kvm/ppc: Hold srcu lock when calling kvm_io_bus_read/write

These functions do an srcu_dereference without acquiring the srcu lock
themselves.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 31084c6..270773f 100644 (file)
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -622,6 +622,8 @@ static void kvmppc_complete_mmio_load(struct kvm_vcpu *vcpu,
 int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
                        unsigned int rt, unsigned int bytes, int is_bigendian)
 {
+       int idx, ret;
+
        if (bytes > sizeof(run->mmio.data)) {
                printk(KERN_ERR "%s: bad MMIO length: %d\n", __func__,
                       run->mmio.len);
@@ -637,8 +639,14 @@ int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
        vcpu->mmio_is_write = 0;
        vcpu->arch.mmio_sign_extend = 0;
 
-       if (!kvm_io_bus_read(vcpu->kvm, KVM_MMIO_BUS, run->mmio.phys_addr,
-                            bytes, &run->mmio.data)) {
+       idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+       ret = kvm_io_bus_read(vcpu->kvm, KVM_MMIO_BUS, run->mmio.phys_addr,
+                             bytes, &run->mmio.data);
+
+       srcu_read_unlock(&vcpu->kvm->srcu, idx);
+
+       if (!ret) {
                kvmppc_complete_mmio_load(vcpu, run);
                vcpu->mmio_needed = 0;
                return EMULATE_DONE;
@@ -663,6 +671,7 @@ int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
                         u64 val, unsigned int bytes, int is_bigendian)
 {
        void *data = run->mmio.data;
+       int idx, ret;
 
        if (bytes > sizeof(run->mmio.data)) {
                printk(KERN_ERR "%s: bad MMIO length: %d\n", __func__,
@@ -692,8 +701,14 @@ int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
                }
        }
 
-       if (!kvm_io_bus_write(vcpu->kvm, KVM_MMIO_BUS, run->mmio.phys_addr,
-                             bytes, &run->mmio.data)) {
+       idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+       ret = kvm_io_bus_write(vcpu->kvm, KVM_MMIO_BUS, run->mmio.phys_addr,
+                              bytes, &run->mmio.data);
+
+       srcu_read_unlock(&vcpu->kvm->srcu, idx);
+
+       if (!ret) {
                vcpu->mmio_needed = 0;
                return EMULATE_DONE;
        }