Re: [PATCH v5 12/19] efi: arm64: Map Device with Prot Shared
From: Gavin Shan <hidden>
Date: 2024-09-10 04:15:53
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On 8/19/24 11:19 PM, Steven Price wrote:
quoted hunk ↗ jump to hunk
From: Suzuki K Poulose <suzuki.poulose@arm.com> Device mappings need to be emualted by the VMM so must be mapped shared with the host. Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> --- Changes since v4: * Reworked to use arm64_is_iomem_private() to decide whether the memory needs to be decrypted or not. --- arch/arm64/kernel/efi.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c index 712718aed5dd..95f8e8bf07f8 100644 --- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c@@ -34,8 +34,16 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md) u64 attr = md->attribute; u32 type = md->type; - if (type == EFI_MEMORY_MAPPED_IO) - return PROT_DEVICE_nGnRE; + if (type == EFI_MEMORY_MAPPED_IO) { + pgprot_t prot = __pgprot(PROT_DEVICE_nGnRE); + + if (arm64_is_iomem_private(md->phys_addr, + md->num_pages << EFI_PAGE_SHIFT)) + prot = pgprot_encrypted(prot); + else + prot = pgprot_decrypted(prot); + return pgprot_val(prot); + }
Question: the second parameter (@size) passed to arm64_is_iomem_private() covers the whole region. In [PATCH v5 10/19] arm64: Override set_fixmap_io, the size has been truncated to the granule size (4KB). They look inconsistent and I don't understand the reason. Thanks, Gavin