Messages in this thread | | | Date | Fri, 4 Aug 2023 11:30:03 -0700 | From | Nicolin Chen <> | Subject | Re: [PATCH v2 1/1] iommu/arm-smmu-v3: Fix error case of range command |
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On Fri, Aug 04, 2023 at 05:52:25PM +0100, Will Deacon wrote: > On Fri, Aug 04, 2023 at 05:31:20PM +0800, zhurui wrote: > > When tg != 0 but ttl, scale, num all 0 in a range tlbi command, it > > is reserved and will cause the CERROR_ILL error. This case means > > that the size to be invalidated is only one page size, and the > > range invalidation is meaningless here. So we set tg to 0 in this > > case to do an non-range invalidation instead.
> > @@ -1930,6 +1927,12 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd, > > num = (num_pages >> scale) & CMDQ_TLBI_RANGE_NUM_MAX; > > cmd->tlbi.num = num - 1; > > > > + /* Prevent error caused by one page tlbi with leaf 0 */ > > + if (scale == 0 && num == 1 && cmd->tlbi.leaf == 0) > > + cmd->tlbi.tg = 0; > > This should only be true for the last iteration, right (i.e. when num_pages > == 1)? In which case, I'd prefer to leave the old code as-is and just add: > > /* Single-page leaf invalidation requires a TG field of 0 */ > if (num_pages == 1 && !cmd->tlbi.leaf) > cmd->tlbi.tg = 0;
Is "!cmd->tlbi.leaf" to be "leaf" or "non-leaf"?
IIUIC, this "num_pages == 1" implies "NUM == 0, SCALE == 0" while the "!cmd->tlbi.leaf" implies "TTL = 0b00", which in combination would result in a CERROR_ILL mentioned by the spec?
I feel this could be more clear by just checking the three fields following the spec...
Thanks Nicolin
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