diff mbox

[v7,23/36] x86, realmode: Decrypt trampoline area if memory encryption is active

Message ID 20170616185412.18967.91559.stgit@tlendack-t1.amdoffice.net (mailing list archive)
State New, archived
Headers show

Commit Message

Tom Lendacky June 16, 2017, 6:54 p.m. UTC 
When Secure Memory Encryption is enabled, the trampoline area must not
be encrypted. A CPU running in real mode will not be able to decrypt
memory that has been encrypted because it will not be able to use addresses
with the memory encryption mask.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/realmode/init.c |    8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Borislav Petkov June 21, 2017, 9:43 a.m. UTC | #1 
On Fri, Jun 16, 2017 at 01:54:12PM -0500, Tom Lendacky wrote:
> When Secure Memory Encryption is enabled, the trampoline area must not
> be encrypted. A CPU running in real mode will not be able to decrypt
> memory that has been encrypted because it will not be able to use addresses
> with the memory encryption mask.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/x86/realmode/init.c |    8 ++++++++
>  1 file changed, 8 insertions(+)

Subject: x86/realmode: ...

other than that:

Reviewed-by: Borislav Petkov <bp@suse.de>
diff mbox

Patch

diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index cd4be19..d6ddc7e 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -1,6 +1,7 @@ 
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/memblock.h>
+#include <linux/mem_encrypt.h>
 
 #include <asm/set_memory.h>
 #include <asm/pgtable.h>
@@ -59,6 +60,13 @@  static void __init setup_real_mode(void)
 
 	base = (unsigned char *)real_mode_header;
 
+	/*
+	 * If SME is active, the trampoline area will need to be in
+	 * decrypted memory in order to bring up other processors
+	 * successfully.
+	 */
+	set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT);
+
 	memcpy(base, real_mode_blob, size);
 
 	phys_base = __pa(base);