Messages in this thread | | | Date | Tue, 1 Aug 2023 09:55:05 +0100 | From | Will Deacon <> | Subject | Re: [PATCH 1/1] Revert "iommu/arm-smmu-v3: Set TTL invalidation hint better" |
| |
On Mon, Jul 31, 2023 at 02:21:22PM +0800, wangwudi wrote: > From: Rui Zhu <zhurui3@huawei.com> > > This reverts commit 6833b8f2e19945a41e4d5efd8c6d9f4cae9a5b7d. > > This constraint violates the protocol. When tg is not 0 but ttl, scale, > and num are 0, the hardware reports the CERROR_IL gerror. In the > protocol, leaf is not a prerequisite for TTL. > > Cc: Will Deacon <will@kernel.org> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Lu Baolu <baolu.lu@linux.intel.com> > Cc: Jason Gunthorpe <jgg@ziepe.ca> > Cc: Yicong Yang <yangyicong@hisilicon.com> > Cc: Tomas Krcka <krckatom@amazon.de> > Cc: Jean-Philippe Brucker <jean-philippe@linaro.org> > Cc: Nicolin Chen <nicolinc@nvidia.com> > Cc: Rui Zhu <zhurui3@huawei.com> > > Signed-off-by: Rui Zhu <zhurui3@huawei.com> > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 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..098e84cfa82f 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > @@ -1898,13 +1898,8 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd, > /* 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. > - */ > - if (cmd->tlbi.leaf) > - cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3)); > + /* Determine what level the granule is at */ > + cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
Doesn't this reintroduce the bug that 6833b8f2e199 tried to fix?
afaict, we should only hit the problematic case of tg != 0 but ttl, scale and num all 0 if we're invalidating a single page, so shouldn't we just zap tg in that case, since it's not doing anything useful?
I hesitate to say we should avoid range invalidation altogether for single-page invalidations because I think some errata workarounds might need that to work.
Will
| |