linux-kernel - [PATCH] x86/sev: mem_encrypt_free_decrypted_mem(): encrypt the pages for AMD SME only

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Date:   Sun, 27 Nov 2022 17:28:52 -0800
From:   Dexuan Cui <decui@...rosoft.com>
To:     dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        hpa@...or.com, brijesh.singh@....com
Cc:     linux-kernel@...r.kernel.org, linux-hyperv@...r.kernel.org,
        Dexuan Cui <decui@...rosoft.com>
Subject: [PATCH] x86/sev: mem_encrypt_free_decrypted_mem(): encrypt the pages for AMD SME only

sme_postprocess_startup() marks the __start_bss_decrypted pages shared
for AMD SME only, so here set_memory_encrypted() should be called for AMD
SME only, i.e. don't call the set_memory_encrypted() for TDX, otherwise the
error "failed to free unused decrypted pages" appears in 'dmesg'.

Fixes: b3f0907c71e0 ("x86/mm: Add .bss..decrypted section to hold shared variables")
Signed-off-by: Dexuan Cui <decui@...rosoft.com>
---
 arch/x86/mm/mem_encrypt_amd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 9c4d8dbcb129..fd9b58402a22 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -516,7 +516,7 @@ void __init mem_encrypt_free_decrypted_mem(void)
 	 * The unused memory range was mapped decrypted, change the encryption
 	 * attribute from decrypted to encrypted before freeing it.
 	 */
-	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
+	if (sme_me_mask && cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
 		r = set_memory_encrypted(vaddr, npages);
 		if (r) {
 			pr_warn("failed to free unused decrypted pages\n");
-- 
2.25.1