linux-kernel - [GIT PULL] KVM: x86: MMU changes for 6.18

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Message-ID: <20250927060910.2933942-4-seanjc@google.com>
Date: Fri, 26 Sep 2025 23:09:03 -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: MMU changes for 6.18

Recover TDP MMU NX huge pages under read lock, and fix two (interruptible)
deadlocks in prefaulting and in the TDX anti-zero-step code (there's a
selftest from Yan for the prefaulting case that I'll send along later).

The following changes since commit c17b750b3ad9f45f2b6f7e6f7f4679844244f0b9:

  Linux 6.17-rc2 (2025-08-17 15:22:10 -0700)

are available in the Git repository at:

  https://github.com/kvm-x86/linux.git tags/kvm-x86-mmu-6.18

for you to fetch changes up to 2bc2694fe20bf06eb73524426e3f4581d7b28923:

  KVM: TDX: Do not retry locally when the retry is caused by invalid memslot (2025-09-10 12:06:35 -0700)

----------------------------------------------------------------
KVM x86 MMU changes for 6.18

 - Recover possible NX huge pages within the TDP MMU under read lock to
   reduce guest jitter when restoring NX huge pages.

 - Return -EAGAIN during prefault if userspace concurrently deletes/moves the
   relevant memslot to fix an issue where prefaulting could deadlock with the
   memslot update.

 - Don't retry in TDX's anti-zero-step mitigation if the target memslot is
   invalid, i.e. is being deleted or moved, to fix a deadlock scenario similar
   to the aforementioned prefaulting case.

----------------------------------------------------------------
Sean Christopherson (2):
      KVM: x86/mmu: Return -EAGAIN if userspace deletes/moves memslot during prefault
      KVM: TDX: Do not retry locally when the retry is caused by invalid memslot

Vipin Sharma (3):
      KVM: x86/mmu: Track possible NX huge pages separately for TDP vs. Shadow MMU
      KVM: x86/mmu: Rename kvm_tdp_mmu_zap_sp() to better indicate its purpose
      KVM: x86/mmu: Recover TDP MMU NX huge pages using MMU read lock

 arch/x86/include/asm/kvm_host.h |  39 ++++++----
 arch/x86/kvm/mmu/mmu.c          | 165 ++++++++++++++++++++++++++--------------
 arch/x86/kvm/mmu/mmu_internal.h |   6 +-
 arch/x86/kvm/mmu/tdp_mmu.c      |  49 +++++++++---
 arch/x86/kvm/mmu/tdp_mmu.h      |   3 +-
 arch/x86/kvm/vmx/tdx.c          |  11 +++
 virt/kvm/kvm_main.c             |   1 +
 7 files changed, 192 insertions(+), 82 deletions(-)