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Date: Mon, 04 Mar 2013 13:21:10 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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To: Gleb Natapov <gleb@redhat.com>
CC: Hu Tao <hutao@cn.fujitsu.com>, kvm list <kvm@vger.kernel.org>,
        qemu-devel <qemu-devel@nongnu.org>,
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        "Daniel P. Berrange" <berrange@redhat.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        Jan Kiszka <jan.kiszka@siemens.com>, Blue Swirl <blauwirbel@gmail.com>,
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        Alex Williamson <alex.williamson@redhat.com>,
        Peter Maydell <peter.maydell@linaro.org>
Subject: Re: [PATCH v13 0/8] pv event interface between host and guest
References: <20130303091738.GB23616@redhat.com> <513471F1.5020702@redhat.com> <20130304102131.GK23616@redhat.com> <51347735.9090204@redhat.com> <20130304104301.GL23616@redhat.com> <51347C23.8080802@redhat.com> <20130304105928.GM23616@redhat.com> <51348142.4070206@redhat.com> <20130304112023.GN23616@redhat.com> <513486EC.1050709@redhat.com> <20130304115207.GO23616@redhat.com>
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Il 04/03/2013 12:52, Gleb Natapov ha scritto:
> > Same here, you can remove the panic event port and add debugcon at
> > 0x505.  That's the problematic case.  But if the user goes to that
> > length, I think we can honestly say we don't care.
>
> IMO there is a big difference between well know serial ISA ports and
> PIO ports we allocate for our devices. Later have to be discoverable
> without resorting to probing. On CPU level we do the same with CPUID
> bits instead of relaying on MSRs #GP. On KVM API level we do the same
> with capabilities instead of relying on ioctls returning errors. This
> is not different.

Ok, I see your point now.  Yes, this is a good reason why patching is
better in the long run.

Paolo