On 10.06.21 09:47, laurent gauty wrote: > Hi, > > I'm currently playing with a NXP dev board based on iMX8Mplus. I'm very > interested by the approach you have developed in the jailhouse project > in order to segregate different cells running different systems. > But as i tried to install jailhouse and played with cells, i reached a > point where i don't understand how jailhouse in intend to behave on > persistent memory (i.e. eMMC / SD). > > The current configuration is to have several cells using the same SD > card / eMMC, but relying on different partitions. And i think that most > of the projects in embedded world will have to deal with only one memory > device (SD, eMMC) for cost and space reasons. > > So here is my question: > is there a way in jailhouse to isolate the persistent memory (for > example partition) of each cells from each others ? > If not existing today, do you plan for this kind of features in the future ? >
The general issue with partitioning of storage is the partitioning of the device access methods to it. With something like AHCI, NVMe or MMC, you have to go through a central point, the controller, in order to talk to different partitions of the same medium. In that case, you need one cell taking ownership of the controller, serving other cells as proxy. That would be the Jailhouse model of it: no device driver in the hypervisor, rather using a cell as driver. To provide virtual access on the physical storage, something like virtio-over-shmem + virtio-block could be a pattern (though not yet production-grade). Or storage over (virtual) network. An alternative to the proxy cell could be if you have a directly memory-mappable storage that does not require coordinated access on a central controller. Or if you had something like SR-IOV capable storage controllers that could present themselves as multiple, thus hardware-partitionable, devices to the host. None of both we've seen or tried so far. HTH, Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux -- You received this message because you are subscribed to the Google Groups "Jailhouse" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jailhouse-dev/0d8757b9-c2f7-266f-8ded-709c632f955d%40siemens.com.
