linux-kernel - [GIT PULL] KVM: x86: SEV changes for 6.17

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Message-ID: <20250725220713.264711-11-seanjc@google.com>
Date: Fri, 25 Jul 2025 15:07:10 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Sean Christopherson <seanjc@...gle.com>
Subject: [GIT PULL] KVM: x86: SEV changes for 6.17

Note!  This pull request is based on tags/x86_core_for_kvm from the tip tree.
Unless you merge that first (I don't think you'll do that?), merging this will
also suck in:

  4fdc3431e03b x86/lib: Add WBINVD and WBNOINVD helpers to target multiple CPUs
  07f99c3fbe6e x86/lib: Add WBNOINVD helper functions
  e638081751a2 x86/lib: Drop the unused return value from wbinvd_on_all_cpus()
  1d738dbb252f drm/gpu: Remove dead checks on wbinvd_on_all_cpus()'s return value

Holler if you want the full diff stat, or if you want me to handle dependencies
like this differently in the future.

The following changes since commit 4fdc3431e03b9c11803f399f91837fca487029a1:

  x86/lib: Add WBINVD and WBNOINVD helpers to target multiple CPUs (2025-07-10 13:30:17 +0200)

are available in the Git repository at:

  https://github.com/kvm-x86/linux.git tags/kvm-x86-sev-6.17

for you to fetch changes up to 6f38f8c574642a822f2e85f079fa29a49176c49c:

  KVM: SVM: Flush cache only on CPUs running SEV guest (2025-07-14 15:14:02 -0700)

----------------------------------------------------------------
KVM SEV cache maintenance changes for 6.17

 - Drop a superfluous WBINVD (on all CPUs!) when destroying a VM.

 - Use WBNOINVD instead of WBINVD when possible, for SEV cache maintenance,
   e.g. to minimize collateral damage when reclaiming memory from an SEV guest.

 - When reclaiming memory from an SEV guest, only do cache flushes on CPUs that
   have ever run a vCPU for the guest, i.e. don't flush the caches for CPUs
   that can't possibly have cache lines with dirty, encrypted data.

----------------------------------------------------------------
Kevin Loughlin (1):
      KVM: SEV: Prefer WBNOINVD over WBINVD for cache maintenance efficiency

Sean Christopherson (1):
      KVM: x86: Use wbinvd_on_cpu() instead of an open-coded equivalent

Zheyun Shen (2):
      KVM: SVM: Remove wbinvd in sev_vm_destroy()
      KVM: SVM: Flush cache only on CPUs running SEV guest

 arch/x86/kvm/svm/sev.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------
 arch/x86/kvm/svm/svm.h |   1 +
 arch/x86/kvm/x86.c     |   8 +-------
 3 files changed, 84 insertions(+), 35 deletions(-)