linux-kernel - [PATCH 0/2] KVM: x86/mmu: Fix TLB flushing bugs in TDP MMU

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Date:   Fri, 19 Mar 2021 16:20:04 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Ben Gardon <bgardon@...gle.com>
Subject: [PATCH 0/2] KVM: x86/mmu: Fix TLB flushing bugs in TDP MMU

Two bug fixes involving the TDP MMU.  Found by inspection while working on
a series to consolidate MMU notifier memslot walks across architectures,
which I'll hopefully post next week.

Patch 1 fixes a bug where KVM yields, e.g. due to lock contention, without
performing a pending TLB flush that was required from a previous root.

Patch 2 fixes a much more egregious bug where it fails to handle TDP MMU
flushes in NX huge page recovery, as well as a similar bug to patch 1
where KVM can yield without correctly handling a previously triggered
pending TLB flush.

Sean Christopherson (2):
  KVM: x86/mmu: Ensure TLBs are flushed when yielding during GFN range
    zap
  KVM: x86/mmu: Ensure TLBs are flushed when yielding during NX zapping

 arch/x86/kvm/mmu/mmu.c     | 15 ++++++++++-----
 arch/x86/kvm/mmu/tdp_mmu.c | 29 +++++++++++++++--------------
 arch/x86/kvm/mmu/tdp_mmu.h |  3 ++-
 3 files changed, 27 insertions(+), 20 deletions(-)

-- 
2.31.0.rc2.261.g7f71774620-goog