[PATCH V3 09/13] DMA: Add dma_map_decrypted/dma_unmap_encrypted() function
From: Tianyu Lan <hidden>
Date: 2021-08-09 17:57:16
Also in:
linux-arch, linux-hyperv, linux-iommu, linux-scsi, lkml, xen-devel
Subsystem:
dma mapping helpers, the rest · Maintainers:
Marek Szyprowski, Linus Torvalds
From: Tianyu Lan <redacted> In Hyper-V Isolation VM with AMD SEV, swiotlb boucne buffer needs to be mapped into address space above vTOM and so introduce dma_map_decrypted/dma_unmap_encrypted() to map/unmap bounce buffer memory. The platform can populate man/unmap callback in the dma memory decrypted ops. --- include/linux/dma-map-ops.h | 9 +++++++++ kernel/dma/mapping.c | 22 ++++++++++++++++++++++ 2 files changed, 31 insertions(+)
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 0d53a96a3d64..01d60a024e45 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h@@ -71,6 +71,11 @@ struct dma_map_ops { unsigned long (*get_merge_boundary)(struct device *dev); }; +struct dma_memory_decrypted_ops { + void *(*map)(void *addr, unsigned long size); + void (*unmap)(void *addr); +}; + #ifdef CONFIG_DMA_OPS #include <asm/dma-mapping.h>
@@ -374,6 +379,10 @@ static inline void debug_dma_dump_mappings(struct device *dev) } #endif /* CONFIG_DMA_API_DEBUG */ +void *dma_map_decrypted(void *addr, unsigned long size); +int dma_unmap_decrypted(void *addr, unsigned long size); + extern const struct dma_map_ops dma_dummy_ops; +extern struct dma_memory_decrypted_ops dma_memory_generic_decrypted_ops; #endif /* _LINUX_DMA_MAP_OPS_H */
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 2b06a809d0b9..6fb150dc1750 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c@@ -13,11 +13,13 @@ #include <linux/of_device.h> #include <linux/slab.h> #include <linux/vmalloc.h> +#include <asm/set_memory.h> #include "debug.h" #include "direct.h" bool dma_default_coherent; +struct dma_memory_decrypted_ops dma_memory_generic_decrypted_ops; /* * Managed DMA API */
@@ -736,3 +738,23 @@ unsigned long dma_get_merge_boundary(struct device *dev) return ops->get_merge_boundary(dev); } EXPORT_SYMBOL_GPL(dma_get_merge_boundary); + +void *dma_map_decrypted(void *addr, unsigned long size) +{ + if (set_memory_decrypted((unsigned long)addr, + size / PAGE_SIZE)) + return NULL; + + if (dma_memory_generic_decrypted_ops.map) + return dma_memory_generic_decrypted_ops.map(addr, size); + else + return addr; +} + +int dma_unmap_encrypted(void *addr, unsigned long size) +{ + if (dma_memory_generic_decrypted_ops.unmap) + dma_memory_generic_decrypted_ops.unmap(addr); + + return set_memory_encrypted((unsigned long)addr, size / PAGE_SIZE); +}
--
2.25.1