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author | Thomas Zimmermann <tzimmermann@suse.de> | 2021-01-12 09:10:31 +0100 |
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committer | Thomas Zimmermann <tzimmermann@suse.de> | 2021-01-13 14:22:29 +0100 |
commit | 3abc66706385e08f7003ca746be005e4c2152b09 (patch) | |
tree | ff9073a9424c95d96b2088f44f00a9feb044358e /drivers/gpu/drm/drm_cache.c | |
parent | ff28a9f8d3b4e2e6d07e37e0f5e15119ee4aff55 (diff) | |
download | linux-stable-3abc66706385e08f7003ca746be005e4c2152b09.tar.gz linux-stable-3abc66706385e08f7003ca746be005e4c2152b09.tar.bz2 linux-stable-3abc66706385e08f7003ca746be005e4c2152b09.zip |
drm: Implement drm_need_swiotlb() in drm_cache.c
The function is declared in drm_cache.h. I also removed the curly
braces from the for loop to adhere to kernel coding style.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210112081035.6882-3-tzimmermann@suse.de
Diffstat (limited to 'drivers/gpu/drm/drm_cache.c')
-rw-r--r-- | drivers/gpu/drm/drm_cache.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c index 0fe3c496002a..49551a7fa22f 100644 --- a/drivers/gpu/drm/drm_cache.c +++ b/drivers/gpu/drm/drm_cache.c @@ -30,6 +30,7 @@ #include <linux/export.h> #include <linux/highmem.h> +#include <xen/xen.h> #include <drm/drm_cache.h> @@ -176,3 +177,34 @@ drm_clflush_virt_range(void *addr, unsigned long length) #endif } EXPORT_SYMBOL(drm_clflush_virt_range); + +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; + + /* + * Enforce dma_alloc_coherent when memory encryption is active as well + * for the same reasons as for Xen paravirtual hosts. + */ + if (mem_encrypt_active()) + return true; + + for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling) + max_iomem = max(max_iomem, tmp->end); + + return max_iomem > ((u64)1 << dma_bits); +} +EXPORT_SYMBOL(drm_need_swiotlb); |