On Fri, Aug 16, 2024 at 02:53:31PM +0100, Will Deacon wrote: > 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(). OK. Let's go with your approach then: + if (arm_smmu_cmdq_needs_busy_polling(smmu, cmdq)) + u64p_replace_bits(cmd, CMDQ_SYNC_0_CS_NONE, CMDQ_SYNC_0_CS); Thanks Nicolin
