Re: [PATCH] iommu: PGTABLE_LPAE is also for RISCV

[Randy Dunlap]

Hi all,

On 3/30/23 00:31, Geert Uytterhoeven wrote:
> Hi Conor,
> 
> On Thu, Mar 30, 2023 at 8:25 AM Conor Dooley <conor.dooley@xxxxxxxxxxxxx> wrote:
>> On Wed, Mar 29, 2023 at 11:01:05PM -0700, Randy Dunlap wrote:
>>> On riscv64, linux-next-20233030 (and for several days earlier),
>>> there is a kconfig warning:
>>>
>>> WARNING: unmet direct dependencies detected for IOMMU_IO_PGTABLE_LPAE
>>>   Depends on [n]: IOMMU_SUPPORT [=y] && (ARM || ARM64 || COMPILE_TEST [=n]) && !GENERIC_ATOMIC64 [=n]
>>>   Selected by [y]:
>>>   - IPMMU_VMSA [=y] && IOMMU_SUPPORT [=y] && (ARCH_RENESAS [=y] || COMPILE_TEST [=n]) && !GENERIC_ATOMIC64 [=n]
>>>
>>> and build errors:
>>>
>>> riscv64-linux-ld: drivers/iommu/io-pgtable-arm.o: in function `.L140':
>>> io-pgtable-arm.c:(.init.text+0x1e8): undefined reference to `alloc_io_pgtable_ops'
>>> riscv64-linux-ld: drivers/iommu/io-pgtable-arm.o: in function `.L168':
>>> io-pgtable-arm.c:(.init.text+0xab0): undefined reference to `free_io_pgtable_ops'
>>> riscv64-linux-ld: drivers/iommu/ipmmu-vmsa.o: in function `.L140':
>>> ipmmu-vmsa.c:(.text+0xbc4): undefined reference to `free_io_pgtable_ops'
>>> riscv64-linux-ld: drivers/iommu/ipmmu-vmsa.o: in function `.L0 ':
>>> ipmmu-vmsa.c:(.text+0x145e): undefined reference to `alloc_io_pgtable_ops'
>>>
>>> Add RISCV as an allowed ARCH dependency to fix these problems.
>>>
>>> Fixes: d286a58bc8f4 ("iommu: Tidy up io-pgtable dependencies")
>>> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>>> Cc: Joerg Roedel <joro@xxxxxxxxxx>
>>> Cc: Will Deacon <will@xxxxxxxxxx>
>>> Cc: Robin Murphy <robin.murphy@xxxxxxx>
>>> Cc: iommu@xxxxxxxxxxxxxxx
>>> Cc: Conor Dooley <conor@xxxxxxxxxx>
>>> Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
>>> ---
>>>  drivers/iommu/Kconfig |    2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff -- a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
>>> --- a/drivers/iommu/Kconfig
>>> +++ b/drivers/iommu/Kconfig
>>> @@ -32,7 +32,7 @@ config IOMMU_IO_PGTABLE
>>>  config IOMMU_IO_PGTABLE_LPAE
>>>       bool "ARMv7/v8 Long Descriptor Format"
>>
>> I'm probably missing something here, but why would we want to enable
>> "ARMv7/v8 Long Descriptor Format" on RISC-V?
> 
> Indeed, we should not enable it, unless compile-testing.
> 
>> Would it not be better to make the Renesas depend on, rather than
>> select the option? It does seem highly arch specific, and I feel like
>> Geert previously mentioned that the RZ/Five (their RISC-V offering)
>> didn't use it.
> 
> I think the IPMMU_VMSA dependency should gain
> 
>         depends on ARM || ARM64 || COMPILE_TEST

so like this?
Or did you mean to drop the ARCH_RENESAS part also?


 config IPMMU_VMSA
        bool "Renesas VMSA-compatible IPMMU"
-       depends on ARCH_RENESAS || COMPILE_TEST
+       depends on ARCH_RENESAS || ARM || ARM64 || COMPILE_TEST

The failing config file has ARCH_RENESAS=y.  After the change above, I still get:

WARNING: unmet direct dependencies detected for IOMMU_IO_PGTABLE_LPAE
  Depends on [n]: IOMMU_SUPPORT [=y] && (ARM || ARM64 || COMPILE_TEST [=n]) && !GENERIC_ATOMIC64 [=n]
  Selected by [y]:
  - IPMMU_VMSA [=y] && IOMMU_SUPPORT [=y] && (ARCH_RENESAS [=y] || ARM || ARM64 || COMPILE_TEST [=n]) && !GENERIC_ATOMIC64 [=n]


I am attaching the config file.

>>>       select IOMMU_IO_PGTABLE
>>> -     depends on ARM || ARM64 || COMPILE_TEST
>>> +     depends on ARM || ARM64 || RISCV || COMPILE_TEST
>>>       depends on !GENERIC_ATOMIC64    # for cmpxchg64()
>>>       help
>>>         Enable support for the ARM long descriptor pagetable format.
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 

-- 
~Randy

Attachment: rv64-iommu-vmsa.config
Description: application/config