| From | Steven Price <> | Subject | [RFC PATCH 09/14] arm64: Enforce bounce buffers for realm DMA | Date | Fri, 27 Jan 2023 11:27:53 +0000 |
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Within a realm guest it's not possible for a device emulated by the VMM to access arbitrary guest memory. So force the use of bounce buffers to ensure that the memory the emulated devices are accessing is in memory which is explicitly shared with the host.
Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> --- arch/arm64/kernel/rsi.c | 2 ++ arch/arm64/mm/init.c | 8 +++++++- 2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c index 49d36dfe0064..1a07eefdd2e9 100644 --- a/arch/arm64/kernel/rsi.c +++ b/arch/arm64/kernel/rsi.c @@ -5,6 +5,8 @@ #include <linux/jump_label.h> #include <linux/memblock.h> +#include <linux/swiotlb.h> + #include <asm/rsi.h> struct realm_config __attribute((aligned(PAGE_SIZE))) config; diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index fa9088add624..32a4710ad861 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -472,7 +472,13 @@ void __init bootmem_init(void) */ void __init mem_init(void) { - swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), SWIOTLB_VERBOSE); + if (is_realm_world()) { + swiotlb_init(true, SWIOTLB_VERBOSE | SWIOTLB_FORCE); + swiotlb_update_mem_attributes(); + } else { + swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), + SWIOTLB_VERBOSE); + } /* this will put all unused low memory onto the freelists */ memblock_free_all(); -- 2.34.1
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