Hi Vladimir, Currently, mem-to-mem dma transfers happen within a single process address space. This feature aims to extend support for transfers across multiple process address spaces to meet the requirements of inter-process or inter-VM networking. In environments where share memory is not feasible due to security concerns, this feature allows controlled software to use DMA for packet transfers as needed. Regards. From: Medvedkin, Vladimir Sent: Monday, July 14, 2025 3:47 PM To: dev@dpdk.org Cc: Bruce Richardson Subject: [EXTERNAL] Re: [PATCH v0 1/1] doc: announce inter-device DMA capability support in dmadev Hi Vamsi, Could you please tell us more about usecases for this feature? Thanks! On 7/10/2025 9: 51 AM, Vamsi Krishna wrote: > From: Vamsi Attunuru > > Modern DMA hardware supports data transfer between ZjQcmQRYFpfptBannerStart Prioritize security for external emails: Confirm sender and content safety before clicking links or opening attachments Report Suspicious ‌ ZjQcmQRYFpfptBannerEnd Hi Vamsi, Could you please tell us more about usecases for this feature? Thanks! On 7/10/2025 9:51 AM, Vamsi Krishna wrote: > From: Vamsi Attunuru > > > Modern DMA hardware supports data transfer between multiple > DMA devices, enabling data communication across isolated domains or > containers. To facilitate this, the ``dmadev`` library requires changes > to allow devices to register with or unregisters from DMA groups for > inter-device communication. This feature is planned for inclusion > in DPDK 25.11. > > Signed-off-by: Vamsi Attunuru > > --- > doc/guides/rel_notes/deprecation.rst | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst > index e2d4125308..46836244dd 100644 > --- a/doc/guides/rel_notes/deprecation.rst > +++ b/doc/guides/rel_notes/deprecation.rst > @@ -152,3 +152,10 @@ Deprecation Notices > * bus/vmbus: Starting DPDK 25.11, all the vmbus API defined in > ``drivers/bus/vmbus/rte_bus_vmbus.h`` will become internal to DPDK. > Those API functions are used internally by DPDK core and netvsc PMD. > + > +* dmadev: a new capability flag ``RTE_DMA_CAPA_INTER_DEV`` will be added > + to advertise DMA device's inter-device DMA copy capability. To enable > + this functionality, a few dmadev APIs will be added to configure the DMA > + access groups, facilitating coordinated data communication between devices. > + A new ``dev_idx`` field will be added to the ``struct rte_dma_vchan_conf`` > + structure to configure a vchan for data transfers between any two DMA devices. -- Regards, Vladimir