Re: [PATCH v1 13/14] iommu/arm-smmu-v3: Add CMDQ_OP_TLBI_NH_VAA and CMDQ_OP_TLBI_NH_ALL

Robin Murphy
2023-03-09T13:45:43Z

On 2023-03-09 10:53, Nicolin Chen wrote:
> With a nested translation setup, a stage-1 Context Descriptor table can be
> managed by a guest OS in the user space. So, the kernel driver should not
> assume that the guest OS will use a user space device driver that doesn't
> support TLBI_NH_VAA and TLBI_NH_ALL commands.
>
> Add them in the arm_smmu_cmdq_build_cmd(), to prepare for support of these
> two TLBI invalidation requests from the guest level.
>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 ++++
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 2 ++
> 2 files changed, 6 insertions(+)
>
> 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 1f318b5e0921..ac63185ae268 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -277,6 +277,9 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
> /* Cover the entire SID range */
> cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_RANGE, 31);
> break;
> + case CMDQ_OP_TLBI_NH_VAA:
> + ent->tlbi.asid = 0;

This is backwards - NH_VA is a superset of NH_VAA (not to mention that
quietly modifying the input argument is ugly; in fact it might be nice
if ent was const here).

Please follow the existing pattern, and decouple NH_VA from EL2_VA if
necessary.

Thanks,
Robin.

> + fallthrough;
> case CMDQ_OP_TLBI_NH_VA:
> cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
> fallthrough;
> @@ -301,6 +304,7 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
> case CMDQ_OP_TLBI_NH_ASID:
> cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
> fallthrough;
> + case CMDQ_OP_TLBI_NH_ALL:
> case CMDQ_OP_TLBI_S12_VMALL:
> cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
> break;
> 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 6cf516852721..6181d6cd8b51 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -454,8 +454,10 @@ struct arm_smmu_cmdq_ent {
> };
> } cfgi;
>
> + #define CMDQ_OP_TLBI_NH_ALL 0x10
> #define CMDQ_OP_TLBI_NH_ASID 0x11
> #define CMDQ_OP_TLBI_NH_VA 0x12
> + #define CMDQ_OP_TLBI_NH_VAA 0x13
> #define CMDQ_OP_TLBI_EL2_ALL 0x20
> #define CMDQ_OP_TLBI_EL2_ASID 0x21
> #define CMDQ_OP_TLBI_EL2_VA 0x22