diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
index 761dcfb2fec0..3e9c5034febe 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
@@ -1030,7 +1030,7 @@ static int gmc_v7_0_sw_init(void *handle)
 		pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32));
 		pr_warn("amdgpu: No coherent DMA available\n");
 	}
-	adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
+	adev->need_swiotlb = drm_need_swiotlb(dma_bits);
 
 	r = gmc_v7_0_init_microcode(adev);
 	if (r) {
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
index 34440672f938..29dde64bf2e7 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
@@ -1155,7 +1155,7 @@ static int gmc_v8_0_sw_init(void *handle)
 		pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32));
 		pr_warn("amdgpu: No coherent DMA available\n");
 	}
-	adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
+	adev->need_swiotlb = drm_need_swiotlb(dma_bits);
 
 	r = gmc_v8_0_init_microcode(adev);
 	if (r) {
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index 600259b4e291..840f3bd0fcbe 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -1011,7 +1011,7 @@ static int gmc_v9_0_sw_init(void *handle)
 		pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32));
 		printk(KERN_WARNING "amdgpu: No coherent DMA available.\n");
 	}
-	adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
+	adev->need_swiotlb = drm_need_swiotlb(dma_bits);
 
 	if (adev->gmc.xgmi.supported) {
 		r = gfxhub_v1_1_get_xgmi_info(adev);
diff --git a/drivers/gpu/drm/drm_memory.c b/drivers/gpu/drm/drm_memory.c
index 40c4349cb939..8dbcdc77f6bf 100644
--- a/drivers/gpu/drm/drm_memory.c
+++ b/drivers/gpu/drm/drm_memory.c
@@ -35,6 +35,7 @@
 
 #include <linux/highmem.h>
 #include <linux/export.h>
+#include <xen/xen.h>
 #include <drm/drmP.h>
 #include "drm_legacy.h"
 
@@ -150,15 +151,27 @@ void drm_legacy_ioremapfree(struct drm_local_map *map, struct drm_device *dev)
 }
 EXPORT_SYMBOL(drm_legacy_ioremapfree);
 
-u64 drm_get_max_iomem(void)
+bool drm_need_swiotlb(int dma_bits)
 {
 	struct resource *tmp;
 	resource_size_t max_iomem = 0;
 
+	/*
+	 * Xen paravirtual hosts require swiotlb regardless of requested dma
+	 * transfer size.
+	 *
+	 * NOTE: Really, what it requires is use of the dma_alloc_coherent
+	 *       allocator used in ttm_dma_populate() instead of
+	 *       ttm_populate_and_map_pages(), which bounce buffers so much in
+	 *       Xen it leads to swiotlb buffer exhaustion.
+	 */
+	if (xen_pv_domain())
+		return true;
+
 	for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling) {
 		max_iomem = max(max_iomem,  tmp->end);
 	}
 
-	return max_iomem;
+	return max_iomem > ((u64)1 << dma_bits);
 }
-EXPORT_SYMBOL(drm_get_max_iomem);
+EXPORT_SYMBOL(drm_need_swiotlb);
diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 53f29a115104..0a9312ea250a 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1388,7 +1388,7 @@ int radeon_device_init(struct radeon_device *rdev,
 		pci_set_consistent_dma_mask(rdev->pdev, DMA_BIT_MASK(32));
 		pr_warn("radeon: No coherent DMA available\n");
 	}
-	rdev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
+	rdev->need_swiotlb = drm_need_swiotlb(dma_bits);
 
 	/* Registers mapping */
 	/* TODO: block userspace mapping of io register */
diff --git a/include/drm/drm_cache.h b/include/drm/drm_cache.h
index 97fc498dc767..987ff16b9420 100644
--- a/include/drm/drm_cache.h
+++ b/include/drm/drm_cache.h
@@ -38,7 +38,7 @@
 void drm_clflush_pages(struct page *pages[], unsigned long num_pages);
 void drm_clflush_sg(struct sg_table *st);
 void drm_clflush_virt_range(void *addr, unsigned long length);
-u64 drm_get_max_iomem(void);
+bool drm_need_swiotlb(int dma_bits);
 
 
 static inline bool drm_arch_can_wc_memory(void)