KVM: SVM: enhance info printk's in SEV init

Let's print available ASID ranges for SEV/SEV-ES guests.
This information can be useful for system administrator
to debug if SEV/SEV-ES fails to enable.

There are a few reasons.
SEV:
- NPT is disabled (module parameter)
- CPU lacks some features (sev, decodeassists)
- Maximum SEV ASID is 0

SEV-ES:
- mmio_caching is disabled (module parameter)
- CPU lacks sev_es feature
- Minimum SEV ASID value is 1 (can be adjusted in BIOS/UEFI)

==
   
KVM: SVM: free sev_*asid_bitmap init if SEV init fails

If misc_cg_set_capacity() fails for some reason then we have
a memleak for sev_reclaim_asid_bitmap/sev_asid_bitmap. It's
not a case right now, because misc_cg_set_capacity() just can't
fail and check inside it is always successful.

But let's fix that for code consistency.

Cc: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stéphane Graber <stgraber@ubuntu.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>

Alexander Mikhalitsyn (2):
  KVM: SVM: free sev_*asid_bitmap init if SEV init fails
  KVM: SVM: enhance info printk's in SEV init

 arch/x86/kvm/svm/sev.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

-- 
2.34.1

On Mon, 22 May 2023 18:12:46 +0200, Alexander Mikhalitsyn wrote:
> KVM: SVM: enhance info printk's in SEV init
> 
> Let's print available ASID ranges for SEV/SEV-ES guests.
> This information can be useful for system administrator
> to debug if SEV/SEV-ES fails to enable.
> 
> There are a few reasons.
> SEV:
> - NPT is disabled (module parameter)
> - CPU lacks some features (sev, decodeassists)
> - Maximum SEV ASID is 0
> 
> [...]

Applied [2/2] to kvm-x86 svm, with the minor fixup.  I'll post a formal patch
for the alternative approach to "fixing" the leak, I can always circle back to
this series if this approach is preferred.

Thanks!

[2/2] KVM: SVM: enhance info printk's in SEV init
      https://github.com/kvm-x86/linux/commit/6d1bc9754b04

--
https://github.com/kvm-x86/linux/tree/next
https://github.com/kvm-x86/linux/tree/fixes