Re: [PATCH] Xen/i386 cleanups - AGP bus/phys cleanups

From: Christoph Hellwig
Date: Wed Mar 16 2005 - 09:36:33 EST


On Wed, Mar 16, 2005 at 11:48:29AM +0000, Keir Fraser wrote:
> This patch cleans up AGP driver treatment of bus/device memory. Every
> use of virt_to_phys/phys_to_virt should properly be converting between
> virtual and bus addresses: this distinction really matters for the Xen
> hypervisor.

It's bogus either way. You must never use virt_to_phys or virt_to_bus
for bus address. For systems with an IOMMU there's no 1:1 mapping.

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