kvm: take srcu lock around kvm_steal_time_set_preempted()

kvm_memslots() will be called by kvm_write_guest_offset_cached() so
take the srcu lock.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8ce1139a08b5319f5f84b58dfc35b32518c20de9..445c51b6cf6dc702a0da9710ee5b6eb4b996ec34 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2844,6 +2844,7 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
+       int idx;
        /*
         * Disable page faults because we're in atomic context here.
         * kvm_write_guest_offset_cached() would call might_fault()
@@ -2853,7 +2854,13 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
         * paging.
         */
        pagefault_disable();
+       /*
+        * kvm_memslots() will be called by
+        * kvm_write_guest_offset_cached() so take the srcu lock.
+        */
+       idx = srcu_read_lock(&vcpu->kvm->srcu);
        kvm_steal_time_set_preempted(vcpu);
+       srcu_read_unlock(&vcpu->kvm->srcu, idx);
        pagefault_enable();
        kvm_x86_ops->vcpu_put(vcpu);
        kvm_put_guest_fpu(vcpu);