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Code Issues Releases Wiki Activity

x86/sev: Drop redundant and potentially misleading 'sev_enabled'

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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 b57de6cd16 ("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>
Message-Id: <20210422021125.3417167-7-seanjc@google.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-04-21 19:11:16 -07:00 committed by Paolo Bonzini
parent 013380782d
commit 4daf2a1c45
3 changed files with 5 additions and 9 deletions
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1
arch/x86/include/asm/mem_encrypt.h
View file

@ -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,

12
arch/x86/mm/mem_encrypt.c
View file

@ -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 */

1
arch/x86/mm/mem_encrypt_identity.c
View file

@ -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;
}