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.
Signed-off-by: Jason Gunthorpe jgg@nvidia.com --- drivers/iommu/amd/iommu.c | 2 ++ drivers/iommu/intel/iommu.c | 4 ++++ include/linux/iommu.h | 5 +++++ 3 files changed, 11 insertions(+)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index d3b39d0416fa32..d0802cab2a2f0c 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -2286,6 +2286,8 @@ 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 48cdcd0a5cf346..438ba997fa230e 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4458,7 +4458,11 @@ static bool intel_iommu_capable(struct device *dev, enum iommu_cap cap) return irq_remapping_enabled == 1; if (cap == IOMMU_CAP_PRE_BOOT_PROTECTION) return dmar_platform_optin(); + if (cap == IOMMU_CAP_ENFORCE_CACHE_COHERENCY) { + struct device_domain_info *info = dev_iommu_priv_get(dev);
+ return ecap_sc_support(info->iommu->ecap); + } return false; }
diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 3c9da1f8979e3a..40cf2d8393465f 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -108,6 +108,11 @@ 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 */