On 10.06.21 11:51, Stefano Gurrieri wrote: > Hi Jan, > > so if I wanted to start a second Linux inmate cell and mount a rootFS > installed on the second partition of my eMMC (/dev/mmcblk2p2) is it > feasible or not? It's not still much clear...sorry. > What do you mean /"In that case, you need one cell taking ownership of > the controller, *serving other cells as proxy*."/? >
Jailhouse itself does not virtualize common devices (like storage controllers) as full-featured hypervisors do. Thus, you need to put the hardware driver for a particular device into one cell (e.g. using Linux, but could be other OS-stacks as well) and have a service there that exposes said /dev/mmcblk2p2 as virtual block device to another cell (trivial example is [1]). Obviously, this creates a certain dependency of the cell using this service on that "driver" cell providing it. Jan [1] http://git.kiszka.org/?p=linux.git;a=blob;f=tools/virtio/virtio-ivshmem-block.c;h=c97aa5076a6d22ccd01862f3e4db0e12641825c3;hb=refs/heads/queues/jailhouse > Kind Regards. > Stefano > > Il giorno gio 10 giu 2021 alle ore 10:53 Jan Kiszka > <[email protected] <mailto:[email protected]>> ha scritto: > > 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] > <mailto:jailhouse-dev%[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 > > <https://groups.google.com/d/msgid/jailhouse-dev/0d8757b9-c2f7-266f-8ded-709c632f955d%40siemens.com>. > -- 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/ed4dfa8b-8580-b6d5-e7d0-60e68d602873%40siemens.com.
