[PATCH AUTOSEL 5.9 13/55] x86/boot/compressed/64: Introduce sev_status

Sasha Levin
2020-11-10T03:53:44Z

From: Joerg Roedel <jroedel@suse.de>

[ Upstream commit 3ad84246a4097010f3ae3d6944120c0be00e9e7a ]

Introduce sev_status and initialize it together with sme_me_mask to have
an indicator which SEV features are enabled.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20201028164659.27002-2-joro@8bytes.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/boot/compressed/mem_encrypt.S | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S
index dd07e7b41b115..3092ae173f94e 100644
--- a/arch/x86/boot/compressed/mem_encrypt.S
+++ b/arch/x86/boot/compressed/mem_encrypt.S
@@ -81,6 +81,19 @@ SYM_FUNC_START(set_sev_encryption_mask)

bts %rax, sme_me_mask(%rip) /* Create the encryption mask */

+ /*
+ * Read MSR_AMD64_SEV again and store it to sev_status. Can't do this in
+ * get_sev_encryption_bit() because this function is 32-bit code and
+ * shared between 64-bit and 32-bit boot path.
+ */
+ movl $MSR_AMD64_SEV, %ecx /* Read the SEV MSR */
+ rdmsr
+
+ /* Store MSR value in sev_status */
+ shlq $32, %rdx
+ orq %rdx, %rax
+ movq %rax, sev_status(%rip)
+
.Lno_sev_mask:
movq %rbp, %rsp /* Restore original stack pointer */

@@ -96,5 +109,6 @@ SYM_FUNC_END(set_sev_encryption_mask)

#ifdef CONFIG_AMD_MEM_ENCRYPT
.balign 8
-SYM_DATA(sme_me_mask, .quad 0)
+SYM_DATA(sme_me_mask, .quad 0)
+SYM_DATA(sev_status, .quad 0)
#endif
--
2.27.0