Re: [PATCH 06/13] x86/sev: Rename global "sev_enabled" flag to "sev_guest"

[Tom Lendacky]

On 1/11/21 10:02 AM, Tom Lendacky wrote:
> On 1/8/21 6:47 PM, Sean Christopherson wrote:
> > Use "guest" instead of "enabled" for the global "running as an SEV guest"
> > flag to avoid confusion over whether "sev_enabled" refers to the guest or
> > the host.  This will also allow KVM to usurp "sev_enabled" for its own
> > purposes.
> >
> > No functional change intended.
> >
> > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> Acked-by: Tom Lendacky <thomas.lendacky@xxxxxxx>

Ah, I tried building with CONFIG_KVM=y and CONFIG_KVM_AMD=y and got a 
build error:

In file included from arch/x86/kvm/svm/svm.c:43:
arch/x86/kvm/svm/svm.h:222:20: error: ‘sev_guest’ redeclared as different 
kind of symbol
  222 | static inline bool sev_guest(struct kvm *kvm)
      |                    ^~~~~~~~~
In file included from ./include/linux/mem_encrypt.h:17,
                 from ./arch/x86/include/asm/page_types.h:7,
                 from ./arch/x86/include/asm/page.h:9,
                 from ./arch/x86/include/asm/thread_info.h:12,
                 from ./include/linux/thread_info.h:38,
                 from ./arch/x86/include/asm/preempt.h:7,
                 from ./include/linux/preempt.h:78,
                 from ./include/linux/percpu.h:6,
                 from ./include/linux/context_tracking_state.h:5,
                 from ./include/linux/hardirq.h:5,
                 from ./include/linux/kvm_host.h:7,
                 from arch/x86/kvm/svm/svm.c:3:
./arch/x86/include/asm/mem_encrypt.h:23:13: note: previous declaration of 
‘sev_guest’ was here
   23 | extern bool sev_guest;
      |             ^~~~~~~~~

Thanks,
Tom

> > ---
> >   arch/x86/include/asm/mem_encrypt.h | 2 +-
> >   arch/x86/mm/mem_encrypt.c          | 4 ++--
> >   arch/x86/mm/mem_encrypt_identity.c | 2 +-
> >   3 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/mem_encrypt.h 
> > b/arch/x86/include/asm/mem_encrypt.h
> > index 2f62bbdd9d12..9b3990928674 100644
> > --- a/arch/x86/include/asm/mem_encrypt.h
> > +++ b/arch/x86/include/asm/mem_encrypt.h
> > @@ -20,7 +20,7 @@
> >   extern u64 sme_me_mask;
> >   extern u64 sev_status;
> > -extern bool sev_enabled;
> > +extern bool sev_guest;
> >   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..0f798355de03 100644
> > --- a/arch/x86/mm/mem_encrypt.c
> > +++ b/arch/x86/mm/mem_encrypt.c
> > @@ -44,7 +44,7 @@ EXPORT_SYMBOL(sme_me_mask);
> >   DEFINE_STATIC_KEY_FALSE(sev_enable_key);
> >   EXPORT_SYMBOL_GPL(sev_enable_key);
> > -bool sev_enabled __section(".data");
> > +bool sev_guest __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);
> > @@ -344,7 +344,7 @@ int __init early_set_memory_encrypted(unsigned long 
> > vaddr, unsigned long size)
> >    */
> >   bool sme_active(void)
> >   {
> > -    return sme_me_mask && !sev_enabled;
> > +    return sme_me_mask && !sev_guest;
> >   }
> >   bool sev_active(void)
> > diff --git a/arch/x86/mm/mem_encrypt_identity.c 
> > b/arch/x86/mm/mem_encrypt_identity.c
> > index 6c5eb6f3f14f..91b6b899c02b 100644
> > --- a/arch/x86/mm/mem_encrypt_identity.c
> > +++ b/arch/x86/mm/mem_encrypt_identity.c
> > @@ -545,7 +545,7 @@ 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;
> > +        sev_guest = true;
> >           physical_mask &= ~sme_me_mask;
> >           return;
> >       }