Commit 1ff2fc02862d for kernel

commit 1ff2fc02862d52e18fd3daabcfe840ec27e920a8
Author: Tom Lendacky <thomas.lendacky@amd.com>
Date:   Wed Oct 20 13:02:11 2021 -0500

    x86/sme: Explicitly map new EFI memmap table as encrypted

    Reserving memory using efi_mem_reserve() calls into the x86
    efi_arch_mem_reserve() function. This function will insert a new EFI
    memory descriptor into the EFI memory map representing the area of
    memory to be reserved and marking it as EFI runtime memory. As part
    of adding this new entry, a new EFI memory map is allocated and mapped.
    The mapping is where a problem can occur. This new memory map is mapped
    using early_memremap() and generally mapped encrypted, unless the new
    memory for the mapping happens to come from an area of memory that is
    marked as EFI_BOOT_SERVICES_DATA memory. In this case, the new memory will
    be mapped unencrypted. However, during replacement of the old memory map,
    efi_mem_type() is disabled, so the new memory map will now be long-term
    mapped encrypted (in efi.memmap), resulting in the map containing invalid
    data and causing the kernel boot to crash.

    Since it is known that the area will be mapped encrypted going forward,
    explicitly map the new memory map as encrypted using early_memremap_prot().

    Cc: <stable@vger.kernel.org> # 4.14.x
    Fixes: 8f716c9b5feb ("x86/mm: Add support to access boot related data in the clear")
    Link: https://lore.kernel.org/all/ebf1eb2940405438a09d51d121ec0d02c8755558.1634752931.git.thomas.lendacky@amd.com/
    Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
    [ardb: incorporate Kconfig fix by Arnd]
    Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 95dd1ee01546..9636a3122496 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1932,6 +1932,7 @@ config EFI
 	depends on ACPI
 	select UCS2_STRING
 	select EFI_RUNTIME_WRAPPERS
+	select ARCH_USE_MEMREMAP_PROT
 	help
 	  This enables the kernel to use EFI runtime services that are
 	  available (such as the EFI variable services).
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index b15ebfe40a73..b0b848d6933a 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -277,7 +277,8 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
 		return;
 	}

-	new = early_memremap(data.phys_map, data.size);
+	new = early_memremap_prot(data.phys_map, data.size,
+				  pgprot_val(pgprot_encrypted(FIXMAP_PAGE_NORMAL)));
 	if (!new) {
 		pr_err("Failed to map new boot services memmap\n");
 		return;