In the Linux kernel, the following vulnerability has been resolved: irqchip/gic-v4: Don't advertise VLPIs if no ITS is probed When acciden

In the Linux kernel, the following vulnerability has been resolved:

irqchip/gic-v4: Don't advertise VLPIs if no ITS is probed

When accidentally setting “kvm-arm.vgic_v4_enable=1” on a system that has
no MSI controller device tree node and GICv4, it results a panic as
“gic_domain” is NULL and the kernel attempts to access it.

 1Unable to handle kernel NULL pointer dereference at virtual address 0000000000000028
 2Mem abort info:
 3  ESR = 0x0000000096000006
 4 
 5CPU: 1 UID: 0 PID: 295 Comm: lkvm-static Not tainted 7.1.0-rc4-ge3f15ad3970e #5 PREEMPT
 6Hardware name: linux,dummy-virt (DT)
 7pstate: 81402005 (Nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
 8pc : __irq_domain_instantiate+0x1d4/0x578
 9lr : __irq_domain_instantiate+0x1cc/0x578

Set vLPI support to false at init time if the host has no ITS, so it
propagates properly to kvm_vgic_global_state.has_gicv4.