Re: [PATCH v14 06/13] iommu/smmuv3: Allow stage 1 invalidation with unmanaged ASIDs

[Kunkun Jiang]

Hi Eric,

On 2021/2/24 4:56, Eric Auger wrote:
> With nested stage support, soon we will need to invalidate
> S1 contexts and ranges tagged with an unmanaged asid, this
> latter being managed by the guest. So let's introduce 2 helpers
> that allow to invalidate with externally managed ASIDs
>
> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>
> ---
>
> v13 -> v14
> - Actually send the NH_ASID command (reported by Xingang Wang)
> ---
>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 38 ++++++++++++++++-----
>   1 file changed, 29 insertions(+), 9 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 5579ec4fccc8..4c19a1114de4 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -1843,9 +1843,9 @@ int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
>   }
>   
>   /* IO_PGTABLE API */
> -static void arm_smmu_tlb_inv_context(void *cookie)
> +static void __arm_smmu_tlb_inv_context(struct arm_smmu_domain *smmu_domain,
> +				       int ext_asid)
>   {
> -	struct arm_smmu_domain *smmu_domain = cookie;
>   	struct arm_smmu_device *smmu = smmu_domain->smmu;
>   	struct arm_smmu_cmdq_ent cmd;
>   
> @@ -1856,7 +1856,13 @@ static void arm_smmu_tlb_inv_context(void *cookie)
>   	 * insertion to guarantee those are observed before the TLBI. Do be
>   	 * careful, 007.
>   	 */
> -	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> +	if (ext_asid >= 0) { /* guest stage 1 invalidation */
> +		cmd.opcode	= CMDQ_OP_TLBI_NH_ASID;
> +		cmd.tlbi.asid	= ext_asid;
> +		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
> +		arm_smmu_cmdq_issue_cmd(smmu, &cmd);
> +		arm_smmu_cmdq_issue_sync(smmu);
> +	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
>   		arm_smmu_tlb_inv_asid(smmu, smmu_domain->s1_cfg.cd.asid);
>   	} else {
>   		cmd.opcode	= CMDQ_OP_TLBI_S12_VMALL;
> @@ -1867,6 +1873,13 @@ static void arm_smmu_tlb_inv_context(void *cookie)
>   	arm_smmu_atc_inv_domain(smmu_domain, 0, 0, 0);
>   }
>   
> +static void arm_smmu_tlb_inv_context(void *cookie)
> +{
> +	struct arm_smmu_domain *smmu_domain = cookie;
> +
> +	__arm_smmu_tlb_inv_context(smmu_domain, -1);
> +}
> +
>   static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
>   				     unsigned long iova, size_t size,
>   				     size_t granule,
> @@ -1926,9 +1939,10 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
>   	arm_smmu_cmdq_batch_submit(smmu, &cmds);
>   }
>   
Here is the part of code in __arm_smmu_tlb_inv_range():
>         if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
>                 /* Get the leaf page size */
>                 tg = __ffs(smmu_domain->domain.pgsize_bitmap);
>
>                 /* 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 */
>                 cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
>
>                 num_pages = size >> tg;
>         }
When pSMMU supports RIL, we get the leaf page size by __ffs(smmu_domain->
domain.pgsize_bitmap). In nested mode, it is determined by host 
PAGE_SIZE. If
the host kernel and guest kernel has different translation granule (e.g. 
host 16K,
guest 4K), __arm_smmu_tlb_inv_range() will issue an incorrect tlbi command.

Do you have any idea about this issue?

Best Regards,
Kunkun Jiang
> -static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
> -					  size_t granule, bool leaf,
> -					  struct arm_smmu_domain *smmu_domain)
> +static void
> +arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
> +			      size_t granule, bool leaf, int ext_asid,
> +			      struct arm_smmu_domain *smmu_domain)
>   {
>   	struct arm_smmu_cmdq_ent cmd = {
>   		.tlbi = {
> @@ -1936,7 +1950,12 @@ static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
>   		},
>   	};
>   
> -	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> +	if (ext_asid >= 0) {  /* guest stage 1 invalidation */
> +		cmd.opcode	= smmu_domain->smmu->features & ARM_SMMU_FEAT_E2H ?
> +				  CMDQ_OP_TLBI_EL2_VA : CMDQ_OP_TLBI_NH_VA;
> +		cmd.tlbi.asid	= ext_asid;
> +		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
> +	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
>   		cmd.opcode	= smmu_domain->smmu->features & ARM_SMMU_FEAT_E2H ?
>   				  CMDQ_OP_TLBI_EL2_VA : CMDQ_OP_TLBI_NH_VA;
>   		cmd.tlbi.asid	= smmu_domain->s1_cfg.cd.asid;
> @@ -1944,6 +1963,7 @@ static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
>   		cmd.opcode	= CMDQ_OP_TLBI_S2_IPA;
>   		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
>   	}
> +
>   	__arm_smmu_tlb_inv_range(&cmd, iova, size, granule, smmu_domain);
>   
>   	/*
> @@ -1982,7 +2002,7 @@ static void arm_smmu_tlb_inv_page_nosync(struct iommu_iotlb_gather *gather,
>   static void arm_smmu_tlb_inv_walk(unsigned long iova, size_t size,
>   				  size_t granule, void *cookie)
>   {
> -	arm_smmu_tlb_inv_range_domain(iova, size, granule, false, cookie);
> +	arm_smmu_tlb_inv_range_domain(iova, size, granule, false, -1, cookie);
>   }
>   
>   static const struct iommu_flush_ops arm_smmu_flush_ops = {
> @@ -2523,7 +2543,7 @@ static void arm_smmu_iotlb_sync(struct iommu_domain *domain,
>   
>   	arm_smmu_tlb_inv_range_domain(gather->start,
>   				      gather->end - gather->start + 1,
> -				      gather->pgsize, true, smmu_domain);
> +				      gather->pgsize, true, -1, smmu_domain);
>   }
>   
>   static phys_addr_t