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Date:      Thu, 02 Aug 2001 20:35:25 -0400
From:      Sergey Babkin <babkin@bellatlantic.net>
To:        tlambert2@mindspring.com
Cc:        craig <craiglei@pasia.com.cn>, freebsd-hackers@FreeBSD.ORG
Subject:   Re: How to visit physical memory above 4G?
Message-ID:  <3B69F1CD.F8798A3E@bellatlantic.net>
References:  <002701c11aed$ae1b98a0$051a0a0a@fd.com> <3B68F190.AB04ACB3@mindspring.com>

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Terry Lambert wrote:
> 
> This basically means that the memory is useless as a DMA target
> or source for disk controllers or gigabit ethernet cards, and is
> pretty useless for swap, if you ever have to copy from one section
> to another (e.g. for IPC, SYSV shared memory, mmap'ed files, VM,
> or buffer cache, etc.).

For the PCI cards supporting the 64-bit addresses you can.
(Note that in PCI support of the 64-bit bus is independent of
the 64-bit address space, the 64-bit addresses can be multiplexed
over a physically 32-bit bus).

-SB

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