On Thu, Sep 01, 2016 at 10:41:22AM -0700, Stephen Hemminger wrote: > On Thu, 1 Sep 2016 13:35:19 -0400 > Neil Horman <nhorman at tuxdriver.com> wrote: > > > On Thu, Sep 01, 2016 at 12:55:27PM +0000, Trahe, Fiona wrote: > > > Hi Neil and Olivier, > > > > > > > -----Original Message----- > > > > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Olivier Matz > > > > Sent: Wednesday, August 31, 2016 2:40 PM > > > > To: Neil Horman <nhorman at tuxdriver.com> > > > > Cc: dev at dpdk.org; thomas.monjalon at 6wind.com > > > > Subject: Re: [dpdk-dev] [dpdk-dev, RFC] drivers: advertise kmod > > > > dependencies > > > > in pmdinfo > > > > > > > > Hi Neil, > > > > > > > > On 08/31/2016 03:27 PM, Neil Horman wrote: > > > > > On Wed, Aug 31, 2016 at 11:21:18AM +0200, Olivier Matz wrote: > > > > >> Hi Neil, > > > > >> > > > > >> On 08/30/2016 03:23 PM, Neil Horman wrote: > > > > >>> On Fri, Aug 26, 2016 at 03:20:46PM +0200, Olivier Matz wrote: > > > > >>>> Add a new macro DRIVER_REGISTER_KMOD_DEP() that allows a driver to > > > > >>>> declare the list of kernel modules required to run properly. > > > > >>>> > > > > >>>> Today, most PCI drivers require uio/vfio. > > > > >>>> > > > > >>>> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com> > > > > >>>> > > > > >>>> --- > > > > >>>> In this RFC, I supposed that all PCI drivers require a the loading > > > > >>>> of a > > > > >>>> uio/vfio module (except mlx*), this may be wrong. > > > > >>>> Comments are welcome! > > > > >>>> > > > > >>>> > > > > >>>> buildtools/pmdinfogen/pmdinfogen.c | 1 + > > > > >>>> buildtools/pmdinfogen/pmdinfogen.h | 1 + > > > > >>>> drivers/crypto/qat/rte_qat_cryptodev.c | 2 ++ > > > > >>>> drivers/net/bnx2x/bnx2x_ethdev.c | 4 ++++ > > > > >>>> drivers/net/bnxt/bnxt_ethdev.c | 2 ++ > > > > >>>> drivers/net/cxgbe/cxgbe_ethdev.c | 2 ++ > > > > >>>> drivers/net/e1000/em_ethdev.c | 2 ++ > > > > >>>> drivers/net/e1000/igb_ethdev.c | 4 ++++ > > > > >>>> drivers/net/ena/ena_ethdev.c | 2 ++ > > > > >>>> drivers/net/enic/enic_ethdev.c | 2 ++ > > > > >>>> drivers/net/fm10k/fm10k_ethdev.c | 2 ++ > > > > >>>> drivers/net/i40e/i40e_ethdev.c | 2 ++ > > > > >>>> drivers/net/i40e/i40e_ethdev_vf.c | 2 ++ > > > > >>>> drivers/net/ixgbe/ixgbe_ethdev.c | 4 ++++ > > > > >>>> drivers/net/mlx4/mlx4.c | 2 ++ > > > > >>>> drivers/net/mlx5/mlx5.c | 3 +++ > > > > >>>> drivers/net/nfp/nfp_net.c | 2 ++ > > > > >>>> drivers/net/qede/qede_ethdev.c | 4 ++++ > > > > >>>> drivers/net/szedata2/rte_eth_szedata2.c | 2 ++ > > > > >>>> drivers/net/thunderx/nicvf_ethdev.c | 2 ++ > > > > >>>> drivers/net/virtio/virtio_ethdev.c | 2 ++ > > > > >>>> drivers/net/vmxnet3/vmxnet3_ethdev.c | 2 ++ > > > > >>>> lib/librte_eal/common/include/rte_dev.h | 14 ++++++++++++++ > > > > >>>> tools/dpdk-pmdinfo.py | 5 ++++- > > > > >>>> 24 files changed, 69 insertions(+), 1 deletion(-) > > > > >>>> > > > > >>> > > > > >>> Generally speaking, I like the idea, it makes sense to me in terms > > > > >>> of using > > > > >>> pmdinfo to export this information > > > > >>> > > > > >>> That said, This may need to be a set of macros. By that I mean > > > > >>> (and correct > > > > me > > > > >>> if I'm wrong here), but the relationship between pmd's and kernel > > > > >>> modules > > > > is in > > > > >>> some cases, more complex than a 'requires' or 'depends' > > > > >>> relationship. That > > > > is > > > > >>> to say, some pmd may need user space hardware access, but can use > > > > >>> either > > > > uio OR > > > > >>> vfio, but doesn't need both, and can continue to function if only > > > > >>> one is > > > > >>> available. Other PMD's may be able to use vfio or uio, but can > > > > >>> still function > > > > >>> without either. And some, as your patch implements, simply require > > > > >>> one or > > > > the > > > > >>> other to function. As such it seems like you may want a few > > > > >>> macros, in the > > > > form > > > > >>> of: > > > > >>> > > > > >>> DRIVER_REGISTER_KMOD_REQUEST - List of modules to attempt loading, > > > > ignore any > > > > >>> failures > > > > >>> DRIVER_REGISTER_KMOD_REQUIRE - List of modules required to be > > > > loaded after > > > > >>> request macro completes, fail if any are not loaded > > > > >>> > > > > >>> Thats just spitballing, mind you, theres probably a better way to > > > > >>> do it, but > > > > the > > > > >>> idea is to list a set of modules you would like to have, and then > > > > >>> create a > > > > >>> parsable syntax to describe the modules that need to be loaded > > > > >>> after the > > > > request > > > > >>> is complete so that you can accurately codify the situations I > > > > >>> described > > > > above. > > > > >> > > > > >> Thank you for your feedback. > > > > >> However, I'm not sure I'm perfectly getting what you suggest. > > > > >> > > > > >> Do you think some PMDs could request a kernel module without really > > > > >> requiring it? Do you have an example in mind? > > > > >> > > > > > Yes, thats precisely it. The most clear example I could think of > > > > > (though I'm > > > > > not sure if any pmd currently supports this), is a pmd that supports > > > > > both UIO > > > > > and VFIO communication with the kernel. Such a PMD requires that one > > > > > of > > > > those > > > > > two modules be loaded, but only one (i.e. both are not required), so > > > > > if only > > > > the > > > > > uio kernel module loads is a success case, likewise if only the vfio > > > > > module > > > > > loads can be treated as success. Both loading are clearly > > > > > successful. Only if > > > > > neither load do we have a failure case. I'm suggesting that the > > > > > grammer that > > > > > your exports define should take those cases into account. Its not > > > > > always as > > > > > simple as "I must have the following modules" > > > > > > > > > >> The syntax I've submitted lets you define several lists of modules, > > > > >> so > > > > >> that the user or the script that starts the application can decide > > > > >> which > > > > >> kmod list is better according to the environment. > > > > >> > > > > > If you have a human intervening in the module load process, sure, > > > > > then its > > > > fine. > > > > > But it seems that this particular feature that you're implemnting > > > > > might have > > > > > automated uses. That is to say the dpdk core library might be > > > > > interested in > > > > > parsing this particular information to direct module autoloading, and > > > > > if thats > > > > > desireable then you need to define these lists such that you can > > > > > codify failure > > > > > and success conditions. > > > > > > > > > >> For example, most drivers will advertise > > > > >> "uio,igb_uio:uio,uio_pci_generic:vfio,vfio-pci", and the user or > > > > >> script > > > > >> will have to choose between loading: > > > > >> - uio igb_uio > > > > >> - uio uio_pci_generic > > > > >> - vfio vfio-pci > > > > >> > > > > > Oh, I see, so your list is a colon delimited list of module load > > > > > sets, where at > > > > > least one set must succeed by loading all modules in its set, but the > > > > > failure of > > > > > any one set isn't fatal to the process? e.g. a string like this: > > > > > > > > > > uio,igb_uio:vfio,vfio-pci > > > > > > > > > > could be interpreted to mean "I must load (uio AND igb_uio) OR (vfio > > > > > AND > > > > > vfio-pci). If the evaluation of that statement results in false, > > > > > then the > > > > > operation fails, otherwise it succedes. > > > > > > > > > > If thats the case, then, apologies, we're on the same page, and this > > > > > will work > > > > > just fine. > > > > > > > > Yep, that's the idea. > > > > > > > > Colon and commas are the best separators I've thought about, but any > > > > idea to make the syntax clearer is welcome ;) > > > > > > > > Maybe a syntax like is clearer: > > > > "(mod1 & mod2)|(mod3 & mod4)" ? > > > > But it would let the user think that more complex expressions are valid, > > > > like "(mod1 & (mod2 | mod3)) | mod4", which is probably overkill. > > > > > > > > Regards, > > > > Olivier > > > > > > This RFC seems like a good idea - and something the Intel QuickAssist PMD > > > could benefit from. > > > However the (mod1 & mod2) can handle the QAT case better in my opinion. > > > i.e. > > > as well as needing one of > > > * uio igb_uio > > > * uio uio_pci_generic > > > * vfio vfio-pci > > > QAT PMD also needs one of (depending on which physical device is plugged) > > > * qat_dh895xcc > > > * qat_c62x > > > * qat_c3xxx > > > > > > So the original syntax would result in a very long list of possible > > > variations. > > > What really reflects the dependencies would be > > > ((uio & igb_uio) | (uio & uio_pci_generic) | (vfio & vfio_pci)) & > > > (qat_dh895xcc | qat_c62x | qat_c3xxx) > > > > > Ah, I didn't consider that hardware specifics might create a use case where > > a > > pmd must have one or more kernel modules available for hw support. Perhaps > > it > > is worthwhile to automate hardware support - that is to say, any module > > loading > > script should automatically look at the pci table exported from a pmd, and, > > if > > found, load any modules that claim support for that device:vendor tuple? > > Though > > that might break in the case of uio, if there are separate driver modules > > that > > support native hardware and uio access. > > I ended up writing a script that went the other way. > First look at the hardware and load VFIO if IOMMU is available. > Then look for special driver needed for Xen and HyperV > Lastly fallback to loading igb_uio if no VFIO and PCI device present. > > In other words it is a system not driver issue. > That sounds like a reasonable approach, yes. Neil
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