KVM: ARM: Introduce KVM_ARM_SET_DEVICE_ADDR ioctl
On ARM some bits are specific to the model being emulated for the guest and
user space needs a way to tell the kernel about those bits. An example is mmio
device base addresses, where KVM must know the base address for a given device
to properly emulate mmio accesses within a certain address range or directly
map a device with virtualiation extensions into the guest address space.
We make this API ARM-specific as we haven't yet reached a consensus for a
generic API for all KVM architectures that will allow us to do something like
this.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index c25439a..4505f86 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2210,6 +2210,43 @@
KVM_GET_ONE_REG/KVM_SET_ONE_REG calls.
+4.80 KVM_ARM_SET_DEVICE_ADDR
+
+Capability: KVM_CAP_ARM_SET_DEVICE_ADDR
+Architectures: arm
+Type: vm ioctl
+Parameters: struct kvm_arm_device_address (in)
+Returns: 0 on success, -1 on error
+Errors:
+ ENODEV: The device id is unknown
+ ENXIO: Device not supported on current system
+ EEXIST: Address already set
+ E2BIG: Address outside guest physical address space
+
+struct kvm_arm_device_addr {
+ __u64 id;
+ __u64 addr;
+};
+
+Specify a device address in the guest's physical address space where guests
+can access emulated or directly exposed devices, which the host kernel needs
+to know about. The id field is an architecture specific identifier for a
+specific device.
+
+ARM divides the id field into two parts, a device id and an address type id
+specific to the individual device.
+
+ bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 |
+ field: | 0x00000000 | device id | addr type id |
+
+ARM currently only require this when using the in-kernel GIC support for the
+hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 as the device id. When
+setting the base address for the guest's mapping of the VGIC virtual CPU
+and distributor interface, the ioctl must be called after calling
+KVM_CREATE_IRQCHIP, but before calling KVM_RUN on any of the VCPUs. Calling
+this ioctl twice for any of the base addresses will return -EEXIST.
+
+
5. The kvm_run structure
------------------------
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index 3303ff5..346ac3f 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -65,6 +65,19 @@
#define KVM_ARM_TARGET_CORTEX_A15 0
#define KVM_ARM_NUM_TARGETS 1
+/* KVM_ARM_SET_DEVICE_ADDR ioctl id encoding */
+#define KVM_ARM_DEVICE_TYPE_SHIFT 0
+#define KVM_ARM_DEVICE_TYPE_MASK (0xffff << KVM_ARM_DEVICE_TYPE_SHIFT)
+#define KVM_ARM_DEVICE_ID_SHIFT 16
+#define KVM_ARM_DEVICE_ID_MASK (0xffff << KVM_ARM_DEVICE_ID_SHIFT)
+
+/* Supported device IDs */
+#define KVM_ARM_DEVICE_VGIC_V2 0
+
+/* Supported VGIC address types */
+#define KVM_VGIC_V2_ADDR_TYPE_DIST 0
+#define KVM_VGIC_V2_ADDR_TYPE_CPU 1
+
#define KVM_ARM_VCPU_POWER_OFF 0 /* CPU is started in OFF state */
struct kvm_vcpu_init {
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 2d30e3a..523f77a 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -167,6 +167,8 @@
case KVM_CAP_COALESCED_MMIO:
r = KVM_COALESCED_MMIO_PAGE_OFFSET;
break;
+ case KVM_CAP_ARM_SET_DEVICE_ADDR:
+ r = 1;
case KVM_CAP_NR_VCPUS:
r = num_online_cpus();
break;
@@ -827,10 +829,29 @@
return -EINVAL;
}
+static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
+ struct kvm_arm_device_addr *dev_addr)
+{
+ return -ENODEV;
+}
+
long kvm_arch_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
- return -EINVAL;
+ struct kvm *kvm = filp->private_data;
+ void __user *argp = (void __user *)arg;
+
+ switch (ioctl) {
+ case KVM_ARM_SET_DEVICE_ADDR: {
+ struct kvm_arm_device_addr dev_addr;
+
+ if (copy_from_user(&dev_addr, argp, sizeof(dev_addr)))
+ return -EFAULT;
+ return kvm_vm_ioctl_set_device_addr(kvm, &dev_addr);
+ }
+ default:
+ return -EINVAL;
+ }
}
static void cpu_init_hyp_mode(void *vector)
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 7f2360a..c70577c 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -637,6 +637,7 @@
#define KVM_CAP_PPC_BOOKE_WATCHDOG 83
#define KVM_CAP_PPC_HTAB_FD 84
#define KVM_CAP_ARM_PSCI 87
+#define KVM_CAP_ARM_SET_DEVICE_ADDR 88
#ifdef KVM_CAP_IRQ_ROUTING
@@ -784,6 +785,11 @@
__u8 pad[16];
};
+struct kvm_arm_device_addr {
+ __u64 id;
+ __u64 addr;
+};
+
/*
* ioctls for VM fds
*/
@@ -869,6 +875,8 @@
#define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma)
/* Available with KVM_CAP_PPC_HTAB_FD */
#define KVM_PPC_GET_HTAB_FD _IOW(KVMIO, 0xaa, struct kvm_get_htab_fd)
+/* Available with KVM_CAP_ARM_SET_DEVICE_ADDR */
+#define KVM_ARM_SET_DEVICE_ADDR _IOW(KVMIO, 0xab, struct kvm_arm_device_addr)
/*
* ioctls for vcpu fds