[v4,00/14] KVM: SVM: Misc SEV cleanups

Message

Sean Christopherson March 6, 2021, 1:58 a.m. UTC

Minor bug fixes and refactorings of SEV related code, mainly to clean up
the KVM code for tracking whether or not SEV and SEV-ES are enabled.  E.g.
KVM has both sev_es and svm_sev_enabled(), and a global 'sev' flag while
also using 'sev' as a local variable in several places.

Based kvm/master, v5.12-rc1-dontuse.

v4:
 - Reinstate the patch to override CPUID.0x8000_001F.
 - Properly configure the CPUID.0x8000_001F override. [Paolo]
 - Rebase to v5.12-rc1-dontuse.
v3:
 - Drop two patches: add a dedicated feature word for CPUID_0x8000001F,
   and use the new word to mask host CPUID in KVM.  I'll send these as a
   separate mini-series so that Boris can take them through tip.
 - Add a patch to remove dependency on
   CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT. [Boris / Paolo]
 - Use kcalloc() instead of an open-coded equivalent. [Tom]
 - Nullify sev_asid_bitmap when freeing it during setup. [Tom]
 - Add a comment in sev_hardware_teardown() to document why it's safe to
   query the ASID bitmap without taking the lock. [Tom]
 - Collect reviews. [Tom and Brijesh]
v2:
 - Remove the kernel's sev_enabled instead of renaming it to sev_guest.
 - Fix various build issues. [Tom]
 - Remove stable tag from the patch to free sev_asid_bitmap.  Keeping the
   bitmap on failure is truly only a leak once svm_sev_enabled() is
   dropped later in the series.  It's still arguably a fix since KVM will
   unnecessarily keep memory, but it's not stable material. [Tom]
 - Collect one Ack. [Tom]

v1:
 - https://lkml.kernel.org/r/[e-mail]

Sean Christopherson (14):
  KVM: SVM: Zero out the VMCB array used to track SEV ASID association
  KVM: SVM: Free sev_asid_bitmap during init if SEV setup fails
  KVM: SVM: Move SEV module params/variables to sev.c
  KVM: x86: Do not advertise SME, VM_PAGE_FLUSH, or unknown features
  x86/sev: Drop redundant and potentially misleading 'sev_enabled'
  KVM: SVM: Append "_enabled" to module-scoped SEV/SEV-ES control
    variables
  KVM: SVM: Condition sev_enabled and sev_es_enabled on
    CONFIG_KVM_AMD_SEV=y
  KVM: SVM: Enable SEV/SEV-ES functionality by default (when supported)
  KVM: SVM: Unconditionally invoke sev_hardware_teardown()
  KVM: SVM: Explicitly check max SEV ASID during sev_hardware_setup()
  KVM: SVM: Move SEV VMCB tracking allocation to sev.c
  KVM: SVM: Drop redundant svm_sev_enabled() helper
  KVM: SVM: Remove an unnecessary prototype declaration of
    sev_flush_asids()
  KVM: SVM: Skip SEV cache flush if no ASIDs have been used

 arch/x86/include/asm/mem_encrypt.h |  1 -
 arch/x86/kvm/cpuid.c               |  6 +++
 arch/x86/kvm/cpuid.h               |  1 +
 arch/x86/kvm/svm/sev.c             | 72 +++++++++++++++++++++---------
 arch/x86/kvm/svm/svm.c             | 35 +++++----------
 arch/x86/kvm/svm/svm.h             |  8 +---
 arch/x86/mm/mem_encrypt.c          | 12 +++--
 arch/x86/mm/mem_encrypt_identity.c |  1 -
 8 files changed, 74 insertions(+), 62 deletions(-)