From: Andrew Rybchenko <email@example.com> To: Thomas Monjalon <firstname.lastname@example.org>, Ferruh Yigit <email@example.com> Cc: 方统浩50450 <firstname.lastname@example.org>, <email@example.com>, <firstname.lastname@example.org>, <email@example.com>, <firstname.lastname@example.org>, <email@example.com>, <firstname.lastname@example.org>, Jerin Jacob Kollanukkaran <email@example.com> Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH v2] Fixes: ethdev: secondary process change shared memory Date: Thu, 16 Jan 2020 10:43:42 +0300 Message-ID: <firstname.lastname@example.org> (raw) In-Reply-To: <3055448.clyjiGRsXx@xps> On 1/15/20 11:43 PM, Thomas Monjalon wrote: > 15/01/2020 19:35, Ferruh Yigit: >> On 1/15/2020 6:49 AM, 方统浩50450 wrote: >>> Hi Ferruh, thanks for your message. >>> >>> >>> We developed a ethtool-dpdk which is secondary process based dpdk 17.08 version. Our device >>> support hotplug detach, but hotplug deatch is failed when we use ethtool-dpdk.We found the >>> secondary process will change the shared memory when initializing.Secondary process calls >>> "rte_eth_dev_pci_allocate" function and enters "rte_eth_copy_pci_info" function. >>> (rte_eth_dev_pci_generic_probe -> rte_eth_dev_pci_allocate -> rte_eth_copy_pci_info) >>> Then it sets the value of struct "rte_eth_dev_data.dev_flags" to zero.In our platform, this value >>> is equal to 0x0003.(RTE_ETH_DEV_DETACHABLE | RTE_ETH_DEV_INTR_LSC),but after reset >>> the "dev_flags", the value changed to 0x0002.(RTE_ETH_DEV_DETACHABLE).So, our device hotplug >>> detach is failed.I found the similar problem in other dpdk version, include dpdk 19.11.Even though >>> the deivce hotplug detach is discarded,but i think the shared memory changed is unexpected by primary >>> process. Hold on, just for my understanding. As far as I can see RTE_ETH_DEV_DETACHABLE was removed in 17.11. Does it change something in above description? >> I agree this is the problem. >> In the driver code, 'rte_eth_copy_pci_info' is called only by primary process, >> >> but the generic code is faulty. >> >> And in 19.11 additionally 'eth_dev_pci_specific_init' also seems has same problem. Yes, as I understand RTE_ETH_DEV_CLOSE_REMOVE, RTE_ETH_DEV_BONDED_SLAVE, RTE_ETH_DEV_REPRESENTOR and RTE_ETH_DEV_NOLIVE_MAC_ADDR may be lost because of reinit (if not restored in other branches). Bad anyway. >>> Our driver is ixgbe, i think this problem has a little relationship with driver, Secondary process >>> enters "rte_eth_copy_pci_info" by "rte_eth_dev_pci_allocate".And I agree your opinion, the helper >>> function should simple on what it does.I have two ways to fix this problem, one is add an if-statement >>> >>> in "rte_eth_dev_pci_allocate" function to forbid secondary process enters "rte_eth_copy_pci_info" function, >>> another way is add an if-statement in "rte_eth_copy_pci_info" function to forbid secondary process change >>> shared memory.And First way need to ensure the "rte_eth_copy_pci_info" function won't be called anywhere else. >>> I think the second way is simple and lower risk. >> >> Yes these are the two options. >> >> I agree adding check in the 'rte_eth_copy_pci_info' covers all cases and safer. >> BUT my concern was adding decision making to simple/leaf function and make it >> harder to debug/use, instead of giving what primary/secondary process should >> call decision in higher level. >> >> But I just recognized that some PMDs are calling 'rte_eth_copy_pci_info' on >> secondary process, like mlx4 or szedata2, and most probably this is not their >> intention. >> And 'eth_dev->intr_handle' set in 'rte_eth_copy_pci_info', not calling this >> function may have side affect of 'eth_dev->intr_handle' not set in secondary. >> >> With above considerations I am OK to your proposal to cover all cases, Thomas, >> Andrew, any concern? I would put if condition in rte_eth_copy_pci_info(). It is the function which writes shared space from secondary process when it should not be done and it should be fixed there. > Do you mean drivers need to be fixed? I'm not sure that I fully understand it. Since copy function cares about intr_handle copying I'm afraid that it is not 100% correct to skip it in secondary process completely as many drivers do right now. Basically it makes eth_dev structure in secondary process inconsistent. However, it looks like most of these drivers simply obtain handle from pci_dev directly and it explains why they are not affected. There are exceptions which are potentially bugs, e.g. drivers/net/ice/ice_ethdev.c: ice_interrupt_handler at the end. I think that it would be better if intr_handle is always correct in eth_dev (both primary and secondary cases) and drivers use it instead of the same from pci_dev.
next prev parent reply other threads:[~2020-01-16 7:44 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-09 12:27 [dpdk-stable] [PATCH] ethdev: fix secondary process change share memory Fang TongHao 2020-01-10 7:30 ` Jeff Guo 2020-01-10 7:53 ` 方统浩50450 2020-01-13 5:03 ` [dpdk-stable] [PATCH v2] Fixes: ethdev: secondary process change shared memory Fang TongHao 2020-01-14 14:45 ` [dpdk-stable] [dpdk-dev] " Ferruh Yigit 2020-01-15 6:49 ` 方统浩50450 2020-01-15 18:35 ` Ferruh Yigit 2020-01-15 20:43 ` Thomas Monjalon 2020-01-16 7:43 ` Andrew Rybchenko [this message] 2020-01-16 9:04 ` Ferruh Yigit 2020-01-16 11:35 ` 方统浩50450 2020-01-16 12:18 ` Ferruh Yigit 2020-01-17 2:11 ` 方统浩50450 2020-01-16 9:00 ` Ferruh Yigit 2020-01-17 2:08 ` [dpdk-stable] [PATCH v3] " Fang TongHao 2020-01-17 8:33 ` Andrew Rybchenko 2020-01-17 17:58 ` [dpdk-stable] [dpdk-dev] " Ferruh Yigit
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