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=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 786ACC43463 for ; Fri, 18 Sep 2020 13:09:30 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 EA5E0235FD for ; Fri, 18 Sep 2020 13:09:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA5E0235FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=Huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 891812E191; Fri, 18 Sep 2020 13:09:29 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id jgHrviLNP0rl; Fri, 18 Sep 2020 13:09:27 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id 61A512045B; Fri, 18 Sep 2020 13:09:27 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 520BAC0859; Fri, 18 Sep 2020 13:09:27 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id B0322C0051 for ; Fri, 18 Sep 2020 13:09:26 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 9846C8531D for ; Fri, 18 Sep 2020 13:09:26 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pX_1Ej5SycDo for ; Fri, 18 Sep 2020 13:09:25 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from huawei.com (lhrrgout.huawei.com [185.176.76.210]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 2BED285319 for ; Fri, 18 Sep 2020 13:09:25 +0000 (UTC) Received: from lhreml710-chm.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id 4C4B6DF79AB68529DC49; Fri, 18 Sep 2020 14:09:22 +0100 (IST) Received: from localhost (10.52.125.116) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Fri, 18 Sep 2020 14:09:21 +0100 Date: Fri, 18 Sep 2020 14:07:43 +0100 From: Jonathan Cameron To: Jean-Philippe Brucker Subject: Re: [PATCH v10 09/13] iommu/arm-smmu-v3: Seize private ASID Message-ID: <20200918140743.00007482@Huawei.com> In-Reply-To: <20200918101852.582559-10-jean-philippe@linaro.org> References: <20200918101852.582559-1-jean-philippe@linaro.org> <20200918101852.582559-10-jean-philippe@linaro.org> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 X-Originating-IP: [10.52.125.116] X-ClientProxiedBy: lhreml741-chm.china.huawei.com (10.201.108.191) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Cc: fenghua.yu@intel.com, catalin.marinas@arm.com, robin.murphy@arm.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org, zhangfei.gao@linaro.org, will@kernel.org, linux-arm-kernel@lists.infradead.org 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 Fri, 18 Sep 2020 12:18:49 +0200 Jean-Philippe Brucker wrote: > The SMMU has a single ASID space, the union of shared and private ASID > sets. This means that the SMMU driver competes with the arch allocator > for ASIDs. Shared ASIDs are those of Linux processes, allocated by the > arch, and contribute in broadcast TLB maintenance. Private ASIDs are > allocated by the SMMU driver and used for "classic" map/unmap DMA. They > require command-queue TLB invalidations. > > When we pin down an mm_context and get an ASID that is already in use by > the SMMU, it belongs to a private context. We used to simply abort the > bind, but this is unfair to users that would be unable to bind a few > seemingly random processes. Try to allocate a new private ASID for the > context, and make the old ASID shared. > > Signed-off-by: Jean-Philippe Brucker Hi, One totally trivial comment inline that might have ever so slightly improved reviewability of the patch. However it is only minor so don't bother respinning for that. Thanks, Jonathan > --- > v10: fix ASID limit, small comment update > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 3 ++ > .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 35 +++++++++++++++++-- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 34 +++++++++++------- > 3 files changed, 57 insertions(+), 15 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h > index 6b06a6f19604..90c08f156b43 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h > @@ -678,6 +678,9 @@ struct arm_smmu_domain { > extern struct xarray arm_smmu_asid_xa; > extern struct mutex arm_smmu_asid_lock; > > +int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid, > + struct arm_smmu_ctx_desc *cd); > +void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid); > bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd); > > #endif /* _ARM_SMMU_V3_H */ > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c > index 6c1113059632..ef3fcfa72187 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c > @@ -10,10 +10,18 @@ > #include "arm-smmu-v3.h" > #include "../../io-pgtable-arm.h" > > +/* > + * Check if the CPU ASID is available on the SMMU side. If a private context > + * descriptor is using it, try to replace it. > + */ > static struct arm_smmu_ctx_desc * > arm_smmu_share_asid(struct mm_struct *mm, u16 asid) > { > + int ret; > + u32 new_asid; > struct arm_smmu_ctx_desc *cd; > + struct arm_smmu_device *smmu; > + struct arm_smmu_domain *smmu_domain; > > cd = xa_load(&arm_smmu_asid_xa, asid); > if (!cd) > @@ -27,8 +35,31 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid) > return cd; > } > > - /* Ouch, ASID is already in use for a private cd. */ > - return ERR_PTR(-EBUSY); > + smmu_domain = container_of(cd, struct arm_smmu_domain, s1_cfg.cd); > + smmu = smmu_domain->smmu; > + > + ret = xa_alloc(&arm_smmu_asid_xa, &new_asid, cd, > + XA_LIMIT(1, (1 << smmu->asid_bits) - 1), GFP_KERNEL); > + if (ret) > + return ERR_PTR(-ENOSPC); > + /* > + * Race with unmap: TLB invalidations will start targeting the new ASID, > + * which isn't assigned yet. We'll do an invalidate-all on the old ASID > + * later, so it doesn't matter. > + */ > + cd->asid = new_asid; > + /* > + * Update ASID and invalidate CD in all associated masters. There will > + * be some overlap between use of both ASIDs, until we invalidate the > + * TLB. > + */ > + arm_smmu_write_ctx_desc(smmu_domain, 0, cd); > + > + /* Invalidate TLB entries previously associated with that context */ > + arm_smmu_tlb_inv_asid(smmu, asid); > + > + xa_erase(&arm_smmu_asid_xa, asid); > + return NULL; > } > > __maybe_unused > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > index 19af27fd183b..e99ebdd4c841 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > @@ -872,6 +872,17 @@ static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu, > } > > /* Context descriptor manipulation functions */ > +void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid) > +{ > + struct arm_smmu_cmdq_ent cmd = { > + .opcode = CMDQ_OP_TLBI_NH_ASID, > + .tlbi.asid = asid, > + }; > + > + arm_smmu_cmdq_issue_cmd(smmu, &cmd); > + arm_smmu_cmdq_issue_sync(smmu); > +} > + > static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain, > int ssid, bool leaf) > { > @@ -952,8 +963,8 @@ static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_domain *smmu_domain, > return l1_desc->l2ptr + idx * CTXDESC_CD_DWORDS; > } > > -static int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, > - int ssid, struct arm_smmu_ctx_desc *cd) > +int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid, > + struct arm_smmu_ctx_desc *cd) > { > /* > * This function handles the following cases: > @@ -1609,15 +1620,6 @@ static void arm_smmu_tlb_inv_context(void *cookie) > struct arm_smmu_device *smmu = smmu_domain->smmu; > struct arm_smmu_cmdq_ent cmd; > > - if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) { > - cmd.opcode = CMDQ_OP_TLBI_NH_ASID; > - cmd.tlbi.asid = smmu_domain->s1_cfg.cd.asid; > - cmd.tlbi.vmid = 0; > - } else { > - cmd.opcode = CMDQ_OP_TLBI_S12_VMALL; > - cmd.tlbi.vmid = smmu_domain->s2_cfg.vmid; > - } > - > /* > * NOTE: when io-pgtable is in non-strict mode, we may get here with > * PTEs previously cleared by unmaps on the current CPU not yet visible > @@ -1625,8 +1627,14 @@ static void arm_smmu_tlb_inv_context(void *cookie) > * insertion to guarantee those are observed before the TLBI. Do be > * careful, 007. > */ > - arm_smmu_cmdq_issue_cmd(smmu, &cmd); > - arm_smmu_cmdq_issue_sync(smmu); > + if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) { > + arm_smmu_tlb_inv_asid(smmu, smmu_domain->s1_cfg.cd.asid); > + } else { > + cmd.opcode = CMDQ_OP_TLBI_S12_VMALL; > + cmd.tlbi.vmid = smmu_domain->s2_cfg.vmid; > + arm_smmu_cmdq_issue_cmd(smmu, &cmd); > + arm_smmu_cmdq_issue_sync(smmu); > + } Nothing wrong with the code, but you could perhaps have split out the noop refactoring change from more interesting parts. > arm_smmu_atc_inv_domain(smmu_domain, 0, 0, 0); > } > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu