Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [PATCH 6/9] virtio_pci: harden MSI-X interrupts | Date | Mon, 13 Sep 2021 21:38:30 +0200 |
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On Mon, Sep 13 2021 at 15:07, Jason Wang wrote: > On Mon, Sep 13, 2021 at 2:50 PM Michael S. Tsirkin <mst@redhat.com> wrote: >> > But doen't "irq is disabled" basically mean "we told the hypervisor >> > to disable the irq"? What extractly prevents hypervisor from >> > sending the irq even if guest thinks it disabled it? >> >> More generally, can't we for example blow away the >> indir_desc array that we use to keep the ctx pointers? >> Won't that be enough? > > I'm not sure how it is related to the indirect descriptor but an > example is that all the current driver will assume: > > 1) the interrupt won't be raised before virtio_device_ready() > 2) the interrupt won't be raised after reset()
If that assumption exists, then you better keep the interrupt line disabled until virtio_device_ready() has completed and disable it again before reset() is invoked. That's a question of general robustness and not really a question of trusted hypervisors and encrypted guests.
>> > > > > > > +void vp_disable_vectors(struct virtio_device *vdev) >> > > > > > > { >> > > > > > > struct virtio_pci_device *vp_dev = to_vp_device(vdev); >> > > > > > > int i; >> > > > > > > @@ -34,7 +34,20 @@ void vp_synchronize_vectors(struct virtio_device *vdev) >> > > > > > > synchronize_irq(vp_dev->pci_dev->irq);
Don't you want the same change for non-MSI interrupts?
Thanks,
tglx
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