[RFC Part1 PATCH v3 05/17] x86, realmode: Don't decrypt trampoline area under SEV

Brijesh Singh
2017-07-24T19:07:45Z

From: Tom Lendacky <thomas.lendacky-5C7GfCeVMHo@public.gmane.org>

When SEV is active the trampoline area will need to be in encrypted
memory so only mark the area decrypted if SME is active.

Signed-off-by: Tom Lendacky <thomas.lendacky-5C7GfCeVMHo@public.gmane.org>
Signed-off-by: Brijesh Singh <brijesh.singh-5C7GfCeVMHo@public.gmane.org>
---
arch/x86/realmode/init.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 1f71980..c7eeca7 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -63,9 +63,11 @@ static void __init setup_real_mode(void)
/*
* If SME is active, the trampoline area will need to be in
* decrypted memory in order to bring up other processors
- * successfully.
+ * successfully. For SEV the trampoline area needs to be in
+ * encrypted memory, so only do this for SME.
*/
- set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT);
+ if (sme_active())
+ set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT);

memcpy(base, real_mode_blob, size);

--
2.9.4