From: Jason Gunthorpe <jgg@nvidia.com>
Date: Thu, 26 Mar 2026 19:30:32 +0000 (-0300)
Subject: iommu/dma: Always allow DMA-FQ when iommupt provides the iommu_domain
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1c18a1212c772b6a19e8583f2fca73f3a47b60fd;p=thirdparty%2Fkernel%2Flinux.git

iommu/dma: Always allow DMA-FQ when iommupt provides the iommu_domain

iommupt always supports the semantics required for DMA-FQ, when drivers
are converted to use it they automatically get support.

Detect iommpt directly instead of using IOMMU_CAP_DEFERRED_FLUSH and
remove IOMMU_CAP_DEFERRED_FLUSH from converted drivers.

This will also enable DMA-FQ on RISC-V.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index f1814fee51823..2e553e2051aa0 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2978,8 +2978,6 @@ static bool amd_iommu_capable(struct device *dev, enum iommu_cap cap)
 		return amdr_ivrs_remap_support;
 	case IOMMU_CAP_ENFORCE_CACHE_COHERENCY:
 		return true;
-	case IOMMU_CAP_DEFERRED_FLUSH:
-		return true;
 	case IOMMU_CAP_DIRTY_TRACKING: {
 		struct amd_iommu *iommu = get_amd_iommu_from_dev(dev);
 
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 5dac64be61bb2..fbed93f8bf0ad 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -14,6 +14,7 @@
 #include <linux/device.h>
 #include <linux/dma-direct.h>
 #include <linux/dma-map-ops.h>
+#include <linux/generic_pt/iommu.h>
 #include <linux/gfp.h>
 #include <linux/huge_mm.h>
 #include <linux/iommu.h>
@@ -648,6 +649,15 @@ static void iommu_dma_init_options(struct iommu_dma_options *options,
 	}
 }
 
+static bool iommu_domain_supports_fq(struct device *dev,
+				     struct iommu_domain *domain)
+{
+	/* iommupt always supports DMA-FQ */
+	if (iommupt_from_domain(domain))
+		return true;
+	return device_iommu_capable(dev, IOMMU_CAP_DEFERRED_FLUSH);
+}
+
 /**
  * iommu_dma_init_domain - Initialise a DMA mapping domain
  * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
@@ -706,7 +716,8 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, struct device *dev
 
 	/* If the FQ fails we can simply fall back to strict mode */
 	if (domain->type == IOMMU_DOMAIN_DMA_FQ &&
-	    (!device_iommu_capable(dev, IOMMU_CAP_DEFERRED_FLUSH) || iommu_dma_init_fq(domain)))
+	    (!iommu_domain_supports_fq(dev, domain) ||
+	     iommu_dma_init_fq(domain)))
 		domain->type = IOMMU_DOMAIN_DMA;
 
 	return iova_reserve_iommu_regions(dev, domain);
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5dca8e525c73c..80b183e207e59 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -3212,8 +3212,6 @@ static bool intel_iommu_capable(struct device *dev, enum iommu_cap cap)
 
 	switch (cap) {
 	case IOMMU_CAP_CACHE_COHERENCY:
-	case IOMMU_CAP_DEFERRED_FLUSH:
-		return true;
 	case IOMMU_CAP_PRE_BOOT_PROTECTION:
 		return dmar_platform_optin();
 	case IOMMU_CAP_ENFORCE_CACHE_COHERENCY: