[Qemu-devel] Fwd: Qemu Shared memory
Dear developers, I want to design a shared memory for Vm in qemu. So, I also need to design a mechanism to let two vms communicate. Is there already some module in Qemu ? I saw that qemu could support live migration. Can the vm also access the previous machine after migration? Thanks. - Gary
[Qemu-devel] Qemu only uses a Qemu File to communicate in two hosts?
Hi, Does Qemu only use the QEMUFile to load the state of VM after migration? Is there a way for two vm guests to communicate like two threads or processes? Gary
[Qemu-devel] Qemu Shared memory
Dear developers, I want to design a shared memory for Vm in qemu. So, I also need to design a mechanism to let two vms communicate. Is there already some module in Qemu ? I saw that qemu could support live migration. Can the vm also access the previous machine after migration? Thanks. Gary
Re: [Qemu-devel] Qemu only uses a Qemu File to communicate in two hosts?
Hi Eric, Could I find a way for two guests in two hosts to communicate? Like qemu starts one vm in Host 1 and qemu also starts a vm in Host 2, the vm can share their memory. Is there some existed way to do that, like remote IPC in qemu? Thanks for your reply. ---Gary 2014-06-30 17:08 GMT-04:00 Eric Blake : > On 06/30/2014 03:02 PM, Gary Jordan wrote: > > Hi, > > Does Qemu only use the QEMUFile to load the state of VM after migration? > > Normally, yes. Migration must work as a one-way protocol in the common > case when used with default options. > > There is a migration mode that uses RDMA which requires bi-directional > communication in order to speed up aspects of memory migration. But > this mode is transparent to the guest, and requires you to take extra > steps at both source and destination (along with having an infiniband > connection capable of RDMA communication between the two hosts). > > > Is there a way for two vm guests to communicate like two threads or > > processes? > > If there is, it has nothing to do with migration. It sounds like you > are asking about ivshmem and/or virtio; if so, search the archives for > recent discussions on the topic. > > -- > Eric Blake eblake redhat com+1-919-301-3266 > Libvirt virtualization library http://libvirt.org > >
[Qemu-devel] VM id
Does Qemu have a VM id allocated for each VM? I did not find this Id in qemu. HOW deos qemu identify each VM, using thread Id or some other identifiers?
Re: [Qemu-devel] VM id
If I open two session in a migration operation, how does the qemu know which one should be accepted? I saw there was a ram_list to check, but no id of the guest. 2014-07-02 17:59 GMT-04:00 Eric Blake : > On 07/02/2014 01:20 PM, Gary Jordan wrote: > > Does Qemu have a VM id allocated for each VM? I did not find this Id in > > qemu. HOW deos qemu identify each VM, using thread Id or some other > > identifiers? > > Each qemu process manages exactly one VM, so qemu doesn't care what id a > guest has. Higher-level management software, such as libvirt, has > notions of a VM name and UUID (both of which can be specified on the > command line parameters given to qemu, and the UUID can even be > propagated to the guest, such as by SMBIOS readable by dmidecode in the > guest), as well as a VM id (in libvirt's case, a sequentially increasing > number for each VM that libvirt spawns a qemu process for). But that's > getting outside the realm of qemu, since qemu doesn't care what name or > uuid you picked, only whether you have access to the monitor of the qemu > process. > > -- > Eric Blake eblake redhat com+1-919-301-3266 > Libvirt virtualization library http://libvirt.org > >
