[GIT PULL 0/1] EFI fix for v4.18

[GIT PULL 0/1] EFI fix for v4.18

[Ard Biesheuvel]

The following changes since commit 9d3cce1e8b8561fed5f383d22a4d6949db4eadbe:

  Linux 4.18-rc5 (2018-07-15 12:49:31 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git efi-urgent

for you to fetch changes up to b0d2fc41203d3712585b71d8f14914ff6a266278:

  x86/efi: Access EFI MMIO data as unencrypted when SEV is active (2018-07-17 11:10:56 +0800)

----------------------------------------------------------------
Apply a fix from Brijesh to prevent the [unencrypted] SPI flash from
being mapped with the encryption bit set when running with SEV enabled.

----------------------------------------------------------------
Brijesh Singh (1):
      x86/efi: Access EFI MMIO data as unencrypted when SEV is active

 arch/x86/platform/efi/efi_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

[PATCH 1/1] x86/efi: Access EFI MMIO data as unencrypted when SEV is active

[Ard Biesheuvel]

From: Brijesh Singh <brijesh.singh@amd.com>

SEV guest fails to update the UEFI runtime variables stored in the
flash. commit 1379edd59673 ("x86/efi: Access EFI data as encrypted
when SEV is active") unconditionally maps all the UEFI runtime data
as 'encrypted' (C=1). When SEV is active the UEFI runtime data marked
as EFI_MEMORY_MAPPED_IO should be mapped as 'unencrypted' so that both
guest and hypervisor can access the data.

Fixes: 1379edd59673 ("x86/efi: Access EFI data as encrypted ...")
Cc: <stable@vger.kernel.org> # 4.15.x
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/platform/efi/efi_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 77873ce700ae..5f2eb3231607 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -417,7 +417,7 @@ static void __init __map_region(efi_memory_desc_t *md, u64 va)
 	if (!(md->attribute & EFI_MEMORY_WB))
 		flags |= _PAGE_PCD;
 
-	if (sev_active())
+	if (sev_active() && md->type != EFI_MEMORY_MAPPED_IO)
 		flags |= _PAGE_ENC;
 
 	pfn = md->phys_addr >> PAGE_SHIFT;
-- 
2.17.1

[tip:efi/urgent] x86/efi: Access EFI MMIO data as unencrypted when SEV is active

[tip-bot for Brijesh Singh]

Commit-ID:  9b788f32bee6b0b293a4bdfca4ad4bb0206407fb
Gitweb:     https://git.kernel.org/tip/9b788f32bee6b0b293a4bdfca4ad4bb0206407fb
Author:     Brijesh Singh <brijesh.singh@amd.com>
AuthorDate: Fri, 20 Jul 2018 10:28:46 +0900
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 22 Jul 2018 14:10:38 +0200

x86/efi: Access EFI MMIO data as unencrypted when SEV is active

SEV guest fails to update the UEFI runtime variables stored in the
flash.

The following commit:

  1379edd59673 ("x86/efi: Access EFI data as encrypted when SEV is active")

unconditionally maps all the UEFI runtime data as 'encrypted' (C=1).

When SEV is active the UEFI runtime data marked as EFI_MEMORY_MAPPED_IO
should be mapped as 'unencrypted' so that both guest and hypervisor can
access the data.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@vger.kernel.org> # 4.15.x
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Fixes: 1379edd59673 ("x86/efi: Access EFI data as encrypted ...")
Link: http://lkml.kernel.org/r/20180720012846.23560-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/platform/efi/efi_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 77873ce700ae..5f2eb3231607 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -417,7 +417,7 @@ static void __init __map_region(efi_memory_desc_t *md, u64 va)
 	if (!(md->attribute & EFI_MEMORY_WB))
 		flags |= _PAGE_PCD;
 
-	if (sev_active())
+	if (sev_active() && md->type != EFI_MEMORY_MAPPED_IO)
 		flags |= _PAGE_ENC;
 
 	pfn = md->phys_addr >> PAGE_SHIFT;