Some dropped quoted text restored. Vincent JARDIN <vincent.jardin at 6wind.com> writes:> Markus, > > see inline (I am not on all mailing list, please, keep the cc list). > >> Sure! The reasons for my dislike range from practical to >> philosophical. >> >> My practical concerns include: >> >> 1. ivshmem code needs work, but has no maintainer > See David's contributions: > http://patchwork.ozlabs.org/patch/358750/We're grateful for David's patch for qemu-char.c, but this isn't ivshmem maintenance, yet.>> - Error handling is generally poor. For instance, "device_add >> ivshmem" kills your guest instantly. >> >> - More subjectively, I don't trust the code to be robust against >> abuse by our own guest, or the other guests sharing the memory. >> Convincing me would take a code audit. >> >> - MAINTAINERS doesn't cover ivshmem.c. >> >> - The last non-trivial commit that isn't obviously part of some >> tree-wide infrastructure or cleanup work is from September 2012 >> (commit c08ba66). >> >> 2. There is no libvirt support > > One can use qemu without libvivrt.You asked me for my reasons for disliking ivshmem. This is one. Sure, I can drink my water through a straw while standing on one foot, but that doesn't mean I have to like it. And me not liking it doesn't mean the next guy shouldn't like it. To each their own.>> 3. Out-of-tree server program required for full functionality >> >> Interrupts require a "shared memory server" running in the host (see >> docs/specs/ivshmem_device_spec.txt). It doesn't tell where to find >> one. The initial commit 6cbf4c8 points to >> <www.gitorious.org/nahanni>. That repository's last commit is from >> September 2012. He's dead, Jim. >> >> ivshmem_device_spec.txt is silent on what the server is supposed to >> do. > > We have the source code, it provides the documentation to write our > own better server program.Good for you. Not good enough for the QEMU community. QEMU features requiring on out-of-tree software to be useful are fine, as long as said out-of-tree software is readily available to QEMU developers and users. Free software with a community around it and packaged in major distros qualifies. If you haven't got that, talk to us to find out whether what you've got qualifies, and if not, what you'd have to do to make it qualify. Back when we accepted ivshmem, the out-of-tree parts it needs were well below the "community & packaged" bar. But folks interested in it talked to us, and the fact that it's in shows that QEMU maintainers decided what they had then was enough. Unfortunately, we now have considerably less: Nahanni appears to be dead. An apparently dead git repository you can study is not enough. The fact that you hold an improved reimplementation privately is immaterial. So is the (plausible) claim that others could also create a reimplementation.>> If this server requires privileges: I don't trust it without an >> audit. >> >> 4. Out-of-tree kernel uio driver required > > No, it is optional.Good to know. Would you be willing to send a patch to ivshmem_device_spec.txt clarifying that?>> The device is "intended to be used with the provided UIO driver" >> (ivshmem_device_spec.txt again). As far as I can tell, the "provided >> UIO driver" is the one in the dead Nahanni repo. >> >> By now, you should be expecting this: I don't trust that one either. >> >> These concerns are all fixable, but it'll take serious work, and time. >> Something like: >> >> * Find a maintainer for the device model > I guess, we can find it into the DPDK.org community. >> * Review and fix its code >> >> * Get the required kernel module upstream > > which module? uio, it is not required. > >> * Get all the required parts outside QEMU packaged in major distros, or >> absorbed into QEMU > > Redhat did disable it. why? it is there in QEMU.Up to now, I've been wearing my QEMU hat. Let me exchange it for my Red one for a bit. We (Red Hat) don't just package & ship metric tons of random free software. We package & ship useful free software we can support for many, many years. Sometimes, we find that we have to focus serious development resources on making something useful supportable (Paolo mentioned qcow2). We obviously can't focus on everything, though. Anyway, ivshmem didn't make the cut for RHEL-7.0. Sorry if that inconveniences you. To get it into RHEL, you need to show it's both useful and supportable. Building a community around it would go a long way towards that. If you want to discuss this in more detail with us, you may want to try communication channels provided by your RHEL subscription in addition to the QEMU development mailing list. Don't be shy, you're paying for it! As always, I'm not speaking for myself, not my employer. Okay, wearing my QEMU hat again.>> In short, create a viable community around ivshmem, either within the >> QEMU community, or separately but cooperating. > > At least, DPDK.org community is a community using it.Using something isn't the same as maintaining something. But it's a necessary first step. [...]
(+merging with Paolo's email because of overlaps)>> see inline (I am not on all mailing list, please, keep the cc list). >>>>> 1. ivshmem code needs work, but has no maintainer >> See David's contributions: >> http://patchwork.ozlabs.org/patch/358750/ > > We're grateful for David's patch for qemu-char.c, but this isn't ivshmem > maintenance, yet.others can come (doc), see below.>>> 2. There is no libvirt support >> >> One can use qemu without libvivrt. > > You asked me for my reasons for disliking ivshmem. This is one. > > Sure, I can drink my water through a straw while standing on one foot, > but that doesn't mean I have to like it. And me not liking it doesn't > mean the next guy shouldn't like it. To each their own.I like using qemu without libvirt, libvirt is not part of qemu. Let's avoid trolling about it ;)> Back when we accepted ivshmem, the out-of-tree parts it needs were well > below the "community & packaged" bar. But folks interested in it talked > to us, and the fact that it's in shows that QEMU maintainers decided > what they had then was enough. > > Unfortunately, we now have considerably less: Nahanni appears to be > dead.agree and to bad it is dead. We should let Nahanni dead since ivshmem is a QEMU topic now, see below. Does it make sense?> > An apparently dead git repository you can study is not enough. The fact > that you hold an improved reimplementation privately is immaterial. So > is the (plausible) claim that others could also create a > reimplementation.Got the point. What's about a patch to docs/specs/ivshmem_device_spec.txt that improves it? I can make qemu's ivshmem better: - keep explaining memnic for instance, - explain how to write other ivshmem. does it help?>>> 4. Out-of-tree kernel uio driver required >> >> No, it is optional. > > Good to know. Would you be willing to send a patch to > ivshmem_device_spec.txt clarifying that?got the point, yes,>>> * Get all the required parts outside QEMU packaged in major distros, or >>> absorbed into QEMU >> >> Redhat did disable it. why? it is there in QEMU. > > Up to now, I've been wearing my QEMU hat. Let me exchange it for my Red > one for a bit. > > We (Red Hat) don't just package & ship metric tons of random free > software. We package & ship useful free software we can support for > many, many years. > > Sometimes, we find that we have to focus serious development resources > on making something useful supportable (Paolo mentioned qcow2). We > obviously can't focus on everything, though.Good open technology should rule. ivshmem has use cases. And I go agree with you, it is like the phoenix, it has to be re-explained/documented to be back to life. I was not aware that the QEMU community was missing ivshmem contributors (my bad I did not check MAINTAINERS).> Anyway, ivshmem didn't make the cut for RHEL-7.0. Sorry if that > inconveniences you. To get it into RHEL, you need to show it's both > useful and supportable. Building a community around it would go a long > way towards that.understood.> If you want to discuss this in more detail with us, you may want to try > communication channels provided by your RHEL subscription in addition to > the QEMU development mailing list. Don't be shy, you're paying for it!done. I was focusing on DPDK.org and ignorant of QEMU's status, thinking Redhat was covering it. How to know which part of an opensource software are and are not included into Redhat. Sales are ignorant about it ;). Redhat randomly disables some files at compilation (for some good reasons I guess, but not public rationals or I am missing something). Feel free to open this PR to anyone: https://bugzilla.redhat.com/show_bug.cgi?id=1088332>>> In short, create a viable community around ivshmem, either within the >>> QEMU community, or separately but cooperating. >> >> At least, DPDK.org community is a community using it. > > Using something isn't the same as maintaining something. But it's a > necessary first step.understood, after David's patch, documentation will come. (now Paolo's email since there were some overlaps) > Markus especially referred to parts *outside* QEMU: the server, the > uio driver, etc. These out-of-tree, non-packaged parts of ivshmem > are one of the reasons why Red Hat has disabled ivshmem in RHEL7. You made the right choices, these out-of-tree packages are not required. You can use QEMU's ivshmem without any of the out-of-tree packages. The out-of-tree packages are just some examples of using ivshmem. > He also listed many others. Basically for parts of QEMU that are not > of high quality, we either fix them (this is for example what we did > for qcow2) or disable them. Not just ivshmem suffered this fate, for > example many network cards, sound cards, SCSI storage adapters. I and David (cc) are working on making it better based on the issues that are found. > Now, vhost-user is in the process of being merged