From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: will@kernel.org, robin.murphy@arm.com, joro@8bytes.org,
thierry.reding@gmail.com, vdumpa@nvidia.com,
jonathanh@nvidia.com, linux-kernel@vger.kernel.org,
iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
linux-tegra@vger.kernel.org
Subject: Re: [PATCH v6 5/6] iommu/arm-smmu-v3: Add in-kernel support for NVIDIA Tegra241 (Grace) CMDQV
Date: Thu, 2 May 2024 09:41:03 -0300 [thread overview]
Message-ID: <20240502124103.GA3341011@nvidia.com> (raw)
In-Reply-To: <ZjJ/S1bawYkfs1I4@Asurada-Nvidia>
On Wed, May 01, 2024 at 10:43:39AM -0700, Nicolin Chen wrote:
> > It doesn't fix any real race, I'm not sure what this is supposed to be
> > doing. The cmdq becomes broken and you get an ISR, so before the ISR
> > it will still post but get stuck, during the ISR it will avoid
> > posting, and after it will go back to posting?
> >
> > Why? Just always post to the Q and let the ISR fix it?
>
> Yes, we could do so. I was thinking of the worst case by giving
> the guest OS a chance to continue (though in a slower mode), if
> something unrecoverable happens to the VINTF/VCMDQ part.
Does that happn? The stuck vcmdq will have stuck entries on it no
matter what, can we actually fully recover from that? Ie re-issue the
commands on another queue?
> > So just don't use it. There is no value if the places where it should
> > work automatically are not functioning.
>
> I thought devm could work when rmmod too, not only when the probe
> fails..
It is limited to cases when the probing driver of the passed struct
device unbinds, including probe failure.
Jason
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next prev parent reply other threads:[~2024-05-02 12:41 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-30 4:43 [PATCH v6 0/6] Add Tegra241 (Grace) CMDQV Support (part 1/2) Nicolin Chen
2024-04-30 4:43 ` [PATCH v6 1/6] iommu/arm-smmu-v3: Pass in cmdq pointer to arm_smmu_cmdq_issue_cmdlist() Nicolin Chen
2024-04-30 13:54 ` Jason Gunthorpe
2024-04-30 4:43 ` [PATCH v6 2/6] iommu/arm-smmu-v3: Add CS_NONE quirk Nicolin Chen
2024-04-30 14:22 ` Jason Gunthorpe
2024-04-30 16:30 ` Nicolin Chen
2024-04-30 16:37 ` Jason Gunthorpe
2024-04-30 16:43 ` Nicolin Chen
2024-04-30 4:43 ` [PATCH v6 3/6] iommu/arm-smmu-v3: Make arm_smmu_cmdq_init reusable Nicolin Chen
2024-04-30 14:24 ` Jason Gunthorpe
2024-04-30 15:50 ` Nicolin Chen
2024-04-30 4:43 ` [PATCH v6 4/6] iommu/arm-smmu-v3: Make __arm_smmu_cmdq_skip_err reusable Nicolin Chen
2024-04-30 14:06 ` Jason Gunthorpe
2024-04-30 15:48 ` Nicolin Chen
2024-04-30 4:43 ` [PATCH v6 5/6] iommu/arm-smmu-v3: Add in-kernel support for NVIDIA Tegra241 (Grace) CMDQV Nicolin Chen
2024-04-30 16:35 ` Jason Gunthorpe
2024-04-30 18:08 ` Nicolin Chen
2024-05-01 13:00 ` Jason Gunthorpe
2024-05-01 17:43 ` Nicolin Chen
2024-05-02 12:41 ` Jason Gunthorpe [this message]
2024-05-02 19:26 ` Nicolin Chen
2024-04-30 4:43 ` [PATCH v6 6/6] iommu/tegra241-cmdqv: Limit CMDs for guest owned VINTF Nicolin Chen
2024-04-30 17:06 ` Jason Gunthorpe
2024-04-30 18:58 ` Nicolin Chen
2024-05-01 0:17 ` Jason Gunthorpe
2024-05-01 16:32 ` Nicolin Chen
2024-05-06 3:52 ` Nicolin Chen
2024-05-06 13:00 ` Jason Gunthorpe
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