CVE-2022-49146

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

virtio: use virtio_device_ready() in virtio_device_restore()

After waking up a suspended VM, the kernel prints the following trace for virtio drivers which do not directly call virtio_device_ready() in the .restore:

PM: suspend exit
irq 22: nobody cared (try booting with the "irqpoll" option)
Call Trace:
 <IRQ>
 dump_stack_lvl+0x38/0x49
 dump_stack+0x10/0x12
 __report_bad_irq+0x3a/0xaf
 note_interrupt.cold+0xb/0x60
 handle_irq_event+0x71/0x80
 handle_fasteoi_irq+0x95/0x1e0
 __common_interrupt+0x6b/0x110
 common_interrupt+0x63/0xe0
 asm_common_interrupt+0x1e/0x40
 ? __do_softirq+0x75/0x2f3
 irq_exit_rcu+0x93/0xe0
 sysvec_apic_timer_interrupt+0xac/0xd0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20
 arch_cpu_idle+0x12/0x20
 default_idle_call+0x39/0xf0
 do_idle+0x1b5/0x210
 cpu_startup_entry+0x20/0x30
 start_secondary+0xf3/0x100
 secondary_startup_64_no_verify+0xc3/0xcb
 </TASK>
handlers:
[<000000008f9bac49>] vp_interrupt
[<000000008f9bac49>] vp_interrupt
Disabling IRQ #22

This happens because we don't invoke .enable_cbs callback in virtio_device_restore(). That callback is used by some transports (e.g. virtio-pci) to enable interrupts.

Let's fix it, by calling virtio_device_ready() as we do in virtio_dev_probe(). This function calls .enable_cts callback and sets DRIVER_OK status bit.

This fix also avoids setting DRIVER_OK twice for those drivers that call virtio_device_ready() in the .restore.