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From: Artyom Tarasenko <atar4qemu@googlemail.com>
Date: Fri, 7 May 2010 18:26:38 +0200
Message-ID: <q2pfb8d4f71005070926y8d6f9208y9a6b5eb6a70b77cb@mail.gmail.com>
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Subject: [Qemu-devel] phys_page_find bug?
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To: qemu-devel <qemu-devel@nongnu.org>, Blue Swirl <blauwirbel@gmail.com>, Richard Henderson <rth@twiddle.net>

phys_page_find (exec.c) returns sometimes a page for addresses where
nothing is connected.

One example, done with qemu-system-sparc -M SS-20

ok f13ffff0 2f spacec@ .

// The address translates correctly, in cpu_physical_memory_rw
// addr== 0xff13ffff0 (where nothing is connected)
// but then phys_page_find returns a nonzero and produces

Unassigned mem read access of 1 byte to 0000000ff15ffff0 from xxxxx

(note the "5" in the line above where "3" is expected)

I wonder if this is only true for non-wired addresses, or whether
phys_page_find can also
find wrong pages for the addresses where something is connected?

Or is my assumption is wrong and phys_page_find can return a page for
not-connected
addresses and the bug is actually in cpu_physical_memory_rw ?

Is the qemu algorithm of working with the physical address space
described somewhere?

-- 
Regards,
Artyom Tarasenko

solaris/sparc under qemu blog: http://tyom.blogspot.com/