Messages in this thread | | | Date | Mon, 21 Mar 2022 18:37:06 +0800 | From | Lu Baolu <> | Subject | Re: [PATCH RFC 04/11] iommu/vt-d: Add SVA domain support |
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On 2022/3/21 15:45, Tian, Kevin wrote: >> From: Lu Baolu <baolu.lu@linux.intel.com> >> Sent: Sunday, March 20, 2022 2:40 PM >> >> Add support for SVA domain allocation and provide an SVA-specific >> iommu_domain_ops. >> >> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> >> --- >> include/linux/intel-iommu.h | 1 + >> drivers/iommu/intel/iommu.c | 12 ++++++++++++ >> drivers/iommu/intel/svm.c | 34 ++++++++++++++++++++++++++++++++++ >> 3 files changed, 47 insertions(+) >> >> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h >> index 2f9891cb3d00..c14283137fb5 100644 >> --- a/include/linux/intel-iommu.h >> +++ b/include/linux/intel-iommu.h >> @@ -744,6 +744,7 @@ void intel_svm_unbind(struct iommu_sva *handle); >> u32 intel_svm_get_pasid(struct iommu_sva *handle); >> int intel_svm_page_response(struct device *dev, struct iommu_fault_event >> *evt, >> struct iommu_page_response *msg); >> +extern const struct iommu_domain_ops intel_svm_domain_ops; >> >> struct intel_svm_dev { >> struct list_head list; >> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c >> index c1b91bce1530..d55dca3eacf8 100644 >> --- a/drivers/iommu/intel/iommu.c >> +++ b/drivers/iommu/intel/iommu.c >> @@ -4318,6 +4318,18 @@ static struct iommu_domain >> *intel_iommu_domain_alloc(unsigned type) >> return domain; >> case IOMMU_DOMAIN_IDENTITY: >> return &si_domain->domain; >> +#ifdef CONFIG_INTEL_IOMMU_SVM >> + case IOMMU_DOMAIN_SVA: >> + dmar_domain = alloc_domain(type); >> + if (!dmar_domain) { >> + pr_err("Can't allocate sva domain\n"); >> + return NULL; >> + } >> + domain = &dmar_domain->domain; >> + domain->ops = &intel_svm_domain_ops; >> + >> + return domain; >> +#endif /* CONFIG_INTEL_IOMMU_SVM */ >> default: >> return NULL; >> } >> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c >> index ee5ecde5b318..b9f4dd7057d1 100644 >> --- a/drivers/iommu/intel/svm.c >> +++ b/drivers/iommu/intel/svm.c >> @@ -932,3 +932,37 @@ int intel_svm_page_response(struct device *dev, >> mutex_unlock(&pasid_mutex); >> return ret; >> } >> + >> +static int intel_svm_attach_dev_pasid(struct iommu_domain *domain, >> + struct device *dev, ioasid_t pasid) >> +{ >> + struct device_domain_info *info = dev_iommu_priv_get(dev); >> + struct mm_struct *mm = domain->sva_cookie; >> + struct intel_iommu *iommu = info->iommu; >> + struct iommu_sva *sva; >> + >> + mutex_lock(&pasid_mutex); >> + sva = intel_svm_bind_mm(iommu, dev, mm); >> + mutex_unlock(&pasid_mutex); >> + > > I'm not sure whether this is the right implementation of this callback. > In last patch you said it will be used for multiple usages but here it > is fixed to mm binding.
It is for svm domain ops so it should be mm binding only. For other usages, they should have different domain ops.
> Also the pasid argument is not used at all > and instead it is retrieved from mm struct implicitly.
The pasid is not used here because it has already been stored in mm->pasid. Since it's only for SVM domain, I think it's okay.
> > Basically SVA requires three steps: > > 1) alloc a SVA-type domain; > 2) construct the domain to wrap mm; > 3) attach the domain to a PASID; > > If we aim .attach_dev_pasid to be generic it may suggest that 1) and 2) > should be done before .attach_dev_pasid then within this callback it > just deals with domain/pasid attach in a generic way.
You are right. This code does have room for further cleanup. I would like to put that in a separated series so that we could focus on the generic SVA and IOPF refactoring.
> >> + return IS_ERR_OR_NULL(sva); >> +} >> + >> +static void intel_svm_detach_dev_pasid(struct iommu_domain *domain, >> + struct device *dev, ioasid_t pasid) >> +{ >> + mutex_lock(&pasid_mutex); >> + intel_svm_unbind_mm(dev, pasid); >> + mutex_unlock(&pasid_mutex); >> +} >> + >> +static void intel_svm_domain_free(struct iommu_domain *domain) >> +{ >> + kfree(domain); >> +} >> + >> +const struct iommu_domain_ops intel_svm_domain_ops = { >> + .attach_dev_pasid = intel_svm_attach_dev_pasid, >> + .detach_dev_pasid = intel_svm_detach_dev_pasid, >> + .free = intel_svm_domain_free, >> +}; >> -- >> 2.25.1 >
Best regards, baolu
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