[tip: x86/sev] x86/mm: Fix memory encryption features advertisement

From: tip-bot2 for Kirill A. Shutemov
Date: Wed Jan 24 2024 - 16:38:47 EST


The following commit has been merged into the x86/sev branch of tip:

Commit-ID: 0410516aaef4bf08030845547fb94f4ff989fac0
Gitweb: https://git.kernel.org/tip/0410516aaef4bf08030845547fb94f4ff989fac0
Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 24 Jan 2024 16:02:16 +02:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Wed, 24 Jan 2024 22:27:59 +01:00

x86/mm: Fix memory encryption features advertisement

When memory encryption is enabled, the kernel prints the encryption
flavor that the system supports.

The check assumes that everything is AMD SME/SEV if it doesn't have
the TDX CPU feature set.

Hyper-V vTOM sets cc_vendor to CC_VENDOR_INTEL when it runs as L2 guest
on top of TDX, but not X86_FEATURE_TDX_GUEST. Hyper-V only needs memory
encryption enabled for I/O without the rest of CoCo enabling.

To avoid confusion, check the cc_vendor directly.

[ bp: Massage commit message. ]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Jeremi Piotrowski <jpiotrowski@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
Acked-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Acked-by: Kai Huang <kai.huang@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240124140217.533748-1-kirill.shutemov@xxxxxxxxxxxxxxx
---
arch/x86/mm/mem_encrypt.c | 56 ++++++++++++++++++++------------------
1 file changed, 30 insertions(+), 26 deletions(-)

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index c290c55..d035bce 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -42,38 +42,42 @@ bool force_dma_unencrypted(struct device *dev)

static void print_mem_encrypt_feature_info(void)
{
- pr_info("Memory Encryption Features active:");
+ pr_info("Memory Encryption Features active: ");

- if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) {
- pr_cont(" Intel TDX\n");
- return;
- }
-
- pr_cont(" AMD");
+ switch (cc_vendor) {
+ case CC_VENDOR_INTEL:
+ pr_cont("Intel TDX\n");
+ break;
+ case CC_VENDOR_AMD:
+ pr_cont("AMD");

- /* Secure Memory Encryption */
- if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
+ /* Secure Memory Encryption */
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
/*
* SME is mutually exclusive with any of the SEV
* features below.
- */
- pr_cont(" SME\n");
- return;
+ */
+ pr_cont(" SME\n");
+ return;
+ }
+
+ /* Secure Encrypted Virtualization */
+ if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+ pr_cont(" SEV");
+
+ /* Encrypted Register State */
+ if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
+ pr_cont(" SEV-ES");
+
+ /* Secure Nested Paging */
+ if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+ pr_cont(" SEV-SNP");
+
+ pr_cont("\n");
+ break;
+ default:
+ pr_cont("Unknown\n");
}
-
- /* Secure Encrypted Virtualization */
- if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
- pr_cont(" SEV");
-
- /* Encrypted Register State */
- if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
- pr_cont(" SEV-ES");
-
- /* Secure Nested Paging */
- if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
- pr_cont(" SEV-SNP");
-
- pr_cont("\n");
}

/* Architecture __weak replacement functions */