From: Simon Horman <horms@kernel•org>
To: Jijie Shao <shaojijie@huawei•com>
Cc: davem@davemloft•net, edumazet@google•com, kuba@kernel•org,
pabeni@redhat•com, andrew+netdev@lunn•ch, shenjian15@huawei•com,
liuyonglong@huawei•com, chenhao418@huawei•com,
jonathan.cameron@huawei•com,
shameerali.kolothum.thodi@huawei•com, salil.mehta@huawei•com,
netdev@vger•kernel.org, linux-kernel@vger•kernel.org
Subject: Re: [PATCH V2 net 4/4] net: hns3: default enable tx bounce buffer when smmu enabled
Date: Wed, 23 Jul 2025 08:29:00 +0100 [thread overview]
Message-ID: <20250723072900.GV2459@horms.kernel.org> (raw)
In-Reply-To: <20250722125423.1270673-5-shaojijie@huawei.com>
On Tue, Jul 22, 2025 at 08:54:23PM +0800, Jijie Shao wrote:
> The SMMU engine on HIP09 chip has a hardware issue.
> SMMU pagetable prefetch features may prefetch and use a invalid PTE
> even the PTE is valid at that time. This will cause the device trigger
> fake pagefaults. The solution is to avoid prefetching by adding a
> SYNC command when smmu mapping a iova. But the performance of nic has a
> sharp drop. Then we do this workaround, always enable tx bounce buffer,
> avoid mapping/unmapping on TX path.
>
> This issue only affects HNS3, so we always enable
> tx bounce buffer when smmu enabled to improve performance.
>
> Fixes: 295ba232a8c3 ("net: hns3: add device version to replace pci revision")
> Signed-off-by: Jian Shen <shenjian15@huawei•com>
> Signed-off-by: Jijie Shao <shaojijie@huawei•com>
> ---
> ChangeLog:
> v1 -> v2:
> - Split this patch, omits the ethtool changes,
> ethtool changes will be sent to net-next, suggested by Simon Horman
> v1: https://lore.kernel.org/all/20250702130901.2879031-1-shaojijie@huawei.com/
Thanks for breaking this out.
Reviewed-by: Simon Horman <horms@kernel•org>
next prev parent reply other threads:[~2025-07-23 7:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-22 12:54 [PATCH V2 net 0/4] There are some bugfix for the HNS3 ethernet driver Jijie Shao
2025-07-22 12:54 ` [PATCH V2 net 1/4] net: hns3: fix concurrent setting vlan filter issue Jijie Shao
2025-07-22 12:54 ` [PATCH V2 net 2/4] net: hns3: disable interrupt when ptp init failed Jijie Shao
2025-07-22 12:54 ` [PATCH V2 net 3/4] net: hns3: fixed vf get max channels bug Jijie Shao
2025-07-22 12:54 ` [PATCH V2 net 4/4] net: hns3: default enable tx bounce buffer when smmu enabled Jijie Shao
2025-07-23 7:29 ` Simon Horman [this message]
2025-07-24 9:29 ` [PATCH V2 net 0/4] There are some bugfix for the HNS3 ethernet driver Paolo Abeni
2025-07-24 9:40 ` patchwork-bot+netdevbpf
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