| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <c009c4e5-418c-444d-8609-0475f3864ed9@linux.dev>
Date: Sun, 11 May 2025 06:52:59 +0200
From: Zhu Yanjun <yanjun.zhu@...ux.dev>
To: Daisuke Matsuda <dskmtsd@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-rdma@...r.kernel.org,
leon@...nel.org, jgg@...pe.ca, zyjzyj2000@...il.com
Subject: Re: [PATCH for-next v2 1/2] RDMA/rxe: Implement synchronous prefetch
for ODP MRs
在 2025/5/11 4:06, Daisuke Matsuda 写道:
>
> On 2025/05/10 17:04, Greg Sword wrote:
>> On Sat, May 10, 2025 at 3:19 PM Daisuke Matsuda <dskmtsd@...il.com>
>> wrote:
>>>
>>> On 2025/05/10 13:43, Zhu Yanjun wrote:
>>>>
>>>> 在 2025/5/10 4:46, Daisuke Matsuda 写道:
>>>>> On 2025/05/10 0:19, Zhu Yanjun wrote:
>>>>>> On 03.05.25 15:42, Daisuke Matsuda wrote:
>>>>>>> Minimal implementation of ibv_advise_mr(3) requires synchronous
>>>>>>> calls being
>>>>>>> successful with the IBV_ADVISE_MR_FLAG_FLUSH flag. Asynchronous
>>>>>>> requests,
>>>>>>> which are best-effort, will be added subsequently.
>>>>>>>
>>>>>>> Signed-off-by: Daisuke Matsuda <dskmtsd@...il.com>
>>>>>>> ---
>>>>>>> drivers/infiniband/sw/rxe/rxe.c | 7 +++
>>>>>>> drivers/infiniband/sw/rxe/rxe_loc.h | 10 ++++
>>>>>>> drivers/infiniband/sw/rxe/rxe_odp.c | 86 +++++++++++++++++++++
>>>>>>> ++++++++
>>>>>>> 3 files changed, 103 insertions(+)
>>>>>>>
>>>>>>> diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/
>>>>>>> infiniband/sw/rxe/rxe.c
>>>>>>> index 3a77d6db1720..e891199cbdef 100644
>>>>>>> --- a/drivers/infiniband/sw/rxe/rxe.c
>>>>>>> +++ b/drivers/infiniband/sw/rxe/rxe.c
>>>>>>> @@ -34,6 +34,10 @@ void rxe_dealloc(struct ib_device *ib_dev)
>>>>>>> mutex_destroy(&rxe->usdev_lock);
>>>>>>> }
>>>>>>> +static const struct ib_device_ops rxe_ib_dev_odp_ops = {
>>>>>>> + .advise_mr = rxe_ib_advise_mr,
>>>>>>> +};
>>>>>>> +
>>>>>>> /* initialize rxe device parameters */
>>>>>>> static void rxe_init_device_param(struct rxe_dev *rxe, struct
>>>>>>> net_device *ndev)
>>>>>>> {
>>>>>>> @@ -103,6 +107,9 @@ static void rxe_init_device_param(struct
>>>>>>> rxe_dev *rxe, struct net_device *ndev)
>>>>>>> rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |=
>>>>>>> IB_ODP_SUPPORT_SRQ_RECV;
>>>>>>> rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |=
>>>>>>> IB_ODP_SUPPORT_FLUSH;
>>>>>>> rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |=
>>>>>>> IB_ODP_SUPPORT_ATOMIC_WRITE;
>>>>>>> +
>>>>>>> + /* set handler for ODP prefetching API -
>>>>>>> ibv_advise_mr(3) */
>>>>>>> + ib_set_device_ops(&rxe->ib_dev, &rxe_ib_dev_odp_ops);
>>>>>>> }
>>>>>>> }
>>>>>>> diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/
>>>>>>> infiniband/sw/rxe/rxe_loc.h
>>>>>>> index f7dbb9cddd12..21b070f3dbb8 100644
>>>>>>> --- a/drivers/infiniband/sw/rxe/rxe_loc.h
>>>>>>> +++ b/drivers/infiniband/sw/rxe/rxe_loc.h
>>>>>>> @@ -197,6 +197,9 @@ enum resp_states rxe_odp_atomic_op(struct
>>>>>>> rxe_mr *mr, u64 iova, int opcode,
>>>>>>> int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
>>>>>>> unsigned int length);
>>>>>>> enum resp_states rxe_odp_do_atomic_write(struct rxe_mr *mr,
>>>>>>> u64 iova, u64 value);
>>>>>>> +int rxe_ib_advise_mr(struct ib_pd *pd, enum
>>>>>>> ib_uverbs_advise_mr_advice advice,
>>>>>>> + u32 flags, struct ib_sge *sg_list, u32 num_sge,
>>>>>>> + struct uverbs_attr_bundle *attrs);
>>>>>>> #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
>>>>>>> static inline int
