diff options
| author |   Ben Gardon <bgardon@google.com> | 2021-02-02 10:57:26 -0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2021-02-04 05:27:44 -0500 |
| commit | 9a77daacc87dee9fd63e31243f21894132ed8407 (patch) | |
| tree | 1286e1602eb7e55325e92b8cb8565f72587e7064 /Documentation/virt/kvm/locking.rst | |
| parent | KVM: x86/mmu: Factor out functions to add/remove TDP MMU pages (diff) | |
| download | linux-dev-9a77daacc87dee9fd63e31243f21894132ed8407.tar.xz linux-dev-9a77daacc87dee9fd63e31243f21894132ed8407.zip | |
KVM: x86/mmu: Use atomic ops to set SPTEs in TDP MMU map
To prepare for handling page faults in parallel, change the TDP MMU
page fault handler to use atomic operations to set SPTEs so that changes
are not lost if multiple threads attempt to modify the same SPTE.
Reviewed-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210202185734.1680553-21-bgardon@google.com>
[Document new locking rules. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virt/kvm/locking.rst')
| -rw-r--r-- | Documentation/virt/kvm/locking.rst | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst index b21a34c34a21..0aa4817b466d 100644 --- a/Documentation/virt/kvm/locking.rst +++ b/Documentation/virt/kvm/locking.rst @@ -16,7 +16,14 @@ The acquisition orders for mutexes are as follows: - kvm->slots_lock is taken outside kvm->irq_lock, though acquiring them together is quite rare. -On x86, vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock. +On x86: + +- vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock + +- kvm->arch.mmu_lock is an rwlock. kvm->arch.tdp_mmu_pages_lock is + taken inside kvm->arch.mmu_lock, and cannot be taken without already + holding kvm->arch.mmu_lock (typically with ``read_lock``, otherwise + there's no need to take kvm->arch.tdp_mmu_pages_lock at all). Everything else is a leaf: no other lock is taken inside the critical sections. |