[PATCH v5 00/15] KVM: SVM: Misc SEV cleanups

Sean Christopherson
2021-04-22T02:11:32Z

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/queue-ish, commit 0e91d1992235 ("KVM: SVM: Allocate SEV command
structures on local stack"), to avoid the conflicting CPUID.0x8000_001F
patch sitting in kvm/queue.

v5:
- Use Paolo's version of the CPUID.0x8000_001F patch, with some of my
goo on top. Paolo gets credit by introducing fewer bugs; v4 missed
the SEV/SEV-ES module params and used the wrong reverse-CPUID index...
- Add a patch to disable SEV/SEV-ES if NPT is disabled.
- Rebased, as above.
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/20210109004714.1341275-1-seanjc@google.com

Paolo Bonzini (1):
KVM: SEV: Mask CPUID[0x8000001F].eax according to supported features

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: Disable SEV/SEV-ES if NPT is disabled
KVM: SVM: Move SEV module params/variables to sev.c
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 | 8 ++-
arch/x86/kvm/cpuid.h | 1 +
arch/x86/kvm/svm/sev.c | 80 ++++++++++++++++++++++--------
arch/x86/kvm/svm/svm.c | 57 +++++++++------------
arch/x86/kvm/svm/svm.h | 9 +---
arch/x86/mm/mem_encrypt.c | 12 ++---
arch/x86/mm/mem_encrypt_identity.c | 1 -
8 files changed, 97 insertions(+), 72 deletions(-)