>>>>>>> rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64
>>>>>>> length, u64 iova,
>>>>>>> @@ -225,6 +228,13 @@ static inline enum resp_states
>>>>>>> rxe_odp_do_atomic_write(struct rxe_mr *mr,
>>>>>>> {
>>>>>>> return RESPST_ERR_UNSUPPORTED_OPCODE;
>>>>>>> }
>>>>>>> +static inline int rxe_ib_advise_mr(struct ib_pd *pd, enum
>>>>>>> ib_uverbs_advise_mr_advice advice,
>>>>>>> + u32 flags, struct ib_sge *sg_list, u32 num_sge,
>>>>>>> + struct uverbs_attr_bundle *attrs)
>>>>>>> +{
>>>>>>> + return -EOPNOTSUPP;
>>>>>>> +}
>>>>>>> +
>>>>>>> #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
>>>>>>> #endif /* RXE_LOC_H */
>>>>>>> diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/
>>>>>>> infiniband/sw/rxe/rxe_odp.c
>>>>>>> index 6149d9ffe7f7..e5c60b061d7e 100644
>>>>>>> --- a/drivers/infiniband/sw/rxe/rxe_odp.c
>>>>>>> +++ b/drivers/infiniband/sw/rxe/rxe_odp.c
>>>>>>> @@ -424,3 +424,89 @@ enum resp_states
>>>>>>> rxe_odp_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value)
>>>>>>> return RESPST_NONE;
>>>>>>> }
>>>>>>> +
>>>>>>> +static int rxe_ib_prefetch_sg_list(struct ib_pd *ibpd,
>>>>>>> + enum ib_uverbs_advise_mr_advice advice,
>>>>>>> + u32 pf_flags, struct ib_sge *sg_list,
>>>>>>> + u32 num_sge)
>>>>>>> +{
>>>>>>> + struct rxe_pd *pd = container_of(ibpd, struct rxe_pd, ibpd);
>>>>>>> + unsigned int i;
>>>>>>> + int ret = 0;
>>>>>>> +
>>>>>>> + for (i = 0; i < num_sge; ++i) {
>>>>>>> + struct rxe_mr *mr;
>>>>>>> + struct ib_umem_odp *umem_odp;
>>>>>>> +
>>>>>>> + mr = lookup_mr(pd, IB_ACCESS_LOCAL_WRITE,
>>>>>>> + sg_list[i].lkey, RXE_LOOKUP_LOCAL);
>>>>>>> +
>>>>>>> + if (IS_ERR(mr)) {
>>>>>>> + rxe_dbg_pd(pd, "mr with lkey %x not found\n",
>>>>>>> sg_list[i].lkey);
>>>>>>> + return PTR_ERR(mr);
>>>>>>> + }
>>>>>>> +
>>>>>>> + if (advice == IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_WRITE &&
>>>>>>> + !mr->umem->writable) {
>>>>>>> + rxe_dbg_mr(mr, "missing write permission\n");
>>>>>>> + rxe_put(mr);
>>>>>>> + return -EPERM;
>>>>>>> + }
>>>>>>> +
>>>>>>> + ret = rxe_odp_do_pagefault_and_lock(mr, sg_list[i].addr,
>>>>>>> + sg_list[i].length, pf_flags);
>>>>>>> + if (ret < 0) {
>>>>>>> + if (sg_list[i].length == 0)
>>>>>>> + continue;
>>>>>>> +
>>>>>>> + rxe_dbg_mr(mr, "failed to prefetch the mr\n");
>>>>>>> + rxe_put(mr);
>>>>>>> + return ret;
>>>>>>> + }
>>>>>>> +
>>>>>>> + umem_odp = to_ib_umem_odp(mr->umem);
>>>>>>> + mutex_unlock(&umem_odp->umem_mutex);
>>>>>>> +
>>>>>>> + rxe_put(mr);
>>>>>>> + }
>>>>>>> +
>>>>>>> + return 0;
>>>>>>> +}
>>>>>>> +
>>>>>>> +static int rxe_ib_advise_mr_prefetch(struct ib_pd *ibpd,
>>>>>>> + enum ib_uverbs_advise_mr_advice advice,
>>>>>>> + u32 flags, struct ib_sge *sg_list, u32
>>>>>>> num_sge)
>>>>>>> +{
>>>>>>> + u32 pf_flags = RXE_PAGEFAULT_DEFAULT;
>>>>>>> +
>>>>>>> + if (advice == IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH)
>>>>>>> + pf_flags |= RXE_PAGEFAULT_RDONLY;
>>>>>>> +
>>>>>>> + if (advice == IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_NO_FAULT)
>>>>>>> + pf_flags |= RXE_PAGEFAULT_SNAPSHOT;
>>>>>>> +
>>>>>>> + /* Synchronous call */
>>>>>>> + if (flags & IB_UVERBS_ADVISE_MR_FLAG_FLUSH)
>>>>>>> + return rxe_ib_prefetch_sg_list(ibpd, advice, pf_flags,
>>>>>>> sg_list,
>>>>>>> + num_sge);
>>>>>>> +
>>>>>>> + /* Asynchronous call is "best-effort" */
>>>>>>
>>>>>> Asynchronous call is not implemented now, why does this comment
>>>>>> appear?
