Thread (1 message) 1 message, 1 author, 2016-09-15

Re: [PATCH v7 00/22] Generic DT bindings for PCI IOMMUs and ARM SMMU

From: Auger Eric <hidden>
Date: 2016-09-15 09:29:43
Also in: linux-arm-kernel, linux-iommu 

Hi Robin,

On 14/09/2016 14:53, Robin Murphy wrote:
On 14/09/16 13:32, Auger Eric wrote:
quoted
Hi,
On 14/09/2016 12:35, Robin Murphy wrote:
quoted
On 14/09/16 09:41, Auger Eric wrote:
quoted
Hi,

On 12/09/2016 18:13, Robin Murphy wrote:
quoted
Hi all,

To any more confusing fixups and crazily numbered extra patches, here's
a quick v7 with everything rebased into the right order. The significant
change this time is to implement iommu_fwspec properly from the start,
which ends up being far simpler and more robust than faffing about
introducing it somewhere 'less intrusive' to move toward core code later.

New branch in the logical place:

git://linux-arm.org/linux-rm iommu/generic-v7
For information, as discussed privately with Robin I experience some
regressions with the former and now deprecated dt description.

on my AMD Overdrive board and my old dt description I now only see a
single group:

/sys/kernel/iommu_groups/
/sys/kernel/iommu_groups/0
/sys/kernel/iommu_groups/0/devices
/sys/kernel/iommu_groups/0/devices/e0700000.xgmac

whereas I formerly see

/sys/kernel/iommu_groups/
/sys/kernel/iommu_groups/3
/sys/kernel/iommu_groups/3/devices
/sys/kernel/iommu_groups/3/devices/0000:00:00.0
/sys/kernel/iommu_groups/1
/sys/kernel/iommu_groups/1/devices
/sys/kernel/iommu_groups/1/devices/e0700000.xgmac
/sys/kernel/iommu_groups/4
/sys/kernel/iommu_groups/4/devices
/sys/kernel/iommu_groups/4/devices/0000:00:02.2
/sys/kernel/iommu_groups/4/devices/0000:01:00.1
/sys/kernel/iommu_groups/4/devices/0000:00:02.0
/sys/kernel/iommu_groups/4/devices/0000:01:00.0
/sys/kernel/iommu_groups/2
/sys/kernel/iommu_groups/2/devices
/sys/kernel/iommu_groups/2/devices/e0900000.xgmac
/sys/kernel/iommu_groups/0
/sys/kernel/iommu_groups/0/devices
/sys/kernel/iommu_groups/0/devices/f0000000.pcie

This is the group topology without ACS override. Applying the non
upstreamed "pci: Enable overrides for missing ACS capabilities" I used
to see separate groups for each PCIe components. Now I don't see any
difference with and without ACS override.
OK, having reproduced on my Juno, the problem looks to be that
of_for_each_phandle() leaves err set to -ENOENT after successfully
walking a phandle list, which makes __find_legacy_master_phandle()
always bail out after the first SMMU.

Can you confirm that the following diff fixes things for you?
Well it improves but there are still differences in the group topology.
The PFs now are in group 0.

root@trusty:~# lspci -nk
00:00.0 0600: 1022:1a00
        Subsystem: 1022:1a00
00:02.0 0600: 1022:1a01
00:02.2 0604: 1022:1a02
        Kernel driver in use: pcieport
01:00.0 0200: 8086:1521 (rev 01)
        Subsystem: 8086:0002
        Kernel driver in use: igb
01:00.1 0200: 8086:1521 (rev 01)
        Subsystem: 8086:0002
        Kernel driver in use: igb


with your series + fix:
/sys/kernel/iommu_groups/
/sys/kernel/iommu_groups/3
/sys/kernel/iommu_groups/3/devices
/sys/kernel/iommu_groups/3/devices/0000:00:00.0
/sys/kernel/iommu_groups/1
/sys/kernel/iommu_groups/1/devices
/sys/kernel/iommu_groups/1/devices/e0700000.xgmac
/sys/kernel/iommu_groups/4
/sys/kernel/iommu_groups/4/devices
/sys/kernel/iommu_groups/4/devices/0000:00:02.2
/sys/kernel/iommu_groups/4/devices/0000:00:02.0
/sys/kernel/iommu_groups/2
/sys/kernel/iommu_groups/2/devices
/sys/kernel/iommu_groups/2/devices/e0900000.xgmac
/sys/kernel/iommu_groups/0
/sys/kernel/iommu_groups/0/devices
/sys/kernel/iommu_groups/0/devices/0000:01:00.1
/sys/kernel/iommu_groups/0/devices/f0000000.pcie
/sys/kernel/iommu_groups/0/devices/0000:01:00.0

Before (4.8-rc5):

/sys/kernel/iommu_groups/
/sys/kernel/iommu_groups/3
/sys/kernel/iommu_groups/3/devices
/sys/kernel/iommu_groups/3/devices/0000:00:00.0
/sys/kernel/iommu_groups/1
/sys/kernel/iommu_groups/1/devices
/sys/kernel/iommu_groups/1/devices/e0700000.xgmac
/sys/kernel/iommu_groups/4
/sys/kernel/iommu_groups/4/devices
/sys/kernel/iommu_groups/4/devices/0000:00:02.2
/sys/kernel/iommu_groups/4/devices/0000:01:00.1
/sys/kernel/iommu_groups/4/devices/0000:00:02.0
/sys/kernel/iommu_groups/4/devices/0000:01:00.0
/sys/kernel/iommu_groups/2
/sys/kernel/iommu_groups/2/devices
/sys/kernel/iommu_groups/2/devices/e0900000.xgmac
/sys/kernel/iommu_groups/0
/sys/kernel/iommu_groups/0/devices
/sys/kernel/iommu_groups/0/devices/f0000000.pcie
Your DT claims that f0000000.pcie (i.e. the "platform device" side of
the host controller) owns the IDs 0x100 0x101 0x102 0x103 0x200 0x201
0x202 0x203 0x300 0x301 0x302 0x303 0x400 0x401 0x402 0x403. Thus when
new devices (the PCI PFs) come along *also* claiming those IDs (via the
RID-to-SID assumption), we now detect the aliasing and assign them to
the existing group.

The only way that DT worked without SMR conflicts before is that
f0000000.pcie wasn't actually getting attached to a domain, thus wasn't
getting SMRs allocated (ISTR you _did_ get conflicts back when we first
tried to switch on default domains; that was probably the reason).
Thanks for your explanations. meanwhile I converted the overdrive dt to
the new syntax and it works properly.

However I noticed there are MSI frame iommu mapping although the
device's domain is the default one. There is no check currently in
21/22. I guess this isn't needed?

Thanks

Eric
Robin.
quoted
Thanks

Eric
quoted
Robin

--->8---
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index fa892d25004d..ac4aab97c93a 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -477,7 +477,7 @@ static int __find_legacy_master_phandle(struct
device *dev, void *data)
 			return 1;
 		}
 	it->node = np;
-	return err;
+	return err == -ENOENT ? 0 : err;
 }

 static struct platform_driver arm_smmu_driver;


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Related discussions
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help