Re: [PATCH v6 7/8] iommu/vt-d: Add nested domain allocation

On 10/20/23 5:32 PM, Yi Liu wrote:

From: Lu Baolu baolu.lu@linux.intel.com

This adds the support for IOMMU_HWPT_DATA_VTD_S1 type.

Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Yi Liu yi.l.liu@intel.com

---

drivers/iommu/intel/iommu.c | 39 ++++++++++++++++++++++++++----------- 1 file changed, 28 insertions(+), 11 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index b47025fbdea4..c7704e7efd4a 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4076,7 +4076,7 @@ intel_iommu_domain_alloc_user(struct device *dev, u32 flags, struct iommu_domain *parent, const struct iommu_user_data *user_data) {

• struct iommu_domain *domain;

• bool request_nest_parent = flags & IOMMU_HWPT_ALLOC_NEST_PARENT; struct intel_iommu *iommu;

if (flags & (~IOMMU_HWPT_ALLOC_NEST_PARENT)) @@ -4086,18 +4086,35 @@ intel_iommu_domain_alloc_user(struct device *dev, u32 flags, if (!iommu) return ERR_PTR(-ENODEV);

• if ((flags & IOMMU_HWPT_ALLOC_NEST_PARENT) && !ecap_nest(iommu->ecap))

• if (!user_data) { /* Must be PAGING domain */

• struct iommu_domain *domain;
  

• if (request_nest_parent && !ecap_nest(iommu->ecap))
  

Hardware capability is not sufficient. How about adding below helper:

diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h index b5f33a7c1973..b04bbabcd696 100644 --- a/drivers/iommu/intel/iommu.h +++ b/drivers/iommu/intel/iommu.h @@ -540,6 +540,8 @@ enum { #define sm_supported(iommu) (intel_iommu_sm && ecap_smts((iommu)->ecap)) #define pasid_supported(iommu) (sm_supported(iommu) && \ ecap_pasid((iommu)->ecap)) +#define nested_supported(iommu) (sm_supported(iommu) && \ + ecap_nest((iommu)->ecap))

struct pasid_entry; struct pasid_state_entry;

And, use nested_supported() here and bleow

• 	return ERR_PTR(-EOPNOTSUPP);
  

• if (parent)
  

• 	return ERR_PTR(-EINVAL);
  

• /*
  

•  * domain_alloc_user op needs to fully initialize a domain
  

•  * before return, so uses iommu_domain_alloc() here for
  

•  * simple.
  

•  */
  

• domain = iommu_domain_alloc(dev->bus);
  

• if (!domain)
  

• 	return ERR_PTR(-ENOMEM);
  

• return domain;
  

• }
• /* Must be nested domain */
• if (!ecap_nest(iommu->ecap))

...here.

• return ERR_PTR(-EOPNOTSUPP);
  

• if (user_data->type != IOMMU_HWPT_DATA_VTD_S1) return ERR_PTR(-EOPNOTSUPP);
• if (!parent || parent->ops != intel_iommu_ops.default_domain_ops)

• return ERR_PTR(-EINVAL);
  

• if (request_nest_parent)

• return ERR_PTR(-EINVAL);
  

• /*

• * domain_alloc_user op needs to fully initialize a domain
  

• * before return, so uses iommu_domain_alloc() here for
  

• * simple.
  

• */
  

• domain = iommu_domain_alloc(dev->bus);
• if (!domain)

• domain = ERR_PTR(-ENOMEM);
  

• return domain;

• return intel_nested_domain_alloc(parent, user_data); }

static void intel_iommu_domain_free(struct iommu_domain *domain)

Best regards, baolu