On Fri, Sep 01, 2023 at 01:39:04PM -0700, Nicolin Chen wrote:
> 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.
>
> Fixes: 51d113c3be09 ("iommu/arm-smmu-v3: Make BTM optional for SVA")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 11 ++++++++---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 9 +++++++++
> 2 files changed, 17 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..7ec3f5219250 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
> @@ -201,9 +201,14 @@ static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn,
> */
> size = end - start;
>
> - 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);
> + if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_BTM)) {
> + if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_RANGE_INV) &&
> + size >= CMDQ_MAX_TLBI_OPS * PAGE_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);
cosmetic nit: Please use braces for the multi-line conditionals.
> + }
> arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, start, size);
> }
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> index dcab85698a4e..79a81eed1dcc 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -326,6 +326,15 @@
> */
> #define CMDQ_BATCH_ENTRIES BITS_PER_LONG
>
> +/*
> + * 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))
Maybe stick "SVA" in the name of this somewhere, since that's the reason why
looking at PAGE_SHIFT is relevant?
Will
