From: "andrzej zaborowski" <balrogg@gmail.com>
To: qemu-devel@nongnu.org
Cc: Glauber Costa <glommer@redhat.com>,
Ian.Jackson@eu.citrix.com, avi@redhat.com, kvm@vger.kernel.org,
stefano.stabellini@eu.citrix.com
Subject: Re: [Qemu-devel] Re: [PATCH 1/5] re-register whole area upon lfb unmap.
Date: Thu, 25 Dec 2008 21:08:07 +0100 [thread overview]
Message-ID: <fb249edb0812251208y28ab052fg4ba7c73642a9f90a@mail.gmail.com> (raw)
In-Reply-To: <494966BA.7000100@codemonkey.ws>
2008/12/17 Anthony Liguori <anthony@codemonkey.ws>:
> Glauber Costa wrote:
>>
>> set phys_offset correctly for the whole vga area when unmapping linear
>> vram
>> (for vga optimization). We first register the old pieces as unassigned
>> memory, to make things easier for kvm (and possibly other slot based
>> implementations in the future). Replacing the region directly would
>> make the slot management significantly more complex.
>>
>
> This change worries me because it involves explicitly unassigning slots and
> then assigning a new, bigger slot. This is not necessary for TCG. It
> suggests to me that there's a bug in the kvm slot code and that we're
> changing QEMU to work around it.
>
> That will means there may be other places in the code that are completely
> valid, but exercise this bug.
>
> Or is this purely an optimization?
It also changes the semantics because IO callbacks are now passed
offsets from regions starts instead of absolute addresses. I'm not
able to tell if the change is for good or for bad though.
Cheers
next prev parent reply other threads:[~2008-12-25 20:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-17 20:46 [Qemu-devel] [PATCH 0/5] Replace tcg memory functions Glauber Costa
2008-12-17 20:46 ` [Qemu-devel] [PATCH 1/5] re-register whole area upon lfb unmap Glauber Costa
2008-12-17 20:46 ` [Qemu-devel] [PATCH 2/5] isolate io handling routing Glauber Costa
2008-12-17 20:47 ` [Qemu-devel] [PATCH 3/5] replace cpu_physical_memory_rw Glauber Costa
2008-12-17 20:47 ` [Qemu-devel] [PATCH 4/5] hook cpu_register_physical_mem Glauber Costa
2008-12-17 20:47 ` [Qemu-devel] [PATCH 5/5] cache slot lookup Glauber Costa
2008-12-18 9:41 ` [Qemu-devel] " Avi Kivity
2008-12-18 10:48 ` Glauber Costa
2008-12-18 11:00 ` Daniel P. Berrange
2008-12-18 11:07 ` Glauber Costa
2008-12-18 11:24 ` Avi Kivity
2008-12-17 20:56 ` [Qemu-devel] Re: [PATCH 3/5] replace cpu_physical_memory_rw Anthony Liguori
2008-12-17 21:00 ` Glauber Costa
2008-12-17 20:54 ` [Qemu-devel] Re: [PATCH 2/5] isolate io handling routing Anthony Liguori
2008-12-17 20:53 ` [Qemu-devel] Re: [PATCH 1/5] re-register whole area upon lfb unmap Anthony Liguori
2008-12-25 20:08 ` andrzej zaborowski [this message]
2008-12-22 17:10 ` [Qemu-devel] [PATCH 0/5] Replace tcg memory functions Ian Jackson
2008-12-22 17:18 ` Glauber Costa
2008-12-22 17:22 ` Ian Jackson
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