From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Will Deacon <will@kernel.org>
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
linux-pci@vger.kernel.org, sudeep.holla@arm.com,
rjw@rjwysocki.net, linux-acpi@vger.kernel.org,
iommu@lists.linux-foundation.org, robh+dt@kernel.org,
guohanjun@huawei.com, bhelgaas@google.com,
zhangfei.gao@linaro.org, robin.murphy@arm.com,
linux-arm-kernel@lists.infradead.org, lenb@kernel.org
Subject: Re: [PATCH v4 10/13] iommu/arm-smmu-v3: Add second level of context descriptor table
Date: Wed, 15 Jan 2020 10:45:27 +0100 [thread overview]
Message-ID: <20200115094527.GB32782@myrica> (raw)
In-Reply-To: <20200114150435.GA2579@willie-the-truck>
On Tue, Jan 14, 2020 at 03:04:36PM +0000, Will Deacon wrote:
> On Thu, Dec 19, 2019 at 05:30:30PM +0100, Jean-Philippe Brucker wrote:
> > The SMMU can support up to 20 bits of SSID. Add a second level of page
> > tables to accommodate this. Devices that support more than 1024 SSIDs now
> > have a table of 1024 L1 entries (8kB), pointing to tables of 1024 context
> > descriptors (64kB), allocated on demand.
> >
> > Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > ---
> > drivers/iommu/arm-smmu-v3.c | 154 +++++++++++++++++++++++++++++++++---
> > 1 file changed, 144 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> > index b825a5639afc..bf106a7b53eb 100644
> > --- a/drivers/iommu/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm-smmu-v3.c
> > @@ -224,6 +224,7 @@
> >
> > #define STRTAB_STE_0_S1FMT GENMASK_ULL(5, 4)
> > #define STRTAB_STE_0_S1FMT_LINEAR 0
> > +#define STRTAB_STE_0_S1FMT_64K_L2 2
> > #define STRTAB_STE_0_S1CTXPTR_MASK GENMASK_ULL(51, 6)
> > #define STRTAB_STE_0_S1CDMAX GENMASK_ULL(63, 59)
> >
> > @@ -263,7 +264,20 @@
> >
> > #define STRTAB_STE_3_S2TTB_MASK GENMASK_ULL(51, 4)
> >
> > -/* Context descriptor (stage-1 only) */
> > +/*
> > + * Context descriptors.
> > + *
> > + * Linear: when less than 1024 SSIDs are supported
> > + * 2lvl: at most 1024 L1 entries,
> > + * 1024 lazy entries per table.
> > + */
> > +#define CTXDESC_SPLIT 10
> > +#define CTXDESC_L2_ENTRIES (1 << CTXDESC_SPLIT)
> > +
> > +#define CTXDESC_L1_DESC_DWORDS 1
> > +#define CTXDESC_L1_DESC_VALID 1
>
> #define CTXDESC_L1_DESC_V (1UL << 0)
>
> fits better with the rest of the driver and also ensures that the thing
> is unsigned (we should probably switch over the BIT macros, but that's a
> separate cleanup patch).
>
> > +#define CTXDESC_L1_DESC_L2PTR_MASK GENMASK_ULL(51, 12)
> > +
> > #define CTXDESC_CD_DWORDS 8
> > #define CTXDESC_CD_0_TCR_T0SZ GENMASK_ULL(5, 0)
> > #define ARM64_TCR_T0SZ GENMASK_ULL(5, 0)
> > @@ -575,7 +589,12 @@ struct arm_smmu_cd_table {
> > };
> >
> > struct arm_smmu_s1_cfg {
> > - struct arm_smmu_cd_table table;
> > + /* Leaf tables or linear table */
> > + struct arm_smmu_cd_table *tables;
> > + size_t num_tables;
> > + /* First level tables, when two levels are used */
> > + __le64 *l1ptr;
> > + dma_addr_t l1ptr_dma;
>
> It probably feels like a nit, but I think this is all a little hard to read
> because it differs unnecessarily from the way the stream table is handled.
