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Date: Mon, 19 Aug 2013 15:15:39 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 3/8] vfio: Introduce VFIO address spaces
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To: Alex Williamson <alex.williamson@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, "Michael S . Tsirkin" <mst@redhat.com>, Alexey Kardashevskiy <aik@ozlabs.ru>, qemu-devel@nongnu.org, Alexander Graf <agraf@suse.de>, qemu-ppc@nongnu.org, Paul Mackerras <paulus@samba.org>, David Gibson <david@gibson.dropbear.id.au>

Il 13/08/2013 00:07, Alex Williamson ha scritto:
>> > +    if (pci_iommu_as(pdev) != &address_space_memory) {
>> > +        error_report("vfio: DMA address space must be system memory");
>> > +        return -ENXIO;
> -EFAULT?  It's a bad address of sorts.
> 

Accessing it would SIGSEGV, so it is not really EFAULT.  I would just
use EINVAL, the numeric error code will go away as soon as initfn is
changed to use "Error *" (which is needed to propagate sensible error
messages to the QMP client).

Paolo