linux-kernel - [PATCH 00/10] KVM: SVM: Attempt to cleanup SEV

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Message-ID: <20250219012705.1495231-1-seanjc@google.com>
Date: Tue, 18 Feb 2025 17:26:55 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Naveen N Rao <naveen@...nel.org>, Kim Phillips <kim.phillips@....com>, 
	Tom Lendacky <thomas.lendacky@....com>, Alexey Kardashevskiy <aik@....com>
Subject: [PATCH 00/10] KVM: SVM: Attempt to cleanup SEV_FEATURES

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