commit d5afb4b47e13161b3f33904d45110f9e6463bad6 upstream.

When running an SVA case, the following soft lockup is triggered: -------------------------------------------------------------------- watchdog: BUG: soft lockup - CPU#244 stuck for 26s! pstate: 83400009 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : arm_smmu_cmdq_issue_cmdlist+0x178/0xa50 lr : arm_smmu_cmdq_issue_cmdlist+0x150/0xa50 sp : ffff8000d83ef290 x29: ffff8000d83ef290 x28: 000000003b9aca00 x27: 0000000000000000 x26: ffff8000d83ef3c0 x25: da86c0812194a0e8 x24: 0000000000000000 x23: 0000000000000040 x22: ffff8000d83ef340 x21: ffff0000c63980c0 x20: 0000000000000001 x19: ffff0000c6398080 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: ffff3000b4a3bbb0 x14: ffff3000b4a30888 x13: ffff3000b4a3cf60 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : ffffc08120e4d6bc x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000048cfa x5 : 0000000000000000 x4 : 0000000000000001 x3 : 000000000000000a x2 : 0000000080000000 x1 : 0000000000000000 x0 : 0000000000000001 Call trace: arm_smmu_cmdq_issue_cmdlist+0x178/0xa50 __arm_smmu_tlb_inv_range+0x118/0x254 arm_smmu_tlb_inv_range_asid+0x6c/0x130 arm_smmu_mm_invalidate_range+0xa0/0xa4 __mmu_notifier_invalidate_range_end+0x88/0x120 unmap_vmas+0x194/0x1e0 unmap_region+0xb4/0x144 do_mas_align_munmap+0x290/0x490 do_mas_munmap+0xbc/0x124 __vm_munmap+0xa8/0x19c __arm64_sys_munmap+0x28/0x50 invoke_syscall+0x78/0x11c el0_svc_common.constprop.0+0x58/0x1c0 do_el0_svc+0x34/0x60 el0_svc+0x2c/0xd4 el0t_64_sync_handler+0x114/0x140 el0t_64_sync+0x1a4/0x1a8 --------------------------------------------------------------------

The commit 06ff87bae8d3 ("arm64: mm: remove unused functions and variable protoypes") fixed a similar lockup on the CPU MMU side. Yet, it can occur to SMMU too since arm_smmu_mm_invalidate_range() is typically called next to MMU tlb flush function, e.g. tlb_flush_mmu_tlbonly { tlb_flush { __flush_tlb_range { // check MAX_TLBI_OPS } } mmu_notifier_invalidate_range { arm_smmu_mm_invalidate_range { // does not check MAX_TLBI_OPS } } }

Clone a CMDQ_MAX_TLBI_OPS from the MAX_TLBI_OPS in tlbflush.h, since in an SVA case SMMU uses the CPU page table, so it makes sense to align with the tlbflush code. Then, replace per-page TLBI commands with a single per-asid TLBI command, if the request size hits this threshold.

Signed-off-by: Nicolin Chen nicolinc@nvidia.com Link: https://lore.kernel.org/r/20230920052257.8615-1-nicolinc@nvidia.com Signed-off-by: Will Deacon will@kernel.org --- .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 27 ++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c index a5a63b1c947e..98d3ba7f9487 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c @@ -186,6 +186,15 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd) } }

+/* + * Cloned from the MAX_TLBI_OPS in arch/arm64/include/asm/tlbflush.h, this + * is used as a threshold to replace per-page TLBI commands to issue in the + * command queue with an address-space TLBI command, when SMMU w/o a range + * invalidation feature handles too many per-page TLBI commands, which will + * otherwise result in a soft lockup. + */ +#define CMDQ_MAX_TLBI_OPS (1 << (PAGE_SHIFT - 3)) + static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn, struct mm_struct *mm, unsigned long start, unsigned long end) @@ -200,10 +209,22 @@ static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn, * range. So do a simple translation here by calculating size correctly. */ size = end - start; + if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_RANGE_INV)) { + if (size >= CMDQ_MAX_TLBI_OPS * PAGE_SIZE) + size = 0; + } + + if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_BTM)) { + if (!size) + arm_smmu_tlb_inv_asid(smmu_domain->smmu, + smmu_mn->cd->asid); + else + arm_smmu_tlb_inv_range_asid(start, size, + smmu_mn->cd->asid, + PAGE_SIZE, false, + smmu_domain); + }

- if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_BTM)) - arm_smmu_tlb_inv_range_asid(start, size, smmu_mn->cd->asid, - PAGE_SIZE, false, smmu_domain); arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, start, size); }