Re: [dpdk-dev] [PATCH v1 5/6] crypto/ccp: enable IOMMU for CCP

[Jerin Jacob <jerinjacobk@gmail.com>]

On Tue, Oct 15, 2019 at 2:05 PM Somalapuram, Amaranath
<Amaranath.Somalapuram@amd.com> wrote:
>
> Problem statement: As of now vdev device do not support IOMMU.
> vdev device used to custom solution, even for software drives like openssl uses vdev.

I spend some time going through the driver.

#The ideal architecture of this driver would have been to introduce a
bus driver(see drivers/bus/ifpga/) which does all the PCI
probes(drivers/crypto/ccp/rte_ccp_pmd.c and
drivers/crypto/ccp/ccp_pci.c)
and arrange the devices on the bus scan and enable "non bus" specific
driver crypto driver. So that no pci probe etc in crypto driver.
# On the upside, You DONT need to give vdev= on eal arguments, on AMD
machines it can probe the crypto devices automatically and probe the
crypto driver
# I dont think, it is specific to vdev IOMMU support, If would have
been PCI/Any bus driver, you would have similar changes. Right?
#  Major portion of this patch does following
+               if (iommu_mode == 2)
+                       pst.src_addr = (phys_addr_t)rte_mem_virt2iova(
+                                       (void *) lsb_buf);
+               else
+                       pst.src_addr = (phys_addr_t)rte_mem_virt2phy(
+                                       (void *) lsb_buf);
+

Since the following check already present common code, Do we need the
above check, just calling rte_mem_virt2iova() is enough. Right?

rte_iova_t
rte_mem_virt2iova(const void *virtaddr)
{
        if (rte_eal_iova_mode() == RTE_IOVA_VA)
                return (uintptr_t)virtaddr;
        return rte_mem_virt2phy(virtaddr);
}










> I feel its not advisable to put iommu in vdev.
> moving the changes to vdev will effect rest of the vdev drives.
> That will be big efforts. Every vdev drivers has their own implementation. Need better design to move it to vdev or common place.
>
> Regards,
> S.Amarnath
>
> -----Original Message-----
> From: Jerin Jacob <jerinjacobk@gmail.com>
> Sent: Tuesday, October 15, 2019 1:47 PM
> To: Somalapuram, Amaranath <Amaranath.Somalapuram@amd.com>
> Cc: dev@dpdk.org; stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v1 5/6] crypto/ccp: enable IOMMU for CCP
>
> [CAUTION: External Email]
>
> On Tue, Oct 15, 2019 at 12:32 PM <asomalap@amd.com> wrote:
> >
> > From: Amaranath Somalapuram <asomalap@amd.com>
> >
> > CCP use vdev framework, and vdev framework don’t support IOMMU.
> > Adding custom IOMMU support for AMD CCP drives.
> > Cc: stable@dpdk.org
> >
> > +       if (iommu_mode == 2)
> > +               pci->kdrv = RTE_KDRV_VFIO;
> > +       else if (iommu_mode == 0)
> > +               pci->kdrv = RTE_KDRV_IGB_UIO;
> > +       else if (iommu_mode == 1)
> > +               pci->kdrv = RTE_KDRV_UIO_GENERIC;
>
> The crypto driver should not have iommu mode-specific handling.
> I am not sure about the problem statement. If the problem is, iommu support for PCI based vdev device then move the solution to common layer so that everyone can use it. If not, please share the problem statement