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-rw-r--r--virt/kvm/arm/vgic/vgic-kvm-device.c100
1 files changed, 73 insertions, 27 deletions
diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index 1813f93b5cde..19fa331f2d11 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -233,6 +233,67 @@ int kvm_register_vgic_device(unsigned long type)
return ret;
}
+struct vgic_reg_attr {
+ struct kvm_vcpu *vcpu;
+ gpa_t addr;
+};
+
+static int parse_vgic_v2_attr(struct kvm_device *dev,
+ struct kvm_device_attr *attr,
+ struct vgic_reg_attr *reg_attr)
+{
+ int cpuid;
+
+ cpuid = (attr->attr & KVM_DEV_ARM_VGIC_CPUID_MASK) >>
+ KVM_DEV_ARM_VGIC_CPUID_SHIFT;
+
+ if (cpuid >= atomic_read(&dev->kvm->online_vcpus))
+ return -EINVAL;
+
+ reg_attr->vcpu = kvm_get_vcpu(dev->kvm, cpuid);
+ reg_attr->addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
+
+ return 0;
+}
+
+/* unlocks vcpus from @vcpu_lock_idx and smaller */
+static void unlock_vcpus(struct kvm *kvm, int vcpu_lock_idx)
+{
+ struct kvm_vcpu *tmp_vcpu;
+
+ for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
+ tmp_vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
+ mutex_unlock(&tmp_vcpu->mutex);
+ }
+}
+
+static void unlock_all_vcpus(struct kvm *kvm)
+{
+ unlock_vcpus(kvm, atomic_read(&kvm->online_vcpus) - 1);
+}
+
+/* Returns true if all vcpus were locked, false otherwise */
+static bool lock_all_vcpus(struct kvm *kvm)
+{
+ struct kvm_vcpu *tmp_vcpu;
+ int c;
+
+ /*
+ * Any time a vcpu is run, vcpu_load is called which tries to grab the
+ * vcpu->mutex. By grabbing the vcpu->mutex of all VCPUs we ensure
+ * that no other VCPUs are run and fiddle with the vgic state while we
+ * access it.
+ */
+ kvm_for_each_vcpu(c, tmp_vcpu, kvm) {
+ if (!mutex_trylock(&tmp_vcpu->mutex)) {
+ unlock_vcpus(kvm, c - 1);
+ return false;
+ }
+ }
+
+ return true;
+}
+
/** vgic_attr_regs_access: allows user space to read/write VGIC registers
*
* @dev: kvm device handle
@@ -245,15 +306,17 @@ static int vgic_attr_regs_access(struct kvm_device *dev,
struct kvm_device_attr *attr,
u32 *reg, bool is_write)
{
+ struct vgic_reg_attr reg_attr;
gpa_t addr;
- int cpuid, ret, c;
- struct kvm_vcpu *vcpu, *tmp_vcpu;
- int vcpu_lock_idx = -1;
+ struct kvm_vcpu *vcpu;
+ int ret;
- cpuid = (attr->attr & KVM_DEV_ARM_VGIC_CPUID_MASK) >>
- KVM_DEV_ARM_VGIC_CPUID_SHIFT;
- vcpu = kvm_get_vcpu(dev->kvm, cpuid);
- addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
+ ret = parse_vgic_v2_attr(dev, attr, &reg_attr);
+ if (ret)
+ return ret;
+
+ vcpu = reg_attr.vcpu;
+ addr = reg_attr.addr;
mutex_lock(&dev->kvm->lock);
@@ -261,24 +324,11 @@ static int vgic_attr_regs_access(struct kvm_device *dev,
if (ret)
goto out;
- if (cpuid >= atomic_read(&dev->kvm->online_vcpus)) {
- ret = -EINVAL;
+ if (!lock_all_vcpus(dev->kvm)) {
+ ret = -EBUSY;
goto out;
}
- /*
- * Any time a vcpu is run, vcpu_load is called which tries to grab the
- * vcpu->mutex. By grabbing the vcpu->mutex of all VCPUs we ensure
- * that no other VCPUs are run and fiddle with the vgic state while we
- * access it.
- */
- ret = -EBUSY;
- kvm_for_each_vcpu(c, tmp_vcpu, dev->kvm) {
- if (!mutex_trylock(&tmp_vcpu->mutex))
- goto out;
- vcpu_lock_idx = c;
- }
-
switch (attr->group) {
case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, reg);
@@ -291,12 +341,8 @@ static int vgic_attr_regs_access(struct kvm_device *dev,
break;
}
+ unlock_all_vcpus(dev->kvm);
out:
- for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
- tmp_vcpu = kvm_get_vcpu(dev->kvm, vcpu_lock_idx);
- mutex_unlock(&tmp_vcpu->mutex);
- }
-
mutex_unlock(&dev->kvm->lock);
return ret;
}