for 2.1. Compared to the DPDK solution: now, you cannot compare vhost-user to DPDK/ivshmem; both should exsit because they have different scope and use cases. It is like comparing two different(A) models of IPC: - vhost-user -> networking use case specific - ivshmem -> framework to be generic to have shared memory for many use cases (HPC, in-memory-database, a network too like memnic). Later one, some news services will be needed for shared memory. virtio will come in picture (see VIRTIO_F_RING_SHMEM_ADDR's threads). Currently, ivhsmem is the only "stable" option since there remains many unsolved issues with virtio and shared memory. > * it doesn't require hugetlbfs (which only enabled shared memory by > chance in older QEMU releases, that was never documented) ivhsmem does not require hugetlbfs. It is optional. > * it doesn't require ivshmem (it does require shared memory, which > will also be added to 2.1) somehow I agree: we need both models: vhost-user and ivshmem because of the previous (A) comments. > * it doesn't require the kernel driver from the DPDK sample ivhsmem does not require DPDK kernel driver. see memnic's PMD: http://dpdk.org/browse/memnic/tree/pmd/pmd_memnic.c > * it is not just shared memory, but also defines an interface to use > it (another of Markus's points) agreed Paolo: but you short narrow it for networking use cases only. Shared memory ? la ivshmem provides other features (see (A) again). > > vhost-user is superior, and it is superior because it has been > designed > from the get-go through cooperation of all interested parties (namely > QEMU and snabbswitch). It is not an argument. vhost-user is a specific case. Best regards, Vincent
Nahanni's poor current development coupled with virtIO's promising expansion was what encouraged us to explore virtIO-serial [1] for inter-virtual machine communication. Though virtIO-serial as it is isn't helpful for inter-VM communication, some work is needed for this purpose and this is exactly what we (I and two of my fellow classmates) accomplished. We haven't published it yet since we do need to polish yet for upstreaming it and are planning do it in near future. [1]: http://fedoraproject.org/wiki/Features/VirtioSerial On Fri, Jun 13, 2014 at 2:16 PM, Markus Armbruster <armbru at redhat.com> wrote:> Some dropped quoted text restored. > > Vincent JARDIN <vincent.jardin at 6wind.com> writes: > > > Markus, > > > > see inline (I am not on all mailing list, please, keep the cc list). > > > >> Sure! The reasons for my dislike range from practical to > >> philosophical. > >> > >> My practical concerns include: > >> > >> 1. ivshmem code needs work, but has no maintainer > > See David's contributions: > > http://patchwork.ozlabs.org/patch/358750/ > > We're grateful for David's patch for qemu-char.c, but this isn't ivshmem > maintenance, yet. > > >> - Error handling is generally poor. For instance, "device_add > >> ivshmem" kills your guest instantly. > >> > >> - More subjectively, I don't trust the code to be robust against > >> abuse by our own guest, or the other guests sharing the memory. > >> Convincing me would take a code audit. > >> > >> - MAINTAINERS doesn't cover ivshmem.c. > >> > >> - The last non-trivial commit that isn't obviously part of some > >> tree-wide infrastructure or cleanup work is from September 2012 > >> (commit c08ba66). > >> > >> 2. There is no libvirt support > > > > One can use qemu without libvivrt. > > You asked me for my reasons for disliking ivshmem. This is one. > > Sure, I can drink my water through a straw while standing on one foot, > but that doesn't mean I have to like it. And me not liking it doesn't > mean the next guy shouldn't like it. To each their own. > > >> 3. Out-of-tree server program required for full functionality > >> > >> Interrupts require a "shared memory server" running in the host (see > >> docs/specs/ivshmem_device_spec.txt). It doesn't tell where to find > >> one. The initial commit 6cbf4c8 points to > >> <www.gitorious.org/nahanni>. That repository's last commit is from > >> September 2012. He's dead, Jim. > >> > >> ivshmem_device_spec.txt is silent on what the server is supposed to > >> do. > > > > We have the source code, it provides the documentation to write our > > own better server program. > > Good for you. Not good enough for the QEMU community. > > QEMU features requiring on out-of-tree software to be useful are fine, > as long as said out-of-tree software is readily available to QEMU > developers and users. > > Free software with a community around it and packaged in major distros > qualifies. If you haven't got that, talk to us to find out whether what > you've got qualifies, and if not, what you'd have to do to make it > qualify. > > Back when we accepted ivshmem, the out-of-tree parts it needs were well > below the "community & packaged" bar. But folks interested in it talked > to