drm: change func to better detect wether swiotlb is needed (913b2cb7) · Commits · 戴 / test

This commit fixes DRM failures on Xen PV systems that were introduced in v4.17 by the following commits: drm: add func to get max iomem address v2 drm/amdgpu: only enable swiotlb alloc when need v2 drm/radeon: only enable swiotlb path when need v2 The introduction of ->need_swiotlb to the ttm_dma_populate() conditionals in the radeon and amdgpu device drivers causes Gnome to immediately crash on Xen PV systems, returning the user to the login screen. The following kernel errors get logged: [ 28.554259] radeon_dp_aux_transfer_native: 200 callbacks suppressed [ 31.219821] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes) [ 31.220030] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14) [ 31.226109] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes) [ 31.226300] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14) [ 31.300734] gnome-shell[1935]: segfault at 88 ip 00007f39151cd904 sp 00007ffc97611ad8 error 4 in libmutter-cogl.so[7f3915178000+aa000] [ 31.300745] Code: 5f c3 0f 1f 40 00 48 8b 47 78 48 8b 40 40 ff e0 66 0f 1f 44 00 00 48 8b 47 78 48 8b 40 48 ff e0 66 0f 1f 44 00 00 48 8b 47 78 <48> 8b 80 88 00 00 00 ff e0 0f 1f 00 48 8b 47 78 48 8b 40 68 ff e0 [ 38.193302] radeon_dp_aux_transfer_native: 116 callbacks suppressed [ 40.009317] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes) [ 40.009488] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14) [ 40.015114] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes) [ 40.015297] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14) [ 40.028302] gnome-shell[2431]: segfault at 2dadf40 ip 0000000002dadf40 sp 00007ffcd24ea5f8 error 15 [ 40.028306] Code: 20 6e 31 00 00 00 00 00 00 00 00 37 e3 3d 2d 7f 00 00 80 f4 e6 3d 2d 7f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 c1 00 00 00 00 00 00 00 80 e1 d2 03 00 00 This commit renames drm_get_max_iomem() to drm_need_swiotlb(), adds a xen_pv_domain() check to it, and moves the bit shifting comparison that always follows its usage into the function (simplifying the drm driver code). Signed-off-by:

Michael D Labriola <michael.d.labriola@gmail.com> Reviewed-by:

Christian König <christian.koenig@amd.com> Signed-off-by:

Christian König <christian.koenig@amd.com> Link: https://patchwork.freedesktop.org/patch/286987/

drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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) {

drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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) {

drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);

drivers/gpu/drm/drm_memory.c

+16 −3

Original line number	Diff line number	Diff line
		@@ -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);

drivers/gpu/drm/radeon/radeon_device.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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 */

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