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Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH v5 07/12] arm-smmu-v3/sva: Add SVA domain support Content-Language: en-US To: Jean-Philippe Brucker Cc: Joerg Roedel , Jason Gunthorpe , Christoph Hellwig , Kevin Tian , Ashok Raj , Will Deacon , Robin Murphy , Jean-Philippe Brucker , Dave Jiang , Vinod Koul , Eric Auger , Liu Yi L , Jacob jun Pan , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20220502014842.991097-1-baolu.lu@linux.intel.com> <20220502014842.991097-8-baolu.lu@linux.intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/5/4 02:12, Jean-Philippe Brucker wrote: > On Mon, May 02, 2022 at 09:48:37AM +0800, Lu Baolu wrote: >> Add support for SVA domain allocation and provide an SVA-specific >> iommu_domain_ops. >> >> Signed-off-by: Lu Baolu >> --- >> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 14 +++++++ >> .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 42 +++++++++++++++++++ >> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 21 ++++++++++ >> 3 files changed, 77 insertions(+) >> >> 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 cd48590ada30..7631c00fdcbd 100644 >> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h >> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h >> @@ -759,6 +759,10 @@ struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, >> void arm_smmu_sva_unbind(struct iommu_sva *handle); >> u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle); >> void arm_smmu_sva_notifier_synchronize(void); >> +int arm_smmu_sva_attach_dev_pasid(struct iommu_domain *domain, >> + struct device *dev, ioasid_t id); >> +void arm_smmu_sva_detach_dev_pasid(struct iommu_domain *domain, >> + struct device *dev, ioasid_t id); >> #else /* CONFIG_ARM_SMMU_V3_SVA */ >> static inline bool arm_smmu_sva_supported(struct arm_smmu_device *smmu) >> { >> @@ -804,5 +808,15 @@ static inline u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle) >> } >> >> static inline void arm_smmu_sva_notifier_synchronize(void) {} >> + >> +static inline int arm_smmu_sva_attach_dev_pasid(struct iommu_domain *domain, >> + struct device *dev, ioasid_t id) >> +{ >> + return -ENODEV; >> +} >> + >> +static inline void arm_smmu_sva_detach_dev_pasid(struct iommu_domain *domain, >> + struct device *dev, >> + ioasid_t id) {} >> #endif /* CONFIG_ARM_SMMU_V3_SVA */ >> #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 c623dae1e115..3b843cd3ed67 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 >> @@ -541,3 +541,45 @@ void arm_smmu_sva_notifier_synchronize(void) >> */ >> mmu_notifier_synchronize(); >> } >> + >> +int arm_smmu_sva_attach_dev_pasid(struct iommu_domain *domain, >> + struct device *dev, ioasid_t id) >> +{ >> + int ret = 0; >> + struct iommu_sva *handle; >> + struct mm_struct *mm = iommu_sva_domain_mm(domain); >> + >> + if (domain->type != IOMMU_DOMAIN_SVA || !mm) > > We wouldn't get that far with a non-SVA domain since iommu_sva_domain_mm() > would dereference a NULL pointer. Could you move it after the domain->type > check, and maybe add a WARN_ON()? It could help catch issues in future > API changes. Sure. I will make it like this, int arm_smmu_sva_attach_dev_pasid(struct iommu_domain *domain, struct device *dev, ioasid_t id) { int ret = 0; struct mm_struct *mm; struct iommu_sva *handle; if (domain->type != IOMMU_DOMAIN_SVA) return -EINVAL; mm = iommu_sva_domain_mm(domain); if (WARN_ON(!mm)) return -ENODEV; ... ... > >> + return -EINVAL; >> + >> + mutex_lock(&sva_lock); >> + handle = __arm_smmu_sva_bind(dev, mm); >> + if (IS_ERR(handle)) >> + ret = PTR_ERR(handle); >> + mutex_unlock(&sva_lock); >> + >> + return ret; >> +} >> + >> +void arm_smmu_sva_detach_dev_pasid(struct iommu_domain *domain, >> + struct device *dev, ioasid_t id) >> +{ >> + struct arm_smmu_bond *bond = NULL, *t; >> + struct mm_struct *mm = iommu_sva_domain_mm(domain); >> + struct arm_smmu_master *master = dev_iommu_priv_get(dev); >> + >> + mutex_lock(&sva_lock); >> + list_for_each_entry(t, &master->bonds, list) { >> + if (t->mm == mm) { >> + bond = t; >> + break; >> + } >> + } >> + >> + if (!WARN_ON(!bond) && refcount_dec_and_test(&bond->refs)) { >> + list_del(&bond->list); >> + arm_smmu_mmu_notifier_put(bond->smmu_mn); >> + kfree(bond); >> + } >> + mutex_unlock(&sva_lock); >> +} >> 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 afc63fce6107..bd80de0bad98 100644 >> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> @@ -1995,10 +1995,31 @@ static bool arm_smmu_capable(enum iommu_cap cap) >> } >> } >> >> +static void arm_smmu_sva_domain_free(struct iommu_domain *domain) >> +{ >> + kfree(domain); >> +} >> + >> +static const struct iommu_domain_ops arm_smmu_sva_domain_ops = { >> + .attach_dev_pasid = arm_smmu_sva_attach_dev_pasid, >> + .detach_dev_pasid = arm_smmu_sva_detach_dev_pasid, >> + .free = arm_smmu_sva_domain_free, >> +}; >> + >> static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) >> { >> struct arm_smmu_domain *smmu_domain; >> >> + if (type == IOMMU_DOMAIN_SVA) { >> + struct iommu_domain *domain; >> + >> + domain = kzalloc(sizeof(*domain), GFP_KERNEL); >> + if (domain) >> + domain->ops = &arm_smmu_sva_domain_ops; >> + >> + return domain; >> + } >> + > > I'd prefer moving all of this to arm-smmu-v3-sva.c and just call > arm_smmu_sva_domain_alloc() here Sure. > > Otherwise the patch looks fine. I'll rework the driver when I find some > time, because we can now remove arm_smmu_bond and move smmu_mn to the SVA > domain, maybe also remove sva_lock but I haven't thought it through. Yes. Intel SVA code also needs further cleanup. It's in my non-urgent task list. > > Thanks, > Jean > >> if (type != IOMMU_DOMAIN_UNMANAGED && >> type != IOMMU_DOMAIN_DMA && >> type != IOMMU_DOMAIN_DMA_FQ && >> -- >> 2.25.1 >> Best regards, baolu