From: Tom Lendacky <thomas.lendacky@amd.com>
Date: Fri, 20 Oct 2017 09:30:49 -0500
Subject: x86/efi: Access EFI data as encrypted when SEV is active
Git-commit: 1379edd5967346a1fa79b8dc3e9ca261576c6bc9
Patch-mainline: v4.15-rc1
References: bsc#1063068

EFI data is encrypted when the kernel is run under SEV. Update the
page table references to be sure the EFI memory areas are accessed
encrypted.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: linux-efi@vger.kernel.org
Cc: kvm@vger.kernel.org
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20171020143059.3291-8-brijesh.singh@amd.com

Acked-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/platform/efi/efi_64.c |   16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -32,6 +32,7 @@
 #include <linux/reboot.h>
 #include <linux/slab.h>
 #include <linux/ucs2_string.h>
+#include <linux/mem_encrypt.h>
 
 #include <asm/setup.h>
 #include <asm/page.h>
@@ -369,7 +370,11 @@ int __init efi_setup_page_tables(unsigne
 	 * as trim_bios_range() will reserve the first page and isolate it away
 	 * from memory allocators anyway.
 	 */
-	if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, _PAGE_RW)) {
+	pf = _PAGE_RW;
+	if (sev_active())
+		pf |= _PAGE_ENC;
+
+	if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, pf)) {
 		pr_err("Failed to create 1:1 mapping for the first page!\n");
 		return 1;
 	}
@@ -412,6 +417,9 @@ static void __init __map_region(efi_memo
 	if (!(md->attribute & EFI_MEMORY_WB))
 		flags |= _PAGE_PCD;
 
+	if (sev_active())
+		flags |= _PAGE_ENC;
+
 	pfn = md->phys_addr >> PAGE_SHIFT;
 	if (kernel_map_pages_in_pgd(pgd, pfn, va, md->num_pages, flags))
 		pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
@@ -538,6 +546,9 @@ static int __init efi_update_mem_attr(st
 	if (!(md->attribute & EFI_MEMORY_RO))
 		pf |= _PAGE_RW;
 
+	if (sev_active())
+		pf |= _PAGE_ENC;
+
 	return efi_update_mappings(md, pf);
 }
 
@@ -589,6 +600,9 @@ void __init efi_runtime_update_mappings(
 			(md->type != EFI_RUNTIME_SERVICES_CODE))
 			pf |= _PAGE_RW;
 
+		if (sev_active())
+			pf |= _PAGE_ENC;
+
 		efi_update_mappings(md, pf);
 	}
 }