From: wangyijing@huawei•com (Yijing Wang)
To: linux-arm-kernel@lists•infradead.org
Subject: Removal of bus->msi assignment breaks MSI with stacked domains
Date: Fri, 21 Nov 2014 09:54:40 +0800 [thread overview]
Message-ID: <546E9B60.9070706@huawei.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1411202355060.6439@nanos>
>> Thomas, let me know if you want to do that. I suppose we could add a new
>> patch to add it back, but that would leave bisection broken for the
>> interval between c167caf8d174 and the patch that adds it back.
>
> Fortunately my irq/irqdomain branch is not immutable yet. So we have
> no problem at that point. I can rebase on your branch until tomorrow
> night. Or just rebase on mainline and we sort out the merge conflicts
> later, i.e. delegate them to Linus so his job of pulling stuff gets
> not completely boring.
Hi Thomas, sorry for my introducing the broken.
>
> What I'm more worried about is whether this intended change is going
> to inflict a problem on Jiangs intention to deduce the MSI irq domain
> from the device, which we really need for making DMAR work w/o going
> through loops and hoops.
>
> I have limited knowledge about the actual scope of iommu (DMAR) units
> versus device/bus/host-controllers, so I would appreciate a proper
> explanation for that from you or Jiang or both.
In my personal opinion, if it's not necessary, we should not put stuff
into pci_dev or pci_bus. If we plan to save msi_controller in pci_bus or
pci_dev.
I have a proposal, I would be appreciated if you could give some comments.
First we refactor pci_host_bridge to make a generic
pci_host_bridge, then we could save pci domain in it to eliminate
arch specific functions. I aslo wanted to save msi_controller as
pci domain, but now Jiang refactor hierarchy irq domain, and
pci devices under the same pci host bridge may need to associate
to different msi_controllers.
So I want to associate a msi_controller finding ops with generic pci_host_bridge,
then every pci device could find its msi_controller/irq_domain by a
common function
E.g
struct msi_controller *pci_msi_controller(struct pci_dev *pdev)
{
struct msi_controller *ctrl;
struct pci_host_bridge *host = find_pci_host_bridge(pdev->bus);
if (host && host->pci_get_msi_controller)
ctrl = pci_host_bridge->pci_get_msi_controller(struct pci_dev *pdev);
return ctrl;
}
If I miss something, please let me know, thanks.
Thanks!
Yijing.
>
> My guts feeling tells me that anything less granular than the bus
> level is wrong and according to my limited knowledge Intel even has
> DMARs which are assigned to a single device it's even more wrong. So
> the proper change would be not to push it from bus to something above
> the bus, but instead make it a per device property.
>
> But my knowledge there is limited, so I rely on the PCI/architecture
> experts to sort that out.
>
> Let me know ASAP.
>
> Thanks,
>
> tglx
>
> .
>
--
Thanks!
Yijing
next prev parent reply other threads:[~2014-11-21 1:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-20 16:31 Removal of bus->msi assignment breaks MSI with stacked domains Marc Zyngier
2014-11-20 21:53 ` Bjorn Helgaas
2014-11-20 23:10 ` Thomas Gleixner
2014-11-20 23:30 ` Bjorn Helgaas
2014-11-21 9:33 ` Marc Zyngier
2014-11-21 1:54 ` Yijing Wang [this message]
2014-11-21 2:25 ` Jiang Liu
2014-11-21 3:46 ` Yijing Wang
2014-11-21 10:00 ` Marc Zyngier
2014-11-21 17:31 ` Bjorn Helgaas
2014-11-22 4:13 ` Yijing Wang
2014-11-21 1:22 ` Yijing Wang
2014-11-21 1:46 ` Thomas Gleixner
2014-11-21 2:03 ` Jiang Liu
2014-11-21 2:12 ` Yijing Wang
2014-11-21 2:05 ` Yijing Wang
2014-11-21 8:46 ` Lucas Stach
2014-11-21 10:29 ` Marc Zyngier
2014-11-21 10:49 ` Thomas Gleixner
2014-11-21 11:30 ` Marc Zyngier
2014-11-21 12:04 ` Yijing Wang
2014-11-21 10:11 ` Marc Zyngier
2014-11-21 11:57 ` Yijing Wang
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