[PATCH v4 05/14] x86/sev: Drop redundant and potentially misleading 'sev_enabled'

From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Borislav Petkov <bp@suse.de>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH v4 05/14] x86/sev: Drop redundant and potentially misleading 'sev_enabled'
Date: Fri,  5 Mar 2021 17:58:56 -0800	[thread overview]
Message-ID: <20210306015905.186698-6-seanjc@google.com> (raw)
In-Reply-To: <20210306015905.186698-1-seanjc@google.com>

Drop the sev_enabled flag and switch its one user over to sev_active().
sev_enabled was made redundant with the introduction of sev_status in
commit b57de6cd1639 ("x86/sev-es: Add SEV-ES Feature Detection").
sev_enabled and sev_active() are guaranteed to be equivalent, as each is
true iff 'sev_status & MSR_AMD64_SEV_ENABLED' is true, and are only ever
written in tandem (ignoring compressed boot's version of sev_status).

Removing sev_enabled avoids confusion over whether it refers to the guest
or the host, and will also allow KVM to usurp "sev_enabled" for its own
purposes.

No functional change intended.

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/mem_encrypt.h |  1 -
 arch/x86/mm/mem_encrypt.c          | 12 +++++-------
 arch/x86/mm/mem_encrypt_identity.c |  1 -
 3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 31c4df123aa0..9c80c68d75b5 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -20,7 +20,6 @@
 
 extern u64 sme_me_mask;
 extern u64 sev_status;
-extern bool sev_enabled;
 
 void sme_encrypt_execute(unsigned long encrypted_kernel_vaddr,
 			 unsigned long decrypted_kernel_vaddr,
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 4b01f7dbaf30..be384d8d0543 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -44,8 +44,6 @@ EXPORT_SYMBOL(sme_me_mask);
 DEFINE_STATIC_KEY_FALSE(sev_enable_key);
 EXPORT_SYMBOL_GPL(sev_enable_key);
 
-bool sev_enabled __section(".data");
-
 /* Buffer used for early in-place encryption by BSP, no locking needed */
 static char sme_early_buffer[PAGE_SIZE] __initdata __aligned(PAGE_SIZE);
 
@@ -373,15 +371,15 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
  * up under SME the trampoline area cannot be encrypted, whereas under SEV
  * the trampoline area must be encrypted.
  */
-bool sme_active(void)
-{
-	return sme_me_mask && !sev_enabled;
-}
-
 bool sev_active(void)
 {
 	return sev_status & MSR_AMD64_SEV_ENABLED;
 }
+
+bool sme_active(void)
+{
+	return sme_me_mask && !sev_active();
+}
 EXPORT_SYMBOL_GPL(sev_active);
 
 /* Needs to be called from non-instrumentable code */
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index 6c5eb6f3f14f..0c2759b7f03a 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -545,7 +545,6 @@ void __init sme_enable(struct boot_params *bp)
 
 		/* SEV state cannot be controlled by a command line option */
 		sme_me_mask = me_mask;
-		sev_enabled = true;
 		physical_mask &= ~sme_me_mask;
 		return;
 	}
-- 
2.30.1.766.gb4fecdf3b7-goog

