Re: [PATCH v5 01/19] iommu: Add IOMMU_CAP_ENFORCE_CACHE_COHERENCY

On 2022/11/17 05:00, Jason Gunthorpe wrote:

This queries if a domain linked to a device should expect to support enforce_cache_coherency() so iommufd can negotiate the rules for when a domain should be shared or not.

For iommufd a device that declares IOMMU_CAP_ENFORCE_CACHE_COHERENCY will not be attached to a domain that does not support it.

Reviewed-by: Lu Baolu baolu.lu@linux.intel.com Reviewed-by: Kevin Tian kevin.tian@intel.com Tested-by: Nicolin Chen nicolinc@nvidia.com Tested-by: Yi Liu yi.l.liu@intel.com Tested-by: Lixiao Yang lixiao.yang@intel.com Tested-by: Matthew Rosato mjrosato@linux.ibm.com

looks like Yu He's test-by was missed. :-) She has given it in below link.

https://lore.kernel.org/kvm/DM6PR11MB268429C4986C7808760CCE72E0049@DM6PR11MB...

Signed-off-by: Jason Gunthorpe jgg@nvidia.com

drivers/iommu/amd/iommu.c | 2 ++ drivers/iommu/intel/iommu.c | 16 +++++++++++----- include/linux/iommu.h | 5 +++++ 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 45299eb7e8e306..240c535e317cc7 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -2278,6 +2278,8 @@ static bool amd_iommu_capable(struct device *dev, enum iommu_cap cap) return false; case IOMMU_CAP_PRE_BOOT_PROTECTION: return amdr_ivrs_remap_support;

• case IOMMU_CAP_ENFORCE_CACHE_COHERENCY:

• return true;
  

  default: break; }

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index f298e51d5aa67a..157c9727411076 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4450,14 +4450,20 @@ static bool intel_iommu_enforce_cache_coherency(struct iommu_domain *domain) static bool intel_iommu_capable(struct device *dev, enum iommu_cap cap) {

• if (cap == IOMMU_CAP_CACHE_COHERENCY)

• struct device_domain_info *info = dev_iommu_priv_get(dev);
• switch (cap) {
• case IOMMU_CAP_CACHE_COHERENCY: return true;

• if (cap == IOMMU_CAP_INTR_REMAP)

• case IOMMU_CAP_INTR_REMAP: return irq_remapping_enabled == 1;

• if (cap == IOMMU_CAP_PRE_BOOT_PROTECTION)

• case IOMMU_CAP_PRE_BOOT_PROTECTION: return dmar_platform_optin();

• return false;

• case IOMMU_CAP_ENFORCE_CACHE_COHERENCY:

• return ecap_sc_support(info->iommu->ecap);
  

• default:

• return false;
  

• } }

static struct iommu_device *intel_iommu_probe_device(struct device *dev) diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 68d7d304cdb761..a09fd32d8cc273 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -124,6 +124,11 @@ enum iommu_cap { IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ IOMMU_CAP_PRE_BOOT_PROTECTION, /* Firmware says it used the IOMMU for DMA protection and we should too */

• /*

• * Per-device flag indicating if enforce_cache_coherency() will work on
  

• * this device.
  

• */
  

• IOMMU_CAP_ENFORCE_CACHE_COHERENCY, };

/* These are the possible reserved region types */