arm64: KVM: Introduce per-vcpu kvm device controls

In some cases it needs to get/set attributes specific to a vcpu and so
needs something else than ONE_REG.

Let's copy the KVM_DEVICE approach, and define the respective ioctls
for the vcpu file descriptor.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 9684f8d..cb2ef0b 100644 (file)
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2507,8 +2507,9 @@ struct kvm_create_device {
 
 4.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR
 
-Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device
-Type: device ioctl, vm ioctl
+Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device,
+  KVM_CAP_VCPU_ATTRIBUTES for vcpu device
+Type: device ioctl, vm ioctl, vcpu ioctl
 Parameters: struct kvm_device_attr
 Returns: 0 on success, -1 on error
 Errors:
@@ -2533,8 +2534,9 @@ struct kvm_device_attr {
 
 4.81 KVM_HAS_DEVICE_ATTR
 
-Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device
-Type: device ioctl, vm ioctl
+Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device,
+  KVM_CAP_VCPU_ATTRIBUTES for vcpu device
+Type: device ioctl, vm ioctl, vcpu ioctl
 Parameters: struct kvm_device_attr
 Returns: 0 on success, -1 on error
 Errors:

diff --git a/Documentation/virtual/kvm/devices/vcpu.txt b/Documentation/virtual/kvm/devices/vcpu.txt
new file mode 100644 (file)
index 0000000..3cc59c5
--- /dev/null
+++ b/Documentation/virtual/kvm/devices/vcpu.txt
@@ -0,0 +1,8 @@
+Generic vcpu interface
+====================================
+
+The virtual cpu "device" also accepts the ioctls KVM_SET_DEVICE_ATTR,
+KVM_GET_DEVICE_ATTR, and KVM_HAS_DEVICE_ATTR. The interface uses the same struct
+kvm_device_attr as other devices, but targets VCPU-wide settings and controls.
+
+The groups and attributes per virtual cpu, if any, are architecture specific.

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 9d133df..1662323 100644 (file)
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -828,11 +828,51 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
        return 0;
 }
 
+static int kvm_arm_vcpu_set_attr(struct kvm_vcpu *vcpu,
+                                struct kvm_device_attr *attr)
+{
+       int ret = -ENXIO;
+
+       switch (attr->group) {
+       default:
+               break;
+       }
+
+       return ret;
+}
+
+static int kvm_arm_vcpu_get_attr(struct kvm_vcpu *vcpu,
+                                struct kvm_device_attr *attr)
+{
+       int ret = -ENXIO;
+
+       switch (attr->group) {
+       default:
+               break;
+       }
+
+       return ret;
+}
+
+static int kvm_arm_vcpu_has_attr(struct kvm_vcpu *vcpu,
+                                struct kvm_device_attr *attr)
+{
+       int ret = -ENXIO;
+
+       switch (attr->group) {
+       default:
+               break;
+       }
+
+       return ret;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp,
                         unsigned int ioctl, unsigned long arg)
 {
        struct kvm_vcpu *vcpu = filp->private_data;
        void __user *argp = (void __user *)arg;
+       struct kvm_device_attr attr;
 
        switch (ioctl) {
        case KVM_ARM_VCPU_INIT: {
@@ -875,6 +915,21 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                        return -E2BIG;
                return kvm_arm_copy_reg_indices(vcpu, user_list->reg);
        }
+       case KVM_SET_DEVICE_ATTR: {
+               if (copy_from_user(&attr, argp, sizeof(attr)))
+                       return -EFAULT;
+               return kvm_arm_vcpu_set_attr(vcpu, &attr);
+       }
+       case KVM_GET_DEVICE_ATTR: {
+               if (copy_from_user(&attr, argp, sizeof(attr)))
+                       return -EFAULT;
+               return kvm_arm_vcpu_get_attr(vcpu, &attr);
+       }
+       case KVM_HAS_DEVICE_ATTR: {
+               if (copy_from_user(&attr, argp, sizeof(attr)))
+                       return -EFAULT;
+               return kvm_arm_vcpu_has_attr(vcpu, &attr);
+       }
        default:
                return -EINVAL;
        }

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index cf4f28a..9677bf0 100644 (file)
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -81,6 +81,7 @@ int kvm_arch_dev_ioctl_check_extension(long ext)
                r = kvm_arm_support_pmu_v3();
                break;
        case KVM_CAP_SET_GUEST_DEBUG:
+       case KVM_CAP_VCPU_ATTRIBUTES:
                r = 1;
                break;
        default:

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index dc16d30..50f44a2 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -851,6 +851,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_HYPERV_SYNIC 123
 #define KVM_CAP_S390_RI 124
 #define KVM_CAP_ARM_PMU_V3 125
+#define KVM_CAP_VCPU_ATTRIBUTES 126
 
 #ifdef KVM_CAP_IRQ_ROUTING