efi: arm64: Map Device with Prot Shared

Device mappings need to be emulated by the VMM so must be mapped shared
with the host.

Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20241017131434.40935-7-steven.price@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: Suzuki K Poulose

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_protected_mmio(md->phys_addr,
+					    md->num_pages << EFI_PAGE_SHIFT))
+			prot = pgprot_encrypted(prot);
+		else
+			prot = pgprot_decrypted(prot);
+		return pgprot_val(prot);
+	}
 
 	if (region_is_misaligned(md)) {
 		static bool __initdata code_is_misaligned;