[PATCH v2 06/14] x86/sev: Drop redundant and potentially misleading 'sev_enabled'

Sean Christopherson
2021-01-14T00:43:35Z

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.

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 2f62bbdd9d12..88d624499411 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 bc0833713be9..b89bc03c63a2 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);

@@ -342,16 +340,16 @@ 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();
+}
+
/* Needs to be called from non-instrumentable code */
bool noinstr sev_es_active(void)
{
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;
}
--
2.30.0.284.gd98b1dd5eaa7-goog