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From:   Thomas Gleixner <tglx@linutronix.de>
To:     David Woodhouse <dwmw2@infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Juergen Gross <jgross@suse.com>,
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        Bjorn Helgaas <bhelgaas@google.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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        Kevin Tian <kevin.tian@intel.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Ashok Raj <ashok.raj@intel.com>, Jon Mason <jdmason@kudzu.us>,
        Allen Hubbe <allenbh@gmail.com>
Subject: Re: [patch V3 16/22] genirq/msi: Provide new domain id based
 interfaces for freeing interrupts
In-Reply-To: <57f3f757aaceccf866172faaf48ab62916f24d8b.camel@infradead.org>
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Date:   Mon, 16 Jan 2023 20:49:02 +0100
Message-ID: <87edrumf9t.ffs@tglx>
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David!

On Mon, Jan 16 2023 at 19:28, David Woodhouse wrote:
> On Mon, 2023-01-16 at 20:22 +0100, Thomas Gleixner wrote:
>> > Tested-by: David Woodhouse <dwmw@amazon.co.uk>
>> >=20
>> > Albeit only under qemu with
>> > https://git.infradead.org/users/dwmw2/qemu.git/shortlog/refs/heads/xen=
fv
>> > and not under real Xen.
>>=20
>> Five levels of emulation. What could possibly go wrong?
>
> It's the opposite =E2=80=94 this is what happened when I threw my toys ou=
t of
> the pram and said, "You're NOT doing that with nested virtualization!".
>
> One level of emulation. We host guests that think they're running on
> Xen, directly in QEMU/KVM by handling the hypercalls and event
> channels, grant tables, etc.
>
> We virtualised Xen itself :)

Groan. Can we please agree on *one* hypervisor instead of growing
emulators for all other hypervisors in each of them :)

> Now you have no more excuses for breaking Xen guest mode!

No cookies, you spoilsport! :)

        tglx