Re: [Qemu-devel] [RFC PATCH 0/4] virtio-rng and RngBackend infrastructure (v2)
On (Sun) 01 Jul 2012 [23:06:36], Paul Brook wrote: This series depends on my QOM -object series that I just posted. In Amit's thread on virtio-rng, danpb mentioned that we really ought to have a proper RNG backend infrastructure and of course he's correct on that. Now that we have QOM, I wanted to demonstrate how we can use QOM to construct a complete backend without adding any new infrastructure. I've now implemented a urandom and egd backend and tested them. I think the first three patches are ready to go. I never really understood why this exists in the first place. It's a simple readonly charcter device. IMHO you should be using virtio-serial. This is virtio-console v.s. virtio-serial all over again. The only thing close to a reason I've heard is that guest OS is incompetent and can't source random rata from a serial device. Linux has a virtio-rng driver for quite a while; some other hypervisor implementation may have the corresponding device, I'm not aware of it. This series just adds a corresponding device to qemu. You're right that it's just a chardev interface, and virtio-serial would've been ideal for this, but given Linux has a driver already, it's best to add the device to qemu. Even accepting the pointless guest device, I see absolutely no reason to have special infrastructure for this within qemu. Character devices do everything you need. Creating annother read stream of data API is needless duplication and only going to reintroduce bugs we already fixed in the character device layer. Well I do agree with this qemu doesn't really need to bother about the various ways of getting random numbers, just accept them over a chardev and fwd them to the guest. Amit
Re: [Qemu-devel] [RFC PATCH 0/4] virtio-rng and RngBackend infrastructure (v2)
This series depends on my QOM -object series that I just posted. In Amit's thread on virtio-rng, danpb mentioned that we really ought to have a proper RNG backend infrastructure and of course he's correct on that. Now that we have QOM, I wanted to demonstrate how we can use QOM to construct a complete backend without adding any new infrastructure. I've now implemented a urandom and egd backend and tested them. I think the first three patches are ready to go. I never really understood why this exists in the first place. It's a simple readonly charcter device. IMHO you should be using virtio-serial. This is virtio-console v.s. virtio-serial all over again. The only thing close to a reason I've heard is that guest OS is incompetent and can't source random rata from a serial device. Even accepting the pointless guest device, I see absolutely no reason to have special infrastructure for this within qemu. Character devices do everything you need. Creating annother read stream of data API is needless duplication and only going to reintroduce bugs we already fixed in the character device layer. Paul
[Qemu-devel] [RFC PATCH 0/4] virtio-rng and RngBackend infrastructure (v2)
This series depends on my QOM -object series that I just posted. In Amit's thread on virtio-rng, danpb mentioned that we really ought to have a proper RNG backend infrastructure and of course he's correct on that. Now that we have QOM, I wanted to demonstrate how we can use QOM to construct a complete backend without adding any new infrastructure. I've now implemented a urandom and egd backend and tested them. I think the first three patches are ready to go. I have not changed much about patch 4/4. There are some issues with it that I've noticed so I'll respond here and provide the feedback. Patch 4/4 is why I've marked this whole series as RFC as I don't think it's ready to apply yet.
