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From: David Gibson <david@gibson.dropbear.id.au>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: qemu-devel@nongnu.org, qemu-ppc@nongnu.org, paulus@samba.org,
	agraf@suse.de, Anton Blanchard <anton@samba.org>
Subject: Re: [Qemu-devel] [PATCH] target-ppc: Use right page size with hash table lookup
Date: Thu, 29 Jan 2015 11:48:47 +1100	[thread overview]
Message-ID: <20150129004847.GK14681@voom> (raw)
In-Reply-To: <1422282118-22507-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>

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On Mon, Jan 26, 2015 at 07:51:58PM +0530, Aneesh Kumar K.V wrote:
> We look at two sizes specified in ISA (4K, 64K). If not found matching,
> we consider it 16MB.
> 
> Without this patch we would fail to lookup address above 16MB range.
> Below 16MB happened to work before because the kernel have a liner
> mapping and we always looked up hash for 0xc000000000000000. The
> actual real address was computed by using the 16MB offset
> with the real address found with the above hash.
> 
> Without Fix:
> (gdb) x/16x 0xc000000001000000
> 0xc000000001000000 <list_entries+453208>:       Cannot access memory at address 0xc000000001000000
> (gdb)
> 
> With Fix:
> (gdb)  x/16x 0xc000000001000000
> 0xc000000001000000 <list_entries+453208>:       0x00000000      0x00000000      0x00000000      0x00000000
> 0xc000000001000010 <list_entries+453224>:       0x00000000      0x00000000      0x00000000      0x00000000
> 0xc000000001000020 <list_entries+453240>:       0x00000000      0x00000000      0x00000000      0x00000000
> 0xc000000001000030 <list_entries+453256>:       0x00000000      0x00000000      0x00000000      0x00000000
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

This doesn't fully implement the sllp page size encodings, but it's
certainly better than what's there now.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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  reply	other threads:[~2015-01-29  1:49 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-26 14:21 [Qemu-devel] [PATCH] target-ppc: Use right page size with hash table lookup Aneesh Kumar K.V
2015-01-29  0:48 ` David Gibson [this message]
2015-01-29 13:11   ` Alexander Graf

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