[PATCH v2] Platform/RaspberryPi: Only enable IORT when 3G limit is disabled.

[PATCH v2] Platform/RaspberryPi: Only enable IORT when 3G limit is disabled.

[jlinton]

From: Jeremy Linton <jeremy.linton@arm.com>

The 3G limit, and the 2G IORT are intended to solve
the same linux problem. They limit PCI DMA operations
to the first 3G of RAM. Older linux kernels, as
used with RHEL/Centos, trigger an assertion*
when a DMA operation starts at a range that
doesn't fit within the 2G range specified by the IORT.

The simple solution is to only enable the IORT
when the 3G flag is disabled and there is more
than 3G installed.

* https://github.com/pftf/RPi4/issues/123

Fixes: dac891da5cf3 ("Platform/RaspberryPi/AcpiTables: add a IORT ACPI table to limit XHCI DMA")
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
 Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
index 19ef950f10..578f5ead8f 100644
--- a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
+++ b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
@@ -755,6 +755,12 @@ HandleDynamicNamespace (
     DEBUG ((DEBUG_ERROR, "Found namespace table not in table list.\n"));
 
     return FALSE;
+  case SIGNATURE_32 ('I', 'O', 'R', 'T'):
+    // only enable the IORT on machines with >3G and no limit
+    // to avoid problems with rhel/centos and other older OSs
+    if (PcdGet32 (PcdRamLimitTo3GB) || !PcdGet32 (PcdRamMoreThan3GB)) {
+      return FALSE;
+    }
   }
 
   return TRUE;
-- 
2.13.7

Re: [PATCH v2] Platform/RaspberryPi: Only enable IORT when 3G limit is disabled.

[Andrei Warkentin]

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Reviewed-by: Andrei Warkentin <awarkentin@vmware.com>
________________________________
From: jlinton <lintonrjeremy@gmail.com>
Sent: Wednesday, February 17, 2021 12:07 AM
To: devel@edk2.groups.io <devel@edk2.groups.io>
Cc: pete@akeo.ie <pete@akeo.ie>; Andrei Warkentin <awarkentin@vmware.com>; samer.el-haj-mahmoud@arm.com <samer.el-haj-mahmoud@arm.com>; leif@nuviainc.com <leif@nuviainc.com>; ardb+tianocore@kernel.org <ardb+tianocore@kernel.org>; Jeremy Linton <jeremy.linton@arm.com>
Subject: [PATCH v2] Platform/RaspberryPi: Only enable IORT when 3G limit is disabled.

From: Jeremy Linton <jeremy.linton@arm.com>

The 3G limit, and the 2G IORT are intended to solve
the same linux problem. They limit PCI DMA operations
to the first 3G of RAM. Older linux kernels, as
used with RHEL/Centos, trigger an assertion*
when a DMA operation starts at a range that
doesn't fit within the 2G range specified by the IORT.

The simple solution is to only enable the IORT
when the 3G flag is disabled and there is more
than 3G installed.

* https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fpftf%2FRPi4%2Fissues%2F123&amp;data=04%7C01%7Cawarkentin%40vmware.com%7C0c1dc1458ac14a84867b08d8d30a613a%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C0%7C1%7C637491388819273969%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=VlStuFf%2F5bvIAMarB%2F2djY64J7GDa1zEVMB61%2Fwjgn8%3D&amp;reserved=0

Fixes: dac891da5cf3 ("Platform/RaspberryPi/AcpiTables: add a IORT ACPI table to limit XHCI DMA")
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
 Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
index 19ef950f10..578f5ead8f 100644
--- a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
+++ b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
@@ -755,6 +755,12 @@ HandleDynamicNamespace (
     DEBUG ((DEBUG_ERROR, "Found namespace table not in table list.\n"));



     return FALSE;

+  case SIGNATURE_32 ('I', 'O', 'R', 'T'):

+    // only enable the IORT on machines with >3G and no limit

+    // to avoid problems with rhel/centos and other older OSs

+    if (PcdGet32 (PcdRamLimitTo3GB) || !PcdGet32 (PcdRamMoreThan3GB)) {

+      return FALSE;

+    }

   }



   return TRUE;

--
2.13.7


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Re: [PATCH v2] Platform/RaspberryPi: Only enable IORT when 3G limit is disabled.

[Ard Biesheuvel]

On Wed, 17 Feb 2021 at 07:22, Andrei Warkentin <awarkentin@vmware.com> wrote:
>
> Reviewed-by: Andrei Warkentin <awarkentin@vmware.com>
> _

Pushed as 2cad1bd782b5..41b54dbb6803

Thanks all

_______________________________
> From: jlinton <lintonrjeremy@gmail.com>
> Sent: Wednesday, February 17, 2021 12:07 AM
> To: devel@edk2.groups.io <devel@edk2.groups.io>
> Cc: pete@akeo.ie <pete@akeo.ie>; Andrei Warkentin <awarkentin@vmware.com>; samer.el-haj-mahmoud@arm.com <samer.el-haj-mahmoud@arm.com>; leif@nuviainc.com <leif@nuviainc.com>; ardb+tianocore@kernel.org <ardb+tianocore@kernel.org>; Jeremy Linton <jeremy.linton@arm.com>
> Subject: [PATCH v2] Platform/RaspberryPi: Only enable IORT when 3G limit is disabled.
>
> From: Jeremy Linton <jeremy.linton@arm.com>
>
> The 3G limit, and the 2G IORT are intended to solve
> the same linux problem. They limit PCI DMA operations
> to the first 3G of RAM. Older linux kernels, as
> used with RHEL/Centos, trigger an assertion*
> when a DMA operation starts at a range that
> doesn't fit within the 2G range specified by the IORT.
>
> The simple solution is to only enable the IORT
> when the 3G flag is disabled and there is more
> than 3G installed.
>
> * https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fpftf%2FRPi4%2Fissues%2F123&amp;data=04%7C01%7Cawarkentin%40vmware.com%7C0c1dc1458ac14a84867b08d8d30a613a%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C0%7C1%7C637491388819273969%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=VlStuFf%2F5bvIAMarB%2F2djY64J7GDa1zEVMB61%2Fwjgn8%3D&amp;reserved=0
>
> Fixes: dac891da5cf3 ("Platform/RaspberryPi/AcpiTables: add a IORT ACPI table to limit XHCI DMA")
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
>  Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
> index 19ef950f10..578f5ead8f 100644
> --- a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
> +++ b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
> @@ -755,6 +755,12 @@ HandleDynamicNamespace (
>      DEBUG ((DEBUG_ERROR, "Found namespace table not in table list.\n"));
>
>
>
>      return FALSE;
>
> +  case SIGNATURE_32 ('I', 'O', 'R', 'T'):
>
> +    // only enable the IORT on machines with >3G and no limit
>
> +    // to avoid problems with rhel/centos and other older OSs
>
> +    if (PcdGet32 (PcdRamLimitTo3GB) || !PcdGet32 (PcdRamMoreThan3GB)) {
>
> +      return FALSE;
>
> +    }
>
>    }
>
>
>
>    return TRUE;
>
> --
> 2.13.7
>