Messages in this thread | | | Date | Fri, 28 Jun 2019 10:52:51 +0100 | From | Will Deacon <> | Subject | Re: [PATCH] iommu/arm-smmu-v3: Fix incorrect fields being passed to prefetch command |
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On Fri, Jun 28, 2019 at 02:39:53PM +0530, Pratyush Yadav wrote: > According to the SMMUv3 spec [0] section 4.2.1, command 0x1 > (CMD_PREFETCH_CONFIG) does not take address and size as parameters. It > only takes StreamID, SSec, SubstreamID, and SSV. Address and Size are > parameters for command 0x2 (CMD_PREFETCH_ADDR). > > Tested on kernel 4.19 on TI J721E SOC. > > [0] https://static.docs.arm.com/ihi0070/a/IHI_0070A_SMMUv3.pdf > > Signed-off-by: Pratyush Yadav <p-yadav1@ti.com> > --- > drivers/iommu/arm-smmu-v3.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index 4d5a694f02c2..2d4dfd909436 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -413,6 +413,7 @@ struct arm_smmu_cmdq_ent { > /* Command-specific fields */ > union { > #define CMDQ_OP_PREFETCH_CFG 0x1 > + #define CMDQ_OP_PREFETCH_ADDR 0x2 > struct { > u32 sid; > u8 size; > @@ -805,10 +806,12 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent) > case CMDQ_OP_TLBI_EL2_ALL: > case CMDQ_OP_TLBI_NSNH_ALL: > break; > - case CMDQ_OP_PREFETCH_CFG: > - cmd[0] |= FIELD_PREP(CMDQ_PREFETCH_0_SID, ent->prefetch.sid); > + case CMDQ_OP_PREFETCH_ADDR: > cmd[1] |= FIELD_PREP(CMDQ_PREFETCH_1_SIZE, ent->prefetch.size); > cmd[1] |= ent->prefetch.addr & CMDQ_PREFETCH_1_ADDR_MASK; > + /* Fallthrough */ > + case CMDQ_OP_PREFETCH_CFG: > + cmd[0] |= FIELD_PREP(CMDQ_PREFETCH_0_SID, ent->prefetch.sid);
Hmm, but there's no issue here because the onus is on the caller not to initialise size and addr if they are using PREFETCH_CFG (and this is currently the case). Are you seeing a problem in practice?
I'm happy to take a patch adding support for PREFETCH_ADDR, but we'd need a caller first.
Also -- fancy sending me a board? ;)
Will
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