sys/linux/tests: add a seed that unrolls syz_kvm_vgic_v3_setup()

Provide a test case that replaces syz_kvm_vgic_v3_setup() with a sequence
of 5 KVM ioctls.

Author: ramosian-glider

sys/linux/test/arm64-syz_kvm_setup_syzos_vm-vgicv3-unroll

@@ -0,0 +1,23 @@
+#
+# requires: arch=arm64 -threaded
+#
+r0 = openat$kvm(0, &AUTO='/dev/kvm\x00', 0x0, 0x0)
+r1 = ioctl$KVM_CREATE_VM(r0, AUTO, 0x0)
+r2 = syz_kvm_setup_syzos_vm(r1, &(0x7f0000c00000/0x400000)=nil)
+r3 = syz_kvm_add_vcpu(r2, &AUTO={0x0, &AUTO=[@irq_setup={AUTO, AUTO, {0x1, 0x20}}], AUTO}, 0x0, 0x0)
+#
+# Implementing syz_kvm_vgic_v3_setup(r1, 0x1, 0x100) using raw ioctls:
+#
+ioctl$KVM_CREATE_DEVICE(r1, AUTO, &AUTO={0x7, <r4=>0xffffffffffffffff, 0x0})
+ioctl$KVM_SET_DEVICE_ATTR(r4, AUTO, &AUTO=@attr_arm64={0x0, 0x3, 0x0, &AUTO=0x100})
+ioctl$KVM_SET_DEVICE_ATTR(r4, AUTO, &AUTO=@attr_arm64={0x0, 0x0, 0x2, &AUTO=0x08000000})
+ioctl$KVM_SET_DEVICE_ATTR(r4, AUTO, &AUTO=@attr_arm64={0x0, 0x0, 0x5, &AUTO=0x400000080a0000})
+ioctl$KVM_SET_DEVICE_ATTR(r4, AUTO, &AUTO=@attr_arm64={0x0, 0x4, 0x0, 0x0})
+
+ioctl$KVM_RUN(r3, AUTO, 0x0)
+#
+# Calling KVM_RUN here again would result in infinite loop.
+# Instead, signal SPI 32 (0x1000020), so that the guest can execute another uexit in the IRQ handler.
+#
+ioctl$KVM_IRQ_LINE(r1, AUTO, &AUTO={0x1000020, 0x1})
+ioctl$KVM_RUN(r3, AUTO, 0x0)