x86/realmode: Don't decrypt trampoline area under SEV

tlendacky · KAGA-KOKO · commit fcdcd6cdd98f · 2017-11-07T15:35:55.000+01:00
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@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: Laura Abbott <labbott@redhat.com> Cc: kvm@vger.kernel.org Cc: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Link: https://lkml.kernel.org/r/20171020143059.3291-5-brijesh.singh@amd.com
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
@@ -64,9 +64,10 @@ 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. This is not needed for SEV.
 	 */
-	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);
 
