Messages in this thread | | | Subject | Re: [PATCH v5 06/15] x86/sev: Drop redundant and potentially misleading 'sev_enabled' | From | Paolo Bonzini <> | Date | Thu, 22 Apr 2021 14:05:46 +0200 |
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On 22/04/21 04:11, Sean Christopherson wrote: > 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>
Boris or another x86 maintainer, can you ack this small patch? We would like to use sev_enabled as a static variable in KVM.
Paolo
> --- > 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; > } >
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