Messages in this thread | | | Date | Tue, 5 Sep 2023 22:05:04 -0700 | From | Easwar Hariharan <> | Subject | Re: [PATCH v2 1/1] iommu/arm-smmu-v3: Fix error case of range command |
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On 8/25/23 01:12, zhurui wrote: > On 2023/8/19 0:21, Will Deacon wrote: >> On Fri, Aug 18, 2023 at 05:19:31PM +0100, Robin Murphy wrote: >>> On 2023-08-09 14:48, Robin Murphy wrote: >>> [...] >>>> Does the patch below work for you? >>> >>> Any comments on this? Just noticed this commit on a local dev branch and >>> realised I'd totally forgotten about it already. I'm pretty confident it >>> ought to be right, but then it *was* also me who missed the original bug to >>> begin with... ;) >> >> I'm happy to take it if zhurui can confirm that it fixes their issue... >> >> Will (had also forgotten about this) >> >>>> ----->8----- >>>> Subject: [PATCH] iommu/arm-smmu-v3: Avoid constructing invalid range >>>> commands >>>> >>>> Although io-pgtable's non-leaf invalidations are always for full tables, >>>> I missed that SVA also uses non-leaf invalidations, while being at the >>>> mercy of whatever range the MMU notifier throws at it. This means it >>>> definitely wants the previous TTL fix as well, since it also doesn't >>>> know exactly which leaf level(s) may need invalidating, but it can also >>>> give us less-aligned ranges wherein certain corners may lead to building >>>> an invalid command where TTL, Num and Scale are all 0. It should be fine >>>> to handle this by over-invalidating an extra page, since falling back to >>>> a non-range command opens up a whole can of errata-flavoured worms. >>>> >>>> Fixes: 6833b8f2e199 ("iommu/arm-smmu-v3: Set TTL invalidation hint better") >>>> Reported-by: Rui Zhu <zhurui3@huawei.com> >>>> Signed-off-by: Robin Murphy <robin.murphy@arm.com> >>>> --- >>>> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 15 ++++++++++----- >>>> 1 file changed, 10 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> index 9b0dc3505601..6ccbae9b93a1 100644 >>>> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> @@ -1895,18 +1895,23 @@ static void __arm_smmu_tlb_inv_range(struct >>>> arm_smmu_cmdq_ent *cmd, >>>> /* Get the leaf page size */ >>>> tg = __ffs(smmu_domain->domain.pgsize_bitmap); >>>> >>>> + num_pages = size >> tg; >>>> + >>>> /* Convert page size of 12,14,16 (log2) to 1,2,3 */ >>>> cmd->tlbi.tg = (tg - 10) / 2; >>>> >>>> /* >>>> - * Determine what level the granule is at. For non-leaf, >>>> io-pgtable >>>> - * assumes .tlb_flush_walk can invalidate multiple levels at once, >>>> - * so ignore the nominal last-level granule and leave TTL=0. >>>> + * Determine what level the granule is at. For non-leaf, both >>>> + * io-pgtable and SVA pass a nominal last-level granule because >>>> + * they don't know what level(s) actually apply, so ignore that >>>> + * and leave TTL=0. However for various errata reasons we still >>>> + * want to use a range command, so avoid the SVA corner case >>>> + * where both scale and num could be 0 as well. >>>> */ >>>> if (cmd->tlbi.leaf) >>>> cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3)); >>>> - >>>> - num_pages = size >> tg; >>>> + else if ((num_pages & CMDQ_TLBI_RANGE_NUM_MAX) == 1) >>>> + num_pages++; >>>> } >>>> >>>> cmds.num = 0; >>>> > > Hi, Will and Robin, > Sorry for taking so long to reply you. We have some problems with our machine these days. It's > solved just today. I give a test with Robin's patch for our testcase, everything is ok. I think > the problem has been solved. > > Thanks, > ZhuRui. >
Hi Robin,
Could you please send out this patch since ZhuRui has confirmed it fixes their issue and CC it to stable for v5.15+? Or if Will is willing to pick it up off this thread, I can do the backport to stable.
-- Thanks, Easwar
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