Re: [PATCH v1 2/2] virtio-mmio: add features for virtio-mmio specification version 3

From: Liu, Jing2
Date: Mon Jan 06 2020 - 02:24:24 EST

On 1/5/2020 6:42 PM, Michael S. Tsirkin wrote:
On Thu, Dec 26, 2019 at 09:16:19PM +0800, Liu, Jiang wrote:
2) The mask and unmask control is missed

but the extension doesnât support 3) because
we noticed that the Linux virtio subsystem doesnât really make use of interrupt masking/unmasking.
Linux uses masking/unmasking in order to migrate interrupts between

Hi Michael,

Thanks for reviewing the patches!

When trying to study the mask/unmask use case during migrating irq, it seems being used e.g.

1) migrate irq(s) away from offline cpu

2) irq affinity is changing, while an interrupt comes so it sets SETAFFINITY_PENDING and

the lapic (e.g. x86) does the mask and unmask to finish the pending during ack.

Is this right? So we should have mask/unmask for each vector.