1 files changed, 10 insertions, 13 deletions

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index af765c813cc8..efaf5eab40a1 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -52,15 +52,17 @@ struct iommu_dma_cookie {
 };
 
 static DEFINE_STATIC_KEY_FALSE(iommu_deferred_attach_enabled);
+bool iommu_dma_forcedac __read_mostly;
 
-void iommu_dma_free_cpu_cached_iovas(unsigned int cpu,
-		struct iommu_domain *domain)
+static int __init iommu_dma_forcedac_setup(char *str)
 {
-	struct iommu_dma_cookie *cookie = domain->iova_cookie;
-	struct iova_domain *iovad = &cookie->iovad;
+	int ret = kstrtobool(str, &iommu_dma_forcedac);
 
-	free_cpu_cached_iovas(cpu, iovad);
+	if (!ret && iommu_dma_forcedac)
+		pr_info("Forcing DAC for PCI devices\n");
+	return ret;
 }
+early_param("iommu.forcedac", iommu_dma_forcedac_setup);
 
 static void iommu_dma_entry_dtor(unsigned long data)
 {
@@ -304,10 +306,7 @@ static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad)
 
 	cookie = container_of(iovad, struct iommu_dma_cookie, iovad);
 	domain = cookie->fq_domain;
-	/*
-	 * The IOMMU driver supporting DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE
-	 * implies that ops->flush_iotlb_all must be non-NULL.
-	 */
+
 	domain->ops->flush_iotlb_all(domain);
 }
 
@@ -334,7 +333,6 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	unsigned long order, base_pfn;
 	struct iova_domain *iovad;
-	int attr;
 
 	if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)
 		return -EINVAL;
@@ -371,8 +369,7 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 	init_iova_domain(iovad, 1UL << order, base_pfn);
 
 	if (!cookie->fq_domain && (!dev || !dev_is_untrusted(dev)) &&
-	    !iommu_domain_get_attr(domain, DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) &&
-	    attr) {
+	    domain->ops->flush_iotlb_all && !iommu_get_dma_strict(domain)) {
 		if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
 					  iommu_dma_entry_dtor))
 			pr_warn("iova flush queue initialization failed\n");
@@ -444,7 +441,7 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
 		dma_limit = min(dma_limit, (u64)domain->geometry.aperture_end);
 
 	/* Try to get PCI devices a SAC address */
-	if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev))
+	if (dma_limit > DMA_BIT_MASK(32) && !iommu_dma_forcedac && dev_is_pci(dev))
 		iova = alloc_iova_fast(iovad, iova_len,
 				       DMA_BIT_MASK(32) >> shift, false);