diff mbox series

x86/sev: Fix SEV check in sev_map_percpu_data()

Message ID 20240102133747.27053-1-kirill.shutemov@linux.intel.com
State New
Headers
Series x86/sev: Fix SEV check in sev_map_percpu_data() |

Commit Message

Kirill A. Shutemov Jan. 2, 2024, 1:37 p.m. UTC 
  The function sev_map_percpu_data() checks if it is running on an SEV
platform by checking the CC_ATTR_GUEST_MEM_ENCRYPT attribute. However,
this attribute is also defined for TDX.

To avoid false positives, add a cc_vendor check.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/kernel/kvm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Borislav Petkov Jan. 2, 2024, 2:31 p.m. UTC | #1 
On Tue, Jan 02, 2024 at 04:37:47PM +0300, Kirill A. Shutemov wrote:
> The function sev_map_percpu_data() checks if it is running on an SEV
> platform by checking the CC_ATTR_GUEST_MEM_ENCRYPT attribute. However,
> this attribute is also defined for TDX.
> 
> To avoid false positives, add a cc_vendor check.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Fixes: 4d96f9109109 ("x86/sev: Replace occurrences of sev_active() with cc_platform_has()")
Suggested-by: Borislav Petkov (AMD) <bp@alien8.de>

Thx.
David Rientjes Jan. 2, 2024, 6:27 p.m. UTC | #2 
On Tue, 2 Jan 2024, Kirill A. Shutemov wrote:

> The function sev_map_percpu_data() checks if it is running on an SEV
> platform by checking the CC_ATTR_GUEST_MEM_ENCRYPT attribute. However,
> this attribute is also defined for TDX.
> 
> To avoid false positives, add a cc_vendor check.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Acked-by: David Rientjes <rientjes@google.com>
diff mbox series

Patch

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 0ddb3bd0f1aa..5b495cfc79bc 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -434,7 +434,8 @@  static void __init sev_map_percpu_data(void)
 {
 	int cpu;
 
-	if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+	if (cc_vendor != CC_VENDOR_AMD ||
+	    !cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
 		return;
 
 	for_each_possible_cpu(cpu) {