From: Keir Fraser <keir@xensource.com>
To: Trolle Selander <trolle.selander@gmail.com>,
xen-devel@lists.xensource.com
Cc: Mats.Petersson@amd.com, thomas.woller@amd.com
Subject: Re: [PATCH] [HVM] Patches to make HVM capable of running OS/2.
Date: Fri, 16 Mar 2007 12:21:07 +0000 [thread overview]
Message-ID: <C2203C33.BA79%keir@xensource.com> (raw)
In-Reply-To: <515922b50703160507v5da9ad6eg3389c46044a0f8d1@mail.gmail.com>
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On 16/3/07 12:07, "Trolle Selander" <trolle.selander@gmail.com> wrote:
> This is a "minimally intrusive" way to fix an issue that I think should really
> be fixed in a different way.
> Currently, the shared info, ioreq and buffered_io pages are mapped into the
> guest's memory space as the three highest page frames. They are "protected"
> from use by being marked as reserved in the e820 ram map. However, legacy
> software won't know about the e820 call, and since the older e801 call reports
> all ram, including the shared pages, the guest OS will end up using them as
> regular ram with disastrous results.
> This patch makes the older e801 bios call report one 64kb block less memory,
> thus "protecting" the shared pages from older OS's in a similar manner to the
> e820 call, at the expense of 52kb of wasted ram (the e801 call reports memory
> in 64kb blocks, so no way around this).
I think we should reserve a 64kB block just below 0xF0000000 (by marking
E820_RESERVED) and put these Œspecial pages¹ in there. The fact they¹re not
currently mentioned by the e820 map at all is pretty bad ‹ an OS might
decide to remap PCI devices on top of them, for example!
-- Keir
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next prev parent reply other threads:[~2007-03-16 12:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-16 12:07 [PATCH] [HVM] Patches to make HVM capable of running OS/2 Trolle Selander
2007-03-16 12:21 ` Keir Fraser [this message]
2007-03-16 12:45 ` Trolle Selander
2007-03-16 14:10 ` Keir Fraser
2007-03-16 18:22 ` Trolle Selander
2007-03-16 19:07 ` Keir Fraser
2007-03-16 20:11 ` Trolle Selander
2007-03-16 20:28 ` Keir Fraser
-- strict thread matches above, loose matches on Subject: below --
2007-03-21 9:12 ecs user
2007-03-21 12:47 ` Trolle Selander
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