diff options
author | Paolo Bonzini <pbonzini@redhat.com> | 2023-01-13 19:27:55 +0300 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-01-24 14:05:23 +0300 |
commit | dc7c31e922787466957cadf2c0ad21c0f9a4091f (patch) | |
tree | b6c6feeb812282a21d00ae59eaa69033b6c1078a /Documentation/virt/kvm/locking.rst | |
parent | edd731d73221277cb384efeb66da76dae0a68dfa (diff) | |
parent | 310bc39546a435c83cc27a0eba878afac0d74714 (diff) | |
download | linux-dc7c31e922787466957cadf2c0ad21c0f9a4091f.tar.xz |
Merge branch 'kvm-v6.2-rc4-fixes' into HEAD
ARM:
* Fix the PMCR_EL0 reset value after the PMU rework
* Correctly handle S2 fault triggered by a S1 page table walk
by not always classifying it as a write, as this breaks on
R/O memslots
* Document why we cannot exit with KVM_EXIT_MMIO when taking
a write fault from a S1 PTW on a R/O memslot
* Put the Apple M2 on the naughty list for not being able to
correctly implement the vgic SEIS feature, just like the M1
before it
* Reviewer updates: Alex is stepping down, replaced by Zenghui
x86:
* Fix various rare locking issues in Xen emulation and teach lockdep
to detect them
* Documentation improvements
* Do not return host topology information from KVM_GET_SUPPORTED_CPUID
Diffstat (limited to 'Documentation/virt/kvm/locking.rst')
-rw-r--r-- | Documentation/virt/kvm/locking.rst | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst index 1147836742cc..14c4e9fa501d 100644 --- a/Documentation/virt/kvm/locking.rst +++ b/Documentation/virt/kvm/locking.rst @@ -26,21 +26,22 @@ The acquisition orders for mutexes are as follows: For SRCU: -- ``synchronize_srcu(&kvm->srcu)`` is called _inside_ - the kvm->slots_lock critical section, therefore kvm->slots_lock - cannot be taken inside a kvm->srcu read-side critical section. - Instead, kvm->slots_arch_lock is released before the call - to ``synchronize_srcu()`` and _can_ be taken inside a - kvm->srcu read-side critical section. - -- kvm->lock is taken inside kvm->srcu, therefore - ``synchronize_srcu(&kvm->srcu)`` cannot be called inside - a kvm->lock critical section. If you cannot delay the - call until after kvm->lock is released, use ``call_srcu``. +- ``synchronize_srcu(&kvm->srcu)`` is called inside critical sections + for kvm->lock, vcpu->mutex and kvm->slots_lock. These locks _cannot_ + be taken inside a kvm->srcu read-side critical section; that is, the + following is broken:: + + srcu_read_lock(&kvm->srcu); + mutex_lock(&kvm->slots_lock); + +- kvm->slots_arch_lock instead is released before the call to + ``synchronize_srcu()``. It _can_ therefore be taken inside a + kvm->srcu read-side critical section, for example while processing + a vmexit. On x86: -- vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock +- vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock and kvm->arch.xen.xen_lock - kvm->arch.mmu_lock is an rwlock. kvm->arch.tdp_mmu_pages_lock and kvm->arch.mmu_unsync_pages_lock are taken inside kvm->arch.mmu_lock, and |