(ops, iova, paddr, page_size, prot, gfp); > - domain_flush_np_cache(domain, iova, page_size); > - } > > return ret; > } > @@ -2249,6 +2257,7 @@ const struct iommu_ops amd_iommu_ops = { > .attach_dev = amd_iommu_attach_device, > .detach_dev = amd_iommu_detach_device, > .map = amd_iommu_map, > + .iotlb_sync_map = amd_iommu_iotlb_sync_map, > .unmap = amd_iommu_unmap, > .iova_to_phys = amd_iommu_iova_to_phys, > .probe_device = amd_iommu_probe_device, > 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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 B9809C48BE5 for ; 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Tue, 15 Jun 2021 04:25:17 -0700 (PDT) Received: from [10.57.9.136] (unknown [10.57.9.136]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9B1E93F719; Tue, 15 Jun 2021 04:25:16 -0700 (PDT) Subject: Re: [PATCH v3 6/6] iommu/amd: Sync once for scatter-gather operations To: Nadav Amit , Joerg Roedel References: <20210607182541.119756-1-namit@vmware.com> <20210607182541.119756-7-namit@vmware.com> From: Robin Murphy Message-ID: <99671205-134d-7563-63e2-b65c13d5d074@arm.com> Date: Tue, 15 Jun 2021 12:25:11 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210607182541.119756-7-namit@vmware.com> Content-Language: en-GB Cc: Will Deacon , iommu@lists.linux-foundation.org, Nadav Amit , linux-kernel@vger.kernel.org, Jiajun Cao 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 2021-06-07 19:25, Nadav Amit wrote: > From: Nadav Amit > > On virtual machines, software must flush the IOTLB after each page table > entry update. > > The iommu_map_sg() code iterates through the given scatter-gather list > and invokes iommu_map() for each element in the scatter-gather list, > which calls into the vendor IOMMU driver through iommu_ops callback. As > the result, a single sg mapping may lead to multiple IOTLB flushes. > > Fix this by adding amd_iotlb_sync_map() callback and flushing at this > point after all sg mappings we set. > > This commit is followed and inspired by commit 933fcd01e97e2 > ("iommu/vt-d: Add iotlb_sync_map callback"). > > Cc: Joerg Roedel > Cc: Will Deacon > Cc: Jiajun Cao > Cc: Robin Murphy > Cc: Lu Baolu > Cc: iommu@lists.linux-foundation.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Nadav Amit > --- > drivers/iommu/amd/iommu.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c > index 128f2e889ced..dd23566f1db8 100644 > --- a/drivers/iommu/amd/iommu.c > +++ b/drivers/iommu/amd/iommu.c > @@ -2027,6 +2027,16 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, > return ret; > } > > +static void amd_iommu_iotlb_sync_map(struct iommu_domain *dom, > + unsigned long iova, size_t size) > +{ > + struct protection_domain *domain = to_pdomain(dom); > + struct io_pgtable_ops *ops = &domain->iop.iop.ops; > + > + if (ops->map) Not too critical since you're only moving existing code around, but is ops->map ever not set? Either way the check ends up looking rather out-of-place here :/ It's not very clear what the original intent was - I do wonder whether it's supposed to be related to PAGE_MODE_NONE, but given that amd_iommu_map() has an explicit check and errors out early in that case, we'd never get here anyway. Possibly something to come back and clean up later? Robin. > + domain_flush_np_cache(domain, iova, size); > +} > + > static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, > phys_addr_t paddr, size_t page_size, int iommu_prot, > gfp_t gfp) > @@ -2045,10 +2055,8 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, > if (iommu_prot & IOMMU_WRITE) > prot |= IOMMU_PROT_IW; > > - if (ops->map) { > + if (ops->map) > ret = ops->map(ops, iova, paddr, page_size, prot, gfp); > - domain_flush_np_cache(domain, iova, page_size); > - } > > return ret; > } > @@ -2249,6 +2257,7 @@ const struct iommu_ops amd_iommu_ops = { > .attach_dev = amd_iommu_attach_device, > .detach_dev = amd_iommu_detach_device, > .map = amd_iommu_map, > + .iotlb_sync_map = amd_iommu_iotlb_sync_map, > .unmap = amd_iommu_unmap, > .iova_to_phys = amd_iommu_iova_to_phys, > .probe_device = amd_iommu_probe_device, > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu