[PATCH 00/10] KVM: SVM: Attempt to cleanup SEV_FEATURES

[Sean Christopherson <seanjc@google.com>]

This is a hastily thrown together series, barely above RFC, to try and
address the worst of the issues that arise with guest controlled SEV
features (thanks AP creation)[1].

In addition to the initial flaws with DebugSwap, I came across a variety
of issues when trying to figure out how best to handle SEV features in
general.  E.g. AFAICT, KVM doesn't guard against userspace manually making
a vCPU RUNNABLE after it has been DESTROYED (or after a failed CREATE).

This is essentially compile-tested only, as I don't have easy access to a
system with SNP enabled.  I ran the SEV-ES selftests, but that's not much
in the way of test coverage.

AMD folks, I would greatly appreciate reviews, testing, and most importantly,
confirmation that all of this actually works the way I think it does.

[1] https://lore.kernel.org/all/Z7TSef290IQxQhT2@google.com

Sean Christopherson (10):
  KVM: SVM: Save host DR masks but NOT DRs on CPUs with DebugSwap
  KVM: SVM: Don't rely on DebugSwap to restore host DR0..DR3
  KVM: SVM: Terminate the VM if a SEV-ES+ guest is run with an invalid
    VMSA
  KVM: SVM: Don't change target vCPU state on AP Creation VMGEXIT error
  KVM: SVM: Require AP's "requested" SEV_FEATURES to match KVM's view
  KVM: SVM: Simplify request+kick logic in SNP AP Creation handling
  KVM: SVM: Use guard(mutex) to simplify SNP AP Creation error handling
  KVM: SVM: Mark VMCB dirty before processing incoming snp_vmsa_gpa
  KVM: SVM: Use guard(mutex) to simplify SNP vCPU state updates
  KVM: SVM: Invalidate "next" SNP VMSA GPA even on failure

 arch/x86/kvm/svm/sev.c | 218 +++++++++++++++++++----------------------
 arch/x86/kvm/svm/svm.c |   7 +-
 arch/x86/kvm/svm/svm.h |   2 +-
 3 files changed, 106 insertions(+), 121 deletions(-)


base-commit: fed48e2967f402f561d80075a20c5c9e16866e53
-- 
2.48.1.601.g30ceb7b040-goog