linux-kernel - [PATCH 0/2] KVM: x86/mmu: Fix unsync races within TDP MMU

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Message-Id: <20210810224554.2978735-1-seanjc@google.com>
Date:   Tue, 10 Aug 2021 15:45:52 -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 unsync races within TDP MMU

Patch 1 fixes a bug where concurrent TDP MMU page faults can "corrupt" the
unsync shadow page fields, notably unsync_children, as the TDP MMU holds
mmu_lock for read and the unsync logic is not thread safe.

Patch 2 is a tangentially related cleanup.

Sean Christopherson (2):
  KVM: x86/mmu: Protect marking SPs unsync when using TDP MMU with
    spinlock
  KVM: x86/mmu: Drop 'shared' param from tdp_mmu_link_page()

 Documentation/virt/kvm/locking.rst |  8 +++----
 arch/x86/include/asm/kvm_host.h    |  3 +++
 arch/x86/kvm/mmu/mmu.c             | 36 ++++++++++++++++++++++++++++--
 arch/x86/kvm/mmu/mmu_internal.h    |  3 ++-
 arch/x86/kvm/mmu/spte.c            |  4 ++--
 arch/x86/kvm/mmu/spte.h            |  2 +-
 arch/x86/kvm/mmu/tdp_mmu.c         | 20 +++++------------
 7 files changed, 52 insertions(+), 24 deletions(-)

-- 
2.32.0.605.g8dce9f2422-goog