us, and the fact that it's in shows that QEMU maintainers decided > what they had then was enough. > > Unfortunately, we now have considerably less: Nahanni appears to be > dead. > > An apparently dead git repository you can study is not enough. The fact > that you hold an improved reimplementation privately is immaterial. So > is the (plausible) claim that others could also create a > reimplementation. > > >> If this server requires privileges: I don't trust it without an > >> audit. > >> > >> 4. Out-of-tree kernel uio driver required > > > > No, it is optional. > > Good to know. Would you be willing to send a patch to > ivshmem_device_spec.txt clarifying that? > > >> The device is "intended to be used with the provided UIO driver" > >> (ivshmem_device_spec.txt again). As far as I can tell, the "provided > >> UIO driver" is the one in the dead Nahanni repo. > >> > >> By now, you should be expecting this: I don't trust that one either. > >> > >> These concerns are all fixable, but it'll take serious work, and time. > >> Something like: > >> > >> * Find a maintainer for the device model > > I guess, we can find it into the DPDK.org community. > >> * Review and fix its code > >> > >> * Get the required kernel module upstream > > > > which module? uio, it is not required. > > > >> * Get all the required parts outside QEMU packaged in major distros, or > >> absorbed into QEMU > > > > Redhat did disable it. why? it is there in QEMU. > > Up to now, I've been wearing my QEMU hat. Let me exchange it for my Red > one for a bit. > > We (Red Hat) don't just package & ship metric tons of random free > software. We package & ship useful free software we can support for > many, many years. > > Sometimes, we find that we have to focus serious development resources > on making something useful supportable (Paolo mentioned qcow2). We > obviously can't focus on everything, though. > > Anyway, ivshmem didn't make the cut for RHEL-7.0. Sorry if that > inconveniences you. To get it into RHEL, you need to show it's both > useful and supportable. Building a community around it would go a long > way towards that. > > If you want to discuss this in more detail with us, you may want to try > communication channels provided by your RHEL subscription in addition to > the QEMU development mailing list. Don't be shy, you're paying for it! > > As always, I'm not speaking for myself, not my employer. > > Okay, wearing my QEMU hat again. > > >> In short, create a viable community around ivshmem, either within the > >> QEMU community, or separately but cooperating. > > > > At least, DPDK.org community is a community using it. > > Using something isn't the same as maintaining something. But it's a > necessary first step. > > [...] > >-- Thanks and regards, Jobin Raju George Final Year, Information Technology College of Engineering Pune Alternate e-mail: georgejr10.it at coep.ac.in -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20140613/d76c8217/attachment-0001.html>
Nahanni's poor current development coupled with virtIO's promising expansion was what encouraged us to explore virtIO-serial [1] for inter-virtual machine communication. Though virtIO-serial as it is isn't helpful for inter-VM communication, some work is needed for this purpose and this is exactly what we (I and two of my fellow classmates) accomplished. We haven't published it yet since we do need to polish yet for upstreaming it and are planning do it in near future. [1]: http://fedoraproject.org/wiki/Features/VirtioSerial On Fri, Jun 13, 2014 at 2:56 PM, Vincent JARDIN <vincent.jardin at 6wind.com> wrote:> > (+merging with Paolo's email because of overlaps) > > >>> see inline (I am not on all mailing list, please, keep the cc list). >>> > >>>> 1. ivshmem code needs work, but has no maintainer >>> >>> See David's contributions: >>> http://patchwork.ozlabs.org/patch/358750/ >> >> >> We're grateful for David's patch for qemu-char.c, but this isn't ivshmem >> maintenance, yet. > > > others can come (doc), see below. > > >>>> 2. There is no libvirt support >>> >>> >>> One can use qemu without libvivrt. >> >> >> You asked me for my reasons for disliking ivshmem. This is one. >> >> Sure, I can drink my water through a straw while standing on one foot, >> but that doesn't mean I have to like it. And me not liking it doesn't >> mean the next guy shouldn't like it. To each their own. > > > I like using qemu without libvirt, libvirt is not part of qemu. > Let's avoid trolling about it ;) > > >> Back when we accepted ivshmem, the out-of-tree parts it needs were well >> below the "community & packaged" bar. But folks interested in it talked >> to us, and the fact that it's in shows that QEMU maintainers decided >> what they had then was enough. >> >> Unfortunately, we now have considerably less: Nahanni appears to be >> dead. > > > agree and to bad it is dead. We should let Nahanni