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authorBen Gardon <bgardon@google.com>2021-05-18 10:34:11 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2021-06-17 13:09:26 -0400
commitb10a038e84d188e15819058b2978b2daa9853aeb (patch)
tree6a3215a5a0ee02fcfd0e3da7fb1456d1a4756274 /Documentation/virt
parentddc12f2a12917c10b0deb0928f0560bffb7729ec (diff)
downloadlinux-b10a038e84d188e15819058b2978b2daa9853aeb.tar.bz2
KVM: mmu: Add slots_arch_lock for memslot arch fields
Add a new lock to protect the arch-specific fields of memslots if they need to be modified in a kvm->srcu read critical section. A future commit will use this lock to lazily allocate memslot rmaps for x86. Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20210518173414.450044-5-bgardon@google.com> [Add Documentation/ hunk. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virt')
-rw-r--r--Documentation/virt/kvm/locking.rst5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst
index 1fc860c007a3..35eca377543d 100644
--- a/Documentation/virt/kvm/locking.rst
+++ b/Documentation/virt/kvm/locking.rst
@@ -16,6 +16,11 @@ The acquisition orders for mutexes are as follows:
- kvm->slots_lock is taken outside kvm->irq_lock, though acquiring
them together is quite rare.
+- Unlike kvm->slots_lock, kvm->slots_arch_lock is released before
+ synchronize_srcu(&kvm->srcu). Therefore kvm->slots_arch_lock
+ can be taken inside a kvm->srcu read-side critical section,
+ while kvm->slots_lock cannot.
+
On x86:
- vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock