On Thu, Jun 08, 2017 at 01:38:12PM +0200, Jan Blunck wrote: > On Wed, Jun 7, 2017 at 9:55 PM, Gaëtan Rivet <gaetan.ri...@6wind.com> wrote: > > On Wed, Jun 07, 2017 at 07:22:05PM +0200, Jan Blunck wrote: > >> On Wed, May 24, 2017 at 5:12 PM, Gaetan Rivet <gaetan.ri...@6wind.com> > >> wrote: > >> > Following the evolutions announced in [1], here is the first part of > >> > the rte_devargs rework planned for 17.08. The rationale has been > >> > partially > >> > explained in [2]. > >> > > >> > This first part covers the introduction of the necessary facilities in > >> > rte_bus to allow for generic device parsing. This API is implemented for > >> > the virtual and PCI buses. Additionally, this rte_bus evolution is being > >> > used within rte_devargs to characterize a device type by its bus. > >> > This work is the first of two parts to reduce the dependency of the EAL > >> > upon specific bus implementations. > >> > > >> > Two public functions are added to rte_bus to help bus recognition: > >> > > >> > - rte_bus_from_name > >> > - rte_bus_from_dev > >> > > >> > These functions are made public because the bus handle within devargs > >> > becomes the generic device type. Recognizing device types is useful for > >> > buses and PMDs alike. > >> > The modified rte_devargs parsing allows declaring on the EAL command line > >> > explicit buses to handle a device. The format is as follow: > >> > > >> > --vdev="virtual:net_ring0" --vdev="net_tap0,iface=tap0" > >> > -w PCI:00:02.0 -w 00:03.0 > >> > > >> > >> I don't see the point of doing this. The --vdev parameter implicitly > >> defines the bus by its name (--vdev aka virtual device). > >> > >> Why don't you add a commandline "--dev" parameter that supports a > >> "bus=" devarg? You would need to clarify what that means for other > >> busses than the virtual one. Is the bus switched into whitelist mode > >> by that? > >> > >> > > > > We cannot keep the current -w, -b and --vdev parameter. Those are > > processed by the EAL, and use specifics from the virtual and PCI buses. > > > > The rte_devargs rework has been to make the same functionality generic > > to all rte_bus. As seen quickly in [2], rte_devargs has two functions: > > > > * Validating a device declaration > > * Keeping the relevant device info until it has been processed. > > > > I don't agree with the validation step. This is highly > device/driver/bus specific and I don't believe that just because you > have created a rte_devargs it is a guarantee that the device is valid.
It is the current API. If an rte_devargs is added to the global list, then it means that the embedded information has been validated. I kept the same behavior but made it generic in the new version. > Besides that it makes statically embedding rte_devargs into other > structures impossible. Why? In the failsafe PMD, I statically embed an rte_devargs to avoid having to insert one in the global device list to remove it afterward. What limitation to this do you see? I think I misunderstand what you mean. > As I see it rte_devargs is a key-value list > with some keys that are generic. This would make application > development much easier. > > The previously encoded information was: - Scan policy / bus (in the type field) - Device designation (PCI location / virtual driver) - kvargs Beside the kvargs, none were generic, so I made them so. I divided the type field into two separate elements as it was conflating two concepts. I do not understand how much simpler we can make this. The fields have not changed, nor has the information itself. Everything has however been genericized, which is necessary. > > Both functionalities have been genericized. This results in all parameters > > being able to be used with all types of devices. This is inherent to the > > EAL becoming bus-agnostic. > > > > Now, it is absolutely possible to rename for example -w as --dev, as it > > is the expected behavior from users. This however should be discussed by > > the community, last time I talked about the possibility of switching the > > default of the PCI bus to whitelist mode the community wasn't all that > > enthused by the prospect. > > > > Finally, I do not like the idea of a special devarg just for declaring > > explicitly buses for devices. The bus is not a device modifier, nor is > > it a driver parameter. The bus is a way to define the location of the > > device on the system. Adding a special "bus=" devargs means having some > > preprocessing done on devargs upon rte_devargs allocation. This was > > already abused by the bonding PMD with the driver= parameter. I do not > > support this and did not want to repeat it. Passing down the device args > > is a simple process and we should keep it as simple as possible. > > > > I know you do not like having the bus as part of the device name. > > As a compromise, I made the current system flexible and allowed the legacy > > device definition to be kept. > > > > However with a purely generic process, it is necessary to at least offer > > the possibility to the user to explicitly use a bus, as nothing prevents > > conflicting device names from existing. > > > >> > [2]: http://dpdk.org/ml/archives/dev/2017-May/065670.html > > > >> > This explicit bus designation is optional; no evolution is currently > >> > forced on users to migrate to this new format. The separating character > >> > is > >> > arbitrary and can be any character illegal within a bus name. > >> > Subsequently, what is allowed within a bus name has been formally > >> > defined and is now enforced. > >> > > >> > [1]: http://dpdk.org/ml/archives/dev/2017-May/065634.html > >> > [2]: http://dpdk.org/ml/archives/dev/2017-May/065670.html > >> > > >> > This patchset depends on: > >> > > >> > bus: attach / detach API > >> > http://dpdk.org/ml/archives/dev/2017-May/066330.html > >> > http://dpdk.org/dev/patchwork/patch/24489/ > >> > > >> > Gaetan Rivet (9): > >> > bus: fix bus name registration > >> > bus: verify bus name on registration > >> > bus: introduce parsing functionality > >> > vdev: implement parse bus operation > >> > pci: implement parse bus operation > >> > bus: add helper to find bus from a name > >> > bus: add helper to find a bus from a device name > >> > vdev: expose bus name > >> > devargs: parse bus info > >> > > >> > lib/librte_eal/bsdapp/eal/rte_eal_version.map | 8 +++ > >> > lib/librte_eal/common/eal_common_bus.c | 47 +++++++++++++++++ > >> > lib/librte_eal/common/eal_common_devargs.c | 17 +++++- > >> > lib/librte_eal/common/eal_common_pci.c | 19 +++++++ > >> > lib/librte_eal/common/eal_common_vdev.c | 70 > >> > ++++++++++++++----------- > >> > lib/librte_eal/common/eal_private.h | 16 ++++++ > >> > lib/librte_eal/common/include/rte_bus.h | 49 ++++++++++++++++- > >> > lib/librte_eal/common/include/rte_devargs.h | 3 ++ > >> > lib/librte_eal/common/include/rte_vdev.h | 2 + > >> > lib/librte_eal/linuxapp/eal/rte_eal_version.map | 8 +++ > >> > 10 files changed, 205 insertions(+), 34 deletions(-) > >> > > >> > -- > >> > 2.1.4 > >> > > > > > -- > > Gaėtan Rivet > > 6WIND -- Gaëtan Rivet 6WIND
