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Date: Thu, 15 Oct 2009 11:43:31 +0200
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] Pass the drive's readonly attribute to
	the guest OS
Message-ID: <20091015094331.GE30889@redhat.com>
References: <4AD5F3BD.2040402@redhat.com> <4AD5FEF2.2000308@redhat.com>
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To: Kevin Wolf <kwolf@redhat.com>
Cc: Naphtali Sprei <nsprei@redhat.com>, qemu-devel@nongnu.org

On Thu, Oct 15, 2009 at 11:36:59AM +0200, Kevin Wolf wrote:
> Am 14.10.2009 18:40, schrieb Naphtali Sprei:
> > Naphtali Sprei wrote:
> > <snip>
> >> I'm planning to investigate where qemu should check the read only attribute before exeuting any write command
> >> to drives, would be sent in a different patch.
> > 
> > revisiting it, if guest OS knows it's a read only device and tries to modify it, anyhow, we don't really care about error reporting,
> > as long as qemu doesn't crash (or modify the drive).
> 
> If the right response to a write on a read-only device is defined in the
> specification (and it most probably is), we should still give the right
> response, even though the OS is doing something wrong.
> 
And since our response to write error may be pausing a VM we shouldn't
allow this to be triggered by a guest OS.

--
			Gleb.