On 24/01/2020 13:43, Amit Shah wrote: > On Thu, 2020-01-23 at 16:16 +0100, Laurent Vivier wrote: >> The kernel needs sometime to be able to cancel an ongoing command. >> >> For instance, if the virtio-rng device uses the egd backend >> and this backend doesn't provide data, the buffer provided by the >> kernel is kept as long as it is needed. >> >> On the kernel side, a read blocks until the buffer returns from QEMU. >> >> As the read is done with a mutex held, all the hw_random interface >> hangs and we cannot switch to another hw_random backend. >> >> So this series adds a control queue to the virtio-rng device to allow >> to flush the virtio-rng input queue to release the kernel mutex and >> to allow to switch to another device. >> >> The kernel side series can be found at: >> >> https://github.com/vivier/linux/commits/virtio-rng-ctrl > > Did you submit the kernel series too? Can you please CC me to it?
No, I didn't. I'd like to have some comments on the QEMU side first. QEMU list is generally more responsive than kernel one. It's why I put the link to my linux branch here. > This will need spec changes as well, can you please point me to them > too? The same here. I didn't update the specs, I'd like to have some comments before. BTW, where can I find the specs to update? Is this https://github.com/oasis-tcs/virtio-spec ? > I also recall a previous discussion about this, but my search-fu is > failing to find it... See [RFC] virtio-rng: add a watchdog https://patchwork.kernel.org/patch/10987983/ Thanks, Laurent