>>>>>
>>>>> Even without the 2nd patch, async calls are reported as successful.
>>>>
>>>>
>>>> Async call is not implemented. How to call "async calls are reported
>>>> as successful"?
>>>
>>> Please see the manual.
>>> cf. https://manpages.debian.org/testing/libibverbs-dev/
>>> ibv_advise_mr.3.en.html
>>>
>>> If IBV_ADVISE_MR_FLAG_FLUSH is not given to 'flags' parameter,
>>> then this function 'rxe_ib_advise_mr_prefetch()' simply returns 0.
>>> Consequently, ibv_advise_mr(3) and underlying ioctl(2) get no error.
>>> This behaviour is allowd in the spec as I quoted in the last reply.
>>
>> The functionality wasn't implemented, you added the comments first.
>> You're still weaseling when people point this out.
>>
>>>
>>> It might be nice to return -EOPNOTSUPP just below the comment instead,
>>> but not doing so is acceptable according to the spec. Additionally,
>>> such change will be overwritten in the next patch after all.
>>
>> Move comments to the next patch. In this patch, return -EOPNOTSUPP.
>
> Any opinion from Zhu?
> I may post a new revision to change the intermediate code,
> but the final result after applying the patchset will be the same.
> You are the maintainer of rxe, so I will follow that.
Thanks a lot. I am fine with your commit.
Please "Move comments to the next patch. In this patch, return -EOPNOTSUPP".
I think that it is a good idea. The final result should be the same.
Please send out the latest commit following the suggestions.
Thanks a lot for your contributions and efforts.
Best Regards,
Zhu Yanjun
>
> Thanks,
> Daisuke
>
>
>>
>> --G--
>>
>>>
>>> Thanks,
>>> Daisuke
>>>
>>>>
>>>>
>>>> Zhu Yanjun
>>>>
>>>>> The comment is inserted to show the reason, which is based on the
>>>>> description from 'man 3 ibv_advise_mr' as follows:
>>>>> ===
>>>>> An application may pre-fetch any address range within an ODP MR
>>>>> when using the IBV_ADVISE_MR_ADVICE_PREFETCH or
>>>>> IBV_ADVISE_MR_ADVICE_PREFETCH_WRITE advice. Semantically, this
>>>>> operation is best-effort. That means the kernel does not guarantee
>>>>> that underlying pages are updated in the HCA or the pre-fetched
>>>>> pages would remain resident.
>>>>> ===
>>>>>
>>>>> Thanks,
>>>>> Daisuke
>>>>>
>>>>>>
>>>>>> Zhu Yanjun
>>>>>>
>>>>>>> +
>>>>>>> + return 0;
>>>>>>> +}
>>>>>>> +
>>>>>>> +int rxe_ib_advise_mr(struct ib_pd *ibpd,
>>>>>>> + enum ib_uverbs_advise_mr_advice advice,
>>>>>>> + u32 flags,
>>>>>>> + struct ib_sge *sg_list,
>>>>>>> + u32 num_sge,
>>>>>>> + struct uverbs_attr_bundle *attrs)
>>>>>>> +{
>>>>>>> + if (advice != IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH &&
>>>>>>> + advice != IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_WRITE &&
>>>>>>> + advice != IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_NO_FAULT)
>>>>>>> + return -EOPNOTSUPP;
>>>>>>> +
>>>>>>> + return rxe_ib_advise_mr_prefetch(ibpd, advice, flags,
>>>>>>> + sg_list, num_sge);
>>>>>>> +}
>>>>>>
>>>>>
>>>
>>>
>
Powered by blists - more mailing lists