Re: [PATCH RFC v2 07/16] vfio-user: get device info

[John Johnson]

> On Aug 24, 2021, at 9:04 AM, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> 
> On Mon, Aug 16, 2021 at 09:42:40AM -0700, Elena Ufimtseva wrote:
>> +int vfio_user_get_info(VFIODevice *vbasedev)
>> +{
>> +    VFIOUserDeviceInfo msg;
>> +
>> +    memset(&msg, 0, sizeof(msg));
>> +    vfio_user_request_msg(&msg.hdr, VFIO_USER_DEVICE_GET_INFO, sizeof(msg), 
>> 0);
>> +    msg.argsz = sizeof(struct vfio_device_info);
>> +
>> +    vfio_user_send_recv(vbasedev->proxy, &msg.hdr, NULL, 0, 0);
>> +    if (msg.hdr.flags & VFIO_USER_ERROR) {
>> +        return -msg.hdr.error_reply;
>> +    }
>> +
>> +    vbasedev->num_irqs = msg.num_irqs;
>> +    vbasedev->num_regions = msg.num_regions;
>> +    vbasedev->flags = msg.flags;
>> +    vbasedev->reset_works = !!(msg.flags & VFIO_DEVICE_FLAGS_RESET);
> 
> No input validation. I haven't checked what happens when num_irqs,
> num_regions, or flags are bogus but it's a little concerning. Unlike
> kernel VFIO, we do not trust these values.
> 

        As in the last reply, vfio-user doesn’t know valid values
from invalid, so I need to re-work this so the PCI-specific code that
calls vfio-user_get_info() can test for invalid values.

                                                        JJ