From: Tom Lendacky <thomas.lenda...@amd.com>

When Secure Encrypted Virtualization is active instruction fetches are
always interpreted as being from encrypted memory so the trampoline area
must remain encrypted when SEV is active.

Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
---
 arch/x86/realmode/init.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index c3edb49..f3207e5 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -138,10 +138,13 @@ static void __init set_real_mode_permissions(void)
        /*
         * If memory encryption is active, the trampoline area will need to
         * be in non-encrypted memory in order to bring up other processors
-        * successfully.
+        * successfully. This only applies to SME, SEV requires the trampoline
+        * to be encrypted.
         */
-       sme_early_mem_dec(__pa(base), size);
-       sme_set_mem_dec(base, size);
+       if (!sev_active) {
+               sme_early_mem_dec(__pa(base), size);
+               sme_set_mem_dec(base, size);
+       }
 
        set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
        set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);

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