>
> Could we align the two as follows? (I've commented things with what they
> refer to in your patch):
>
>
> struct arm_smmu_l1_ctx_desc { // arm_smmu_cd_table
> __le64 *l2ptr; // ptr
> dma_addr_t l2ptr_dma; // ptr_dma
> };
>
> struct arm_smmu_ctx_desc_cfg {
> __le64 *cdtab; // l1ptr
> dma_addr_t cdtab_dma; // l1ptr_dma
> struct arm_smmu_l1_ctx_desc *l1_desc; // tables
> unsigned int num_l1_ents; // num_tables
> };
>
> struct arm_smmu_s1_cfg {
> struct arm_smmu_ctx_desc_cfg cdcfg;
> struct arm_smmu_ctx_desc cd;
> u8 s1fmt;
> u8 s1cdmax;
> };
>
>
> I don't know whether you'd then want to move s1fmt and s1cdmax into the
> cdcfg, I'll leave that up to you. Similarly if you want any functions
> to operate on arm_smmu_ctx_desc_cfg in preference to arm_smmu_s1_cfg.
>
> Thoughts?
No problem, it looks cleaner overall.
Thanks,
Jean
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next prev parent reply other threads:[~2020-01-15 9:45 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-19 16:30 [PATCH v4 00/13] iommu: Add PASID support to Arm SMMUv3 Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 01/13] iommu/arm-smmu-v3: Drop __GFP_ZERO flag from DMA allocation Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 02/13] dt-bindings: document PASID property for IOMMU masters Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 03/13] iommu/arm-smmu-v3: Parse PASID devicetree property of platform devices Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 04/13] ACPI/IORT: Parse SSID property of named component node Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 05/13] iommu/arm-smmu-v3: Prepare arm_smmu_s1_cfg for SSID support Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 06/13] iommu/arm-smmu-v3: Add context descriptor tables allocators Jean-Philippe Brucker
2020-01-14 11:06 ` Will Deacon
2020-01-14 11:52 ` Jean-Philippe Brucker
2020-01-14 11:56 ` Will Deacon
2019-12-19 16:30 ` [PATCH v4 07/13] iommu/arm-smmu-v3: Add support for Substream IDs Jean-Philippe Brucker
2020-01-14 12:38 ` Will Deacon
2020-01-14 16:30 ` Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 08/13] iommu/arm-smmu-v3: Propagate ssid_bits Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 09/13] iommu/arm-smmu-v3: Prepare for handling arm_smmu_write_ctx_desc() failure Jean-Philippe Brucker
2020-01-14 12:42 ` Will Deacon
2020-01-14 16:31 ` Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 10/13] iommu/arm-smmu-v3: Add second level of context descriptor table Jean-Philippe Brucker
2019-12-20 7:37 ` Auger Eric
2020-01-14 15:04 ` Will Deacon
2020-01-15 9:45 ` Jean-Philippe Brucker [this message]
2019-12-19 16:30 ` [PATCH v4 11/13] iommu/arm-smmu-v3: Improve add_device() error handling Jean-Philippe Brucker
2020-01-14 15:25 ` Will Deacon
2020-01-15 16:17 ` Will Deacon
2020-01-15 17:44 ` Robin Murphy
2019-12-19 16:30 ` [PATCH v4 12/13] PCI/ATS: Add PASID stubs Jean-Philippe Brucker
2019-12-19 16:30 ` [PATCH v4 13/13] iommu/arm-smmu-v3: Add support for PCI PASID Jean-Philippe Brucker
2019-12-20 7:37 ` Auger Eric
2020-01-14 12:45 ` Will Deacon
2020-01-15 7:57 ` Jean-Philippe Brucker
2020-01-09 14:36 ` [PATCH v4 00/13] iommu: Add PASID support to Arm SMMUv3 Jean-Philippe Brucker
2020-01-09 14:41 ` Will Deacon
2020-01-10 7:15 ` Jean-Philippe Brucker
2020-01-14 15:40 ` Will Deacon
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