[dpdk-dev] [PATCH] pci/linux: use RTE_IOVA_VA whenever possible
Jerin Jacob
jerin.jacob at caviumnetworks.com
Thu Oct 11 12:47:12 CEST 2018
-----Original Message-----
> Date: Thu, 11 Oct 2018 11:26:05 +0100
> From: "Burakov, Anatoly" <anatoly.burakov at intel.com>
> To: Alejandro Lucero <alejandro.lucero at netronome.com>,
> dariusz.stojaczyk at intel.com
> CC: dev <dev at dpdk.org>, Santosh Shukla <santosh.shukla at caviumnetworks.com>,
> Hemant Agrawal <hemant.agrawal at nxp.com>, Jerin Jacob
> <jerin.jacob at caviumnetworks.com>, Maxime Coquelin
> <maxime.coquelin at redhat.com>, chas3 at att.com
> Subject: Re: [dpdk-dev] [PATCH] pci/linux: use RTE_IOVA_VA whenever possible
> User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
> Thunderbird/52.9.1
>
>
> On 11-Oct-18 11:00 AM, Alejandro Lucero wrote:
> > On Fri, Sep 7, 2018 at 3:55 PM Darek Stojaczyk <dariusz.stojaczyk at intel.com>
> > wrote:
> >
> > > This allows DPDK to use RTE_IOVA_VA with VFIO/UIO-bound PCI
> > > devices present on the system, but not attached to any
> > > rte_pci_driver at the time of init.
> > >
> > > So far we used RTE_IOVA_VA whenever there was at least one
> > > device attached to a driver with an RTE_PCI_DRV_IOVA_AS_VA flag,
> > > meaning that other drivers which didn't explicitly report such
> > > flag could have been forced to work in RTE_IOVA_VA as well.
> > >
> >
> > This is the opposite. Just one device not being able to use IOVA VA makes
> > all to use IOVA PA.
> >
> >
> > >
> > > This patch makes the RTE_PCI_DRV_IOVA_AS_VA explicitly a hint.
> > > If it's set, but RTE_IOVA_VA cannot be used, then EAL will print
> > > a proper warning.
> > >
> > > Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk at intel.com>
> > > ---
> > > drivers/bus/pci/linux/pci.c | 11 +++++------
> > > 1 file changed, 5 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
> > > index 04648ac93..961e24024 100644
> > > --- a/drivers/bus/pci/linux/pci.c
> > > +++ b/drivers/bus/pci/linux/pci.c
> > > @@ -534,7 +534,7 @@ pci_one_device_bound_uio(void)
> > > * Any one of the device has iova as va
> > > */
> > > static inline int
> > > -pci_one_device_has_iova_va(void)
> > > +pci_one_device_want_iova_va(void)
> > > {
> > > struct rte_pci_device *dev = NULL;
> > > struct rte_pci_driver *drv = NULL;
> > > @@ -635,7 +635,7 @@ rte_pci_get_iommu_class(void)
> > > {
> > > bool is_bound;
> > > bool is_vfio_noiommu_enabled = true;
> > > - bool has_iova_va;
> > > + bool want_iova_va;
> > > bool is_bound_uio;
> > > bool iommu_no_va;
> > >
> > > @@ -643,7 +643,7 @@ rte_pci_get_iommu_class(void)
> > > if (!is_bound)
> > > return RTE_IOVA_DC;
> > >
> > > - has_iova_va = pci_one_device_has_iova_va();
> > > + want_iova_va = pci_one_device_want_iova_va();
> > > is_bound_uio = pci_one_device_bound_uio();
> > > iommu_no_va = !pci_devices_iommu_support_va();
> > > #ifdef VFIO_PRESENT
> > > @@ -651,11 +651,10 @@ rte_pci_get_iommu_class(void)
> > > true : false;
> > > #endif
> > >
> > > - if (has_iova_va && !is_bound_uio && !is_vfio_noiommu_enabled &&
> > > - !iommu_no_va)
> > > + if (!is_bound_uio && !is_vfio_noiommu_enabled && !iommu_no_va)
> > > return RTE_IOVA_VA;
> > >
> >
> > This is wrong. A device not able to work with IOVA VA will fail.
> >
> >
> > >
> > > - if (has_iova_va) {
> > > + if (want_iova_va) {
> > > RTE_LOG(WARNING, EAL, "Some devices want iova as va but pa
> > > will be used because.. ");
> > > if (is_vfio_noiommu_enabled)
> > > RTE_LOG(WARNING, EAL, "vfio-noiommu mode
> > > configured\n");
> > > --
> > > 2.17.1
> > >
> > >
> >
>
> For these cases, i think the explicit IOVA mode on command line should
> work better. If the device has not reported IOVA as VA capability, it is
> to be assumed unsupported.
Yes.
>
> --
> Thanks,
> Anatoly
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