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Subject: Re: [PATCH v7 0/7] KVM: x86: Allow Qemu/KVM to use PVH entry point
To:     Maran Wilson <maran.wilson@oracle.com>, x86@kernel.org,
        xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, jgross@suse.com
Cc:     boris.ostrovsky@oracle.com, bp@suse.de,
        dave.hansen@linux.intel.com, davem@davemloft.net,
        gregkh@linuxfoundation.org, hpa@zytor.com, jpoimboe@redhat.com,
        kirill.shutemov@linux.intel.com, linus.walleij@linaro.org,
        luto@kernel.org, mchehab@kernel.org, mingo@redhat.com,
        rdunlap@infradead.org, tglx@linutronix.de, thomas.lendacky@amd.com,
        hch@infradead.org, roger.pau@citrix.com, rkrcmar@redhat.com,
        Stefan Hajnoczi <stefanha@redhat.com>,
        Stefano Garzarella <sgarzare@redhat.com>,
        Liam Merwick <liam.merwick@oracle.com>,
        George Kennedy <george.kennedy@oracle.com>
References: <1523920175-27287-1-git-send-email-maran.wilson@oracle.com>
 <9aeeaf85-6ecf-c1e2-640a-657f5bb0f8ef@redhat.com>
 <bf0112de-8ceb-d1e4-d787-bf6bde7a1f14@oracle.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
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Message-ID: <a0156b30-2e67-b68b-d555-a255acf2098e@redhat.com>
Date:   Mon, 19 Nov 2018 19:25:43 +0100
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Sender: linux-kernel-owner@vger.kernel.org
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On 16/11/18 18:17, Maran Wilson wrote:
> On 11/16/2018 2:46 AM, Paolo Bonzini wrote:
>> On 17/04/18 01:09, Maran Wilson wrote:