Re: [PATCH v2] eal/linux: force iova-mode va without pa available

[Christian Ehrhardt <christian.ehrhardt@canonical.com>]

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On Wed, Nov 29, 2023 at 10:51 PM David Christensen <drc@linux.vnet.ibm.com>
wrote:

>
>
> On 11/24/23 2:09 AM, christian.ehrhardt@canonical.com wrote:
> > From: David Wilder <dwilder@us.ibm.com>
> >
> > When using --no-huge option physical address are not guaranteed
> > to be persistent.
> >
> > This change effectively makes "--no-huge" the same as
> > "--no-huge --iova-mode=va".
> >
> > When --no-huge is used (or any other condition making physical
> > addresses unavailable) setting --iova-mode=pa will have no effect.
> >
> > Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
> > ---
> >   doc/guides/prog_guide/env_abstraction_layer.rst |  9 ++++++---
> >   lib/eal/linux/eal.c                             | 16 ++++++++++------
> >   2 files changed, 16 insertions(+), 9 deletions(-)
> >
> > diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst
> b/doc/guides/prog_guide/env_abstraction_layer.rst
> > index 6debf54efb..20c7355e0f 100644
> > --- a/doc/guides/prog_guide/env_abstraction_layer.rst
> > +++ b/doc/guides/prog_guide/env_abstraction_layer.rst
> > @@ -559,9 +559,12 @@ IOVA Mode is selected by considering what the
> current usable Devices on the
> >   system require and/or support.
> >
> >   On FreeBSD, RTE_IOVA_PA is always the default. On Linux, the IOVA mode
> is
> > -detected based on a 2-step heuristic detailed below.
> > +detected based on a heuristic detailed below.
> >
> > -For the first step, EAL asks each bus its requirement in terms of IOVA
> mode
> > +For the first step, if no Physical Addresses are available RTE_IOVA_VA
> is
> > +selected.
> > +
> > +Then EAL asks each bus its requirement in terms of IOVA mode
> >   and decides on a preferred IOVA mode.
> >
> >   - if all buses report RTE_IOVA_PA, then the preferred IOVA mode is
> RTE_IOVA_PA,
> > @@ -575,7 +578,7 @@ and decides on a preferred IOVA mode.
> >   If the buses have expressed no preference on which IOVA mode to pick,
> then a
> >   default is selected using the following logic:
> >
> > -- if physical addresses are not available, RTE_IOVA_VA mode is used
> > +- if enable_iova_as_pa was not set at build RTE_IOVA_VA mode is used
> >   - if /sys/kernel/iommu_groups is not empty, RTE_IOVA_VA mode is used
> >   - otherwise, RTE_IOVA_PA mode is used
> >
> > diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c
> > index 57da058cec..2f1fce3c54 100644
> > --- a/lib/eal/linux/eal.c
> > +++ b/lib/eal/linux/eal.c
> > @@ -1067,6 +1067,16 @@ rte_eal_init(int argc, char **argv)
> >
> >       phys_addrs = rte_eal_using_phys_addrs() != 0;
> >
> > +     if (!phys_addrs) {
> > +             /* if we have no access to physical addresses, pick IOVA
> as VA mode. */
> > +             if (internal_conf->iova_mode == RTE_IOVA_PA)
> > +                     RTE_LOG(WARNING, EAL, "WARNING: --iova-mode=pa,
> but Physical addresses are unavailable, selecting IOVA as VA mode.\n");
> > +             else
> > +                     RTE_LOG(DEBUG, EAL, "Physical addresses are
> unavailable, selecting IOVA as VA mode.\n");
> > +             internal_conf->iova_mode = RTE_IOVA_VA;
> > +             rte_eal_get_configuration()->iova_mode =
> internal_conf->iova_mode;
> > +     }
> > +
> >       /* if no EAL option "--iova-mode=<pa|va>", use bus IOVA scheme */
> >       if (internal_conf->iova_mode == RTE_IOVA_DC) {
> >               /* autodetect the IOVA mapping mode */
> > @@ -1078,12 +1088,6 @@ rte_eal_init(int argc, char **argv)
> >                       if (!RTE_IOVA_IN_MBUF) {
> >                               iova_mode = RTE_IOVA_VA;
> >                               RTE_LOG(DEBUG, EAL, "IOVA as VA mode is
> forced by build option.\n");
> > -                     } else if (!phys_addrs) {
> > -                             /* if we have no access to physical
> addresses,
> > -                              * pick IOVA as VA mode.
> > -                              */
> > -                             iova_mode = RTE_IOVA_VA;
> > -                             RTE_LOG(DEBUG, EAL, "Physical addresses
> are unavailable, selecting IOVA as VA mode.\n");
> >                       } else if (is_iommu_enabled()) {
> >                               /* we have an IOMMU, pick IOVA as VA mode
> */
> >                               iova_mode = RTE_IOVA_VA;
>
> What tests are you running that generate an error without explicitly
> selecting the iova-mode?  When I run the fast-tests I see the system
> correctly selecting VA without any additional command-line parameters
> when running 23.11:
>
>
Hi, we run the tests as they are defined in debian/ubuntu autopkgtest, here
a full log:


https://autopkgtest.ubuntu.com/results/autopkgtest-noble-paelzer-dpdk-23.11-test-builds/noble/ppc64el/d/dpdk/20231123_134814_ed029@/log.gz

Fasttests, just like yours, fail for us.
But this is a virtual test env that might not be as powerful as yours.

But as I've said, consider this one withdrawn and the one just fixing the
test config preferred.


> 21:47:05 DPDK_TEST=acl_autotest MALLOC_PERTURB_=201
> /home/drc/src/dpdk/build/app/dpdk-test --no-huge -m 2048
> ----------------------------------- output
> -----------------------------------
> stdout:
> RTE>>acl_autotest
> acl context <acl_ctx>@0x179cbd300
>    socket_id=-1
>    alg=5
>    first_load_sz=0
>    max_rules=196608
>    rule_size=128
>    num_rules=0
>    num_categories=0
>    num_tries=0
> acl context <acl_ctx>@0x179cbd300
>    socket_id=-1
>    alg=5
>    first_load_sz=0
>    max_rules=196608
>    rule_size=128
>    num_rules=0
>    num_categories=0
>    num_tries=0
> running test_convert_rules(acl_ipv4vlan_tuple)
> running test_convert_rules(acl_ipv4vlan_tuple,
> RTE_ACL_FIELD_TYPE_BITMASK type for IPv4)
> running test_convert_rules(acl_ipv4vlan_tuple, RTE_ACL_FIELD_TYPE_RANGE
> type for IPv4)
> running test_convert_rules(acl_ipv4vlan_tuple: swap VLAN and PORTs order)
> running test_convert_rules(acl_ipv4vlan_tuple: swap SRC and DST IPv4 order)
> test_u32_range#1704 starting range test from 0 to 264192
> Test OK
> RTE>>
> stderr:
> EAL: Detected CPU lcores: 128
> EAL: Detected NUMA nodes: 2
> EAL: Detected static linkage of DPDK
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'VA'
>
> Dave
>


-- 
Christian Ehrhardt
Director of Engineering, Ubuntu Server
Canonical Ltd

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