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From: Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
To: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>,
	Alexey Kardashevskiy
	<aik-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org>
Cc: Jike Song <jike.song-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	"kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	linux-pci <linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"open list:INTEL IOMMU \(VT-d\)"
	<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
	Yongji Xie <elohimes-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Yongji Xie
	<xyjxie-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
	Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
	David Gibson
	<david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>
Subject: Re: [PATCH kernel v4 4/6] iommu: Set PCI_BUS_FLAGS_MSI_REMAP on iommu driver initialization
Date: Wed, 26 Jul 2017 21:33:59 +1000	[thread overview]
Message-ID: <1501068839.2792.27.camel@kernel.crashing.org> (raw)
In-Reply-To: <20170726095053.GG15833-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>

On Wed, 2017-07-26 at 11:50 +0200, Joerg Roedel wrote:
> > 3. Create IOMMU_DOMAIN_UNMANAGED IOMMU domains for PPC64/powernv IOMMU
> > groups and only define capable() hook to report IOMMU_CAP_INTR_REMAP;
> > others already use these IOMMU domains. VFIO-PCI's mmap() hook could then
> > check the capability via iommu_capable(bus). The problems is as Robin said:
> > "iommu_capable() is a fundamentally broken and unworkable interface
> > anyway"; however it is still not clear to me why it is unworkable in this
> > particular case of isolation checking.
> 
> That one is wrong, IRQ remapping is not a property of a domain. A domain
> is an abstraction for a device address space. Attaching IRQ information
> there is just wrong.

Except it somewhat is ... an MSI is a store in the device address
space, the way MSIs are handled and/or filtered can be considered a
property of the domain. In our case, it's the exact same piece of HW
that defines domains and which MSIs they are allowed to generate.

Cheers,
Ben.

  parent reply	other threads:[~2017-07-26 11:33 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-30  5:24 [PATCH kernel v4 0/6] vfio-pci: Add support for mmapping MSI-X table Alexey Kardashevskiy
2017-06-30  5:24 ` [PATCH kernel v4 1/6] PCI: Add a new PCI_BUS_FLAGS_MSI_REMAP flag Alexey Kardashevskiy
2017-07-10 19:20   ` Bjorn Helgaas
2017-07-11  8:36     ` Alexey Kardashevskiy
2017-06-30  5:24 ` [PATCH kernel v4 2/6] PCI: Set PCI_BUS_FLAGS_MSI_REMAP if MSI controller enables IRQ remapping Alexey Kardashevskiy
2017-06-30  5:24 ` [PATCH kernel v4 3/6] PCI: Set PCI_BUS_FLAGS_MSI_REMAP if IOMMU have capability of " Alexey Kardashevskiy
2017-07-01 10:27   ` kbuild test robot
2017-06-30  5:24 ` [PATCH kernel v4 4/6] iommu: Set PCI_BUS_FLAGS_MSI_REMAP on iommu driver initialization Alexey Kardashevskiy
     [not found]   ` <20170630052436.15212-5-aik-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org>
2017-07-10 19:23     ` Bjorn Helgaas via iommu
     [not found]       ` <CAErSpo4pAZfDx5p_S9Z8jR_ctH=ZrkgG6aNaNmPaN2H77dgEgQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-07-11 10:39         ` Robin Murphy
2017-07-12  2:47           ` Alexey Kardashevskiy
2017-07-19  5:12           ` Benjamin Herrenschmidt
2017-07-19 10:02       ` Alexey Kardashevskiy
2017-07-25  6:09         ` Alexey Kardashevskiy
     [not found]         ` <b444851a-3240-f98f-04b9-0223649ea856-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org>
2017-07-26  9:50           ` Joerg Roedel
     [not found]             ` <20170726095053.GG15833-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2017-07-26 11:33               ` Benjamin Herrenschmidt [this message]
2017-07-12  7:04   ` Jike Song
2017-07-12  7:28     ` Alexey Kardashevskiy
2017-06-30  5:24 ` [PATCH kernel v4 5/6] pci-ioda: Set PCI_BUS_FLAGS_MSI_REMAP for IODA host bridge Alexey Kardashevskiy
2017-06-30  5:24 ` [PATCH kernel v4 6/6] vfio-pci: Allow to expose MSI-X table to userspace if interrupt remapping is enabled Alexey Kardashevskiy
2017-07-10  2:20 ` [PATCH kernel v4 0/6] vfio-pci: Add support for mmapping MSI-X table Alexey Kardashevskiy
2017-07-10 19:11 ` Bjorn Helgaas

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