KVM: PPC: Book3S: Take the kvm->srcu lock in kvmppc_h_logical_ci_load/store()

Access to the kvm->buses (like with the kvm_io_bus_read() and -write()
functions) has to be protected via the kvm->srcu lock.
The kvmppc_h_logical_ci_load() and -store() functions are missing
this lock so far, so let's add it there, too.
This fixes the problem that the kernel reports "suspicious RCU usage"
when lock debugging is enabled.

Cc: stable@vger.kernel.org # v4.1+
Fixes: 99342cf8044420eebdf9297ca03a14cb6a7085a1
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index cf009167d208db3ebf3d74a2e1f29b3bfb091d26..099c79d8c160fd59c2d0e28217c1348f03c08cbf 100644 (file)
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -829,12 +829,15 @@ int kvmppc_h_logical_ci_load(struct kvm_vcpu *vcpu)
        unsigned long size = kvmppc_get_gpr(vcpu, 4);
        unsigned long addr = kvmppc_get_gpr(vcpu, 5);
        u64 buf;
+       int srcu_idx;
        int ret;
 
        if (!is_power_of_2(size) || (size > sizeof(buf)))
                return H_TOO_HARD;
 
+       srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
        ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, addr, size, &buf);
+       srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
        if (ret != 0)
                return H_TOO_HARD;
 
@@ -869,6 +872,7 @@ int kvmppc_h_logical_ci_store(struct kvm_vcpu *vcpu)
        unsigned long addr = kvmppc_get_gpr(vcpu, 5);
        unsigned long val = kvmppc_get_gpr(vcpu, 6);
        u64 buf;
+       int srcu_idx;
        int ret;
 
        switch (size) {
@@ -892,7 +896,9 @@ int kvmppc_h_logical_ci_store(struct kvm_vcpu *vcpu)
                return H_TOO_HARD;
        }
 
+       srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
        ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, addr, size, &buf);
+       srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
        if (ret != 0)
                return H_TOO_HARD;