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 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 */