dead since ivshmem is a QEMU topic now, see below. Does it make sense? > > >> >> An apparently dead git repository you can study is not enough. The fact >> that you hold an improved reimplementation privately is immaterial. So >> is the (plausible) claim that others could also create a >> reimplementation. > > > Got the point. What's about a patch to docs/specs/ivshmem_device_spec.txt that improves it? > > I can make qemu's ivshmem better: > - keep explaining memnic for instance, > - explain how to write other ivshmem. > > does it help? > > >>>> 4. Out-of-tree kernel uio driver required >>> >>> >>> No, it is optional. >> >> >> Good to know. Would you be willing to send a patch to >> ivshmem_device_spec.txt clarifying that? > > > got the point, yes, > > >>>> * Get all the required parts outside QEMU packaged in major distros, or >>>> absorbed into QEMU >>> >>> >>> Redhat did disable it. why? it is there in QEMU. >> >> >> Up to now, I've been wearing my QEMU hat. Let me exchange it for my Red >> one for a bit. >> >> We (Red Hat) don't just package & ship metric tons of random free >> software. We package & ship useful free software we can support for >> many, many years. >> >> Sometimes, we find that we have to focus serious development resources >> on making something useful supportable (Paolo mentioned qcow2). We >> obviously can't focus on everything, though. > > > Good open technology should rule. ivshmem has use cases. And I go agree with you, it is like the phoenix, it has to be re-explained/documented to be back to life. I was not aware that the QEMU community was missing ivshmem contributors (my bad I did not check MAINTAINERS). > > >> Anyway, ivshmem didn't make the cut for RHEL-7.0. Sorry if that >> inconveniences you. To get it into RHEL, you need to show it's both >> useful and supportable. Building a community around it would go a long >> way towards that. > > > understood. > > >> If you want to discuss this in more detail with us, you may want to try >> communication channels provided by your RHEL subscription in addition to >> the QEMU development mailing list. Don't be shy, you're paying for it! > > > done. I was focusing on DPDK.org and ignorant of QEMU's status, thinking Redhat was covering it. How to know which part of an opensource software are and are not included into Redhat. Sales are ignorant about it ;). Redhat randomly disables some files at compilation (for some good reasons I guess, but not public rationals or I am missing something). > > Feel free to open this PR to anyone: > https://bugzilla.redhat.com/show_bug.cgi?id=1088332 > > >>>> In short, create a viable community around ivshmem, either within the >>>> QEMU community, or separately but cooperating. >>> >>> >>> At least, DPDK.org community is a community using it. >> >> >> Using something isn't the same as maintaining something. But it's a >> necessary first step. > > > understood, after David's patch, documentation will come. > > (now Paolo's email since there were some overlaps) > > > Markus especially referred to parts *outside* QEMU: the server, the > > uio driver, etc. These out-of-tree, non-packaged parts of ivshmem > > are one of the reasons why Red Hat has disabled ivshmem in RHEL7. > > You made the right choices, these out-of-tree packages are not required. You can use QEMU's ivshmem without any of the out-of-tree packages. The out-of-tree packages are just some examples of using ivshmem. > > > He also listed many others. Basically for parts of QEMU that are not > > of high quality, we either fix them (this is for example what we did > > for qcow2) or disable them. Not just ivshmem suffered this fate, for > > example many network cards, sound cards, SCSI storage adapters. > > I and David (cc) are working on making it better based on the issues that are found. > > > Now, vhost-user is in the process of being merged for 2.1. Compared to the DPDK solution: > > now, you cannot compare vhost-user to DPDK/ivshmem; both should exsit because they have different scope and use cases. It is like comparing two different(A) models of IPC: > - vhost-user -> networking use case specific > - ivshmem -> framework to be generic to have shared memory for many use cases (HPC, in-memory-database, a network too like memnic). > > Later one, some news services will be needed for shared memory. virtio will come in picture (see VIRTIO_F_RING_SHMEM_ADDR's threads). Currently, ivhsmem is the only "stable" option since there remains many unsolved issues with virtio and shared memory. > > > * it doesn't require hugetlbfs (which only enabled shared memory by > > chance in older QEMU releases, that was never documented) > > ivhsmem does not require hugetlbfs. It is optional. > > > * it doesn't require ivshmem (it does require shared memory, which > > will also be added to 2.1) > > somehow I agree: we need both models: vhost-user and ivshmem because of the previous (A) comments. > > > * it doesn't require the kernel driver from the DPDK sample > > ivhsmem does not require DPDK kernel driver. see memnic's PMD: > http://dpdk.org/browse/memnic/tree/pmd/pmd_memnic.c > > > * it is not just shared memory, but also defines an interface to use > > it (another of Markus's points) > > agreed Paolo: but you short narrow it for networking use cases only. Shared memory ? la ivshmem provides other features (see (A) again). > > > > > vhost-user is superior, and it is superior because it has been > > designed > > from the get-go through cooperation of all interested parties (namely > > QEMU and snabbswitch). > > It is not an argument. vhost-user is a specific case. > > Best regards, > Vincent >
Hello, On 06/13/2014 11:26 AM, Vincent JARDIN wrote:> ivhsmem does not require hugetlbfs. It is optional. > > > * it doesn't require ivshmem (it does require shared memory, which > > will also be added to 2.1)Right, hugetlbfs is not required. A posix shared memory or tmpfs can be used instead. For instance, to use /dev/shm/foobar: qemu-system-x86_64 -enable-kvm -cpu host [...] \ -device ivshmem,size=16,shm=foobar Regards, Olivier
Il 13/06/2014 11:26, Vincent JARDIN ha scritto:>> Markus especially referred to parts *outside* QEMU: the server, the >> uio driver, etc. These out-of-tree, non-packaged parts of ivshmem >> are one of the reasons why Red Hat has disabled ivshmem in RHEL7. > > You made the right choices, these out-of-tree packages are not required. > You can use QEMU's ivshmem without any of the out-of-tree packages. The > out-of-tree packages are just some examples of using ivshmem.Fine, however Red Hat would also need a way to test ivshmem code, with proper quality assurance (that also benefits upstream, of course). With ivshmem this is not possible without the out-of-tree packages. Disabling all the unwanted devices is a lot of work and thankless too (you only get complaints, in fact!). But we prefer to ship only what we know we can test, support and improve. We do not want customers' bug reports to languish because they are using code that cannot really be fixed. Note that we do take into account community contributions in choosing which new code can be supported. For example most work on VMDK images was done by Fam when he was a student, libiscsi is mostly the work of Peter Lieven, and so on; both of them are supported in RHEL. These people did/do a great job, and we were happy to embrace those features! Now, putting back my QEMU hat...>> He also listed many others. Basically for parts of QEMU that are not >> of high quality, we either fix them (this is for example what we did >> for qcow2) or disable them. Not just ivshmem suffered this fate, for >> example many network cards, sound cards, SCSI storage adapters. > > I and David (cc) are working on making it better based on the issues > that are found. > >> Now, vhost-user is in the process of being merged for 2.1. Compared > to the DPDK solution: > > now, you cannot compare vhost-user to DPDK/ivshmem; both should exsit > because they have different scope and use cases. It is like comparing > two different(A) models of IPC: > - vhost-user -> networking use case specificNot necessarily. First and foremost, vhost-user defines an API for communication between QEMU and the host, including: * file descriptor passing for the shared memory file * mapping offsets in shared memory to physical memory addresses in the guests * passing dirty memory information back and forth, so that migration is not prevented * sending interrupts to a device * setting up ring buffers in the shared memory None of these is virtio specific, except the last (even then, you could repurpose the messages to pass the address of the whole shared memory area, instead of the vrings only). Yes, the only front-end for vhost-user, right now, is a network device. But it is possible to connect vhost-scsi to vhost-user as well, it is possible to develop a vhost-serial as well, and it is possible to only use the RPC and develop arbitrary shared-memory based tools using this API. It's just that no one has done it yet. Also, vhost-user is documented! See here: https://lists.gnu.org/archive/html/qemu-devel/2014-03/msg00581.html The only part of ivshmem that vhost doesn't include is the n-way inter-guest doorbell. This is the part that requires a server and uio driver. vhost only supports host->guest and guest->host doorbells.>> * it doesn't require hugetlbfs (which only enabled shared memory by >> chance in older QEMU releases, that was never documented) > > ivhsmem does not require hugetlbfs. It is optional. > >> * it doesn't require the kernel driver from the DPDK sample > > ivhsmem does not require DPDK kernel driver. see memnic's PMD: > http://dpdk.org/browse/memnic/tree/pmd/pmd_memnic.cYou're right, I was confusing memnic and the vhost example in DPDK. Paolo