From: Paolo Bonzini <pbonzini@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
alex.williamson@redhat.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 15/17] pci: use memory core for iommu support
Date: Wed, 01 May 2013 18:07:23 +0200 [thread overview]
Message-ID: <51813DBB.7060305@redhat.com> (raw)
In-Reply-To: <20130501050634.GA14106@truffula.fritz.box>
Il 01/05/2013 07:06, David Gibson ha scritto:
>>> + + /* FIXME: inherit memory region from bus creator */ +
>>> memory_region_init_alias(mr, "iommu-nop", get_system_memory(),
>>> 0, INT64_MAX); + return mr;
> I don't see the reason for creating a new alias for each PCI
> device. Can't pci_dev->iommu just point directly to
> get_system_memory() in the normal case?
>
> In addition to creating additional objects, having these aliases
> makes it much les obvious how to tell if two PCI devices share an
> IOMMU address space. We have to be able to determine that for
> VFIO, since devices which share an address space in the host
> clearly can't be assigned to different address spaces in the
> guest.
Right, the alias that is needed to enable/disable bus-mastering is
created already below, so pci_dev->iommu can be shared (as it is in the
spapr case).
Paolo
next prev parent reply other threads:[~2013-05-01 16:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1367378320-9246-1-git-send-email-david@gibson.dropbear.id.au>
[not found] ` <1367378320-9246-7-git-send-email-david@gibson.dropbear.id.au>
2013-05-01 4:02 ` [Qemu-devel] [PATCH 07/17] memory: add address_space_valid David Gibson
2013-05-01 7:17 ` Paolo Bonzini
[not found] ` <1367378320-9246-11-git-send-email-david@gibson.dropbear.id.au>
2013-05-01 4:38 ` [Qemu-devel] [PATCH 11/17] spapr: convert TCE API to use an opaque type David Gibson
[not found] ` <1367378320-9246-13-git-send-email-david@gibson.dropbear.id.au>
2013-05-01 4:46 ` [Qemu-devel] [PATCH 13/17] spapr: use memory core for iommu support David Gibson
[not found] ` <1367378320-9246-14-git-send-email-david@gibson.dropbear.id.au>
2013-05-01 4:49 ` [Qemu-devel] [PATCH 14/17] dma: eliminate old-style IOMMU support David Gibson
[not found] ` <1367378320-9246-15-git-send-email-david@gibson.dropbear.id.au>
2013-05-01 5:06 ` [Qemu-devel] [PATCH 15/17] pci: use memory core for iommu support David Gibson
2013-05-01 16:07 ` Paolo Bonzini [this message]
[not found] ` <1367378320-9246-16-git-send-email-david@gibson.dropbear.id.au>
2013-05-01 5:16 ` [Qemu-devel] [PATCH 16/17] spapr_vio: take care of creating our own AddressSpace/DMAContext David Gibson
2013-05-01 16:09 ` Paolo Bonzini
2013-05-02 2:24 ` David Gibson
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