KVM: arm/arm64: vgic-new: vgic_kvm_device: implement kvm_vgic_addr

kvm_vgic_addr is used by the userspace to set the base address of
the following register regions, as seen by the guest:
- distributor(v2 and v3),
- re-distributors (v3),
- CPU interface (v2).

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

2 files changed, 89 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index e153f12..082829a 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -16,10 +16,96 @@
 #include <linux/kvm_host.h>
 #include <kvm/arm_vgic.h>
 #include <linux/uaccess.h>
+#include <asm/kvm_mmu.h>
 #include "vgic.h"
 
 /* common helpers */
 
+static int vgic_check_ioaddr(struct kvm *kvm, phys_addr_t *ioaddr,
+			     phys_addr_t addr, phys_addr_t alignment)
+{
+	if (addr & ~KVM_PHYS_MASK)
+		return -E2BIG;
+
+	if (!IS_ALIGNED(addr, alignment))
+		return -EINVAL;
+
+	if (!IS_VGIC_ADDR_UNDEF(*ioaddr))
+		return -EEXIST;
+
+	return 0;
+}
+
+/**
+ * kvm_vgic_addr - set or get vgic VM base addresses
+ * @kvm:   pointer to the vm struct
+ * @type:  the VGIC addr type, one of KVM_VGIC_V[23]_ADDR_TYPE_XXX
+ * @addr:  pointer to address value
+ * @write: if true set the address in the VM address space, if false read the
+ *          address
+ *
+ * Set or get the vgic base addresses for the distributor and the virtual CPU
+ * interface in the VM physical address space.  These addresses are properties
+ * of the emulated core/SoC and therefore user space initially knows this
+ * information.
+ * Check them for sanity (alignment, double assignment). We can't check for
+ * overlapping regions in case of a virtual GICv3 here, since we don't know
+ * the number of VCPUs yet, so we defer this check to map_resources().
+ */
+int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
+{
+	int r = 0;
+	struct vgic_dist *vgic = &kvm->arch.vgic;
+	int type_needed;
+	phys_addr_t *addr_ptr, alignment;
+
+	mutex_lock(&kvm->lock);
+	switch (type) {
+	case KVM_VGIC_V2_ADDR_TYPE_DIST:
+		type_needed = KVM_DEV_TYPE_ARM_VGIC_V2;
+		addr_ptr = &vgic->vgic_dist_base;
+		alignment = SZ_4K;
+		break;
+	case KVM_VGIC_V2_ADDR_TYPE_CPU:
+		type_needed = KVM_DEV_TYPE_ARM_VGIC_V2;
+		addr_ptr = &vgic->vgic_cpu_base;
+		alignment = SZ_4K;
+		break;
+#ifdef CONFIG_KVM_ARM_VGIC_V3
+	case KVM_VGIC_V3_ADDR_TYPE_DIST:
+		type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
+		addr_ptr = &vgic->vgic_dist_base;
+		alignment = SZ_64K;
+		break;
+	case KVM_VGIC_V3_ADDR_TYPE_REDIST:
+		type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
+		addr_ptr = &vgic->vgic_redist_base;
+		alignment = SZ_64K;
+		break;
+#endif
+	default:
+		r = -ENODEV;
+		goto out;
+	}
+
+	if (vgic->vgic_model != type_needed) {
+		r = -ENODEV;
+		goto out;
+	}
+
+	if (write) {
+		r = vgic_check_ioaddr(kvm, addr_ptr, *addr, alignment);
+		if (!r)
+			*addr_ptr = *addr;
+	} else {
+		*addr = *addr_ptr;
+	}
+
+out:
+	mutex_unlock(&kvm->lock);
+	return r;
+}
+
 static int vgic_set_common_attr(struct kvm_device *dev,
 				struct kvm_device_attr *attr)
 {
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 77b0ab3..6abc9a3 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -19,6 +19,9 @@
 #define PRODUCT_ID_KVM		0x4b	/* ASCII code K */
 #define IMPLEMENTER_ARM		0x43b
 
+#define VGIC_ADDR_UNDEF		(-1)
+#define IS_VGIC_ADDR_UNDEF(_x)  ((_x) == VGIC_ADDR_UNDEF)
+
 #define INTERRUPT_ID_BITS_SPIS	10
 #define VGIC_PRI_BITS		5