[PATCH v11 2/9] iommu/arm-smmu-v3: Enforce arm_smmu_cmdq_build_sync_cmd
Will Deacon
will at kernel.org
Fri Aug 16 06:53:31 PDT 2024
On Tue, Aug 06, 2024 at 07:11:47PM -0700, Nicolin Chen wrote:
> There is an existing arm_smmu_cmdq_build_sync_cmd() so the driver should
> call it at all places other than going through arm_smmu_cmdq_build_cmd()
> separately. This helps the following patch that adds a CS_NONE option.
>
> Note that this changes the type of CMD_SYNC in __arm_smmu_cmdq_skip_err,
> in ARM_SMMU_OPT_MSIPOLL=true case, from previously a non-MSI one to now
> an MSI one that is proven to still work using a hacking test:
> nvme: Adding to iommu group 10
> nvme: --------hacking-----------
> arm-smmu-v3: unexpected global error reported (0x00000001),
> this could be serious
> arm-smmu-v3: CMDQ error (cons 0x01000022): Illegal command
> arm-smmu-v3: skipping command in error state:
> arm-smmu-v3: 0x0000000000000000
> arm-smmu-v3: 0x0000000000000000
> nvme: -------recovered----------
> nvme nvme0: 72/0/0 default/read/poll queues
> nvme0n1: p1 p2
Hmm, I'm still a little wary of this. The only reason we emit a CMD_SYNC
in __arm_smmu_cmdq_skip_err() is because the SMMU doesn't have a NOP
command. So I'd really like the SYNC to have as little functionality
as possible in this case.
I think we could either propapate the 'cs' field down to
arm_smmu_cmdq_build_cmd() or just open-code the command-creation in
__arm_smmu_cmdq_skip_err().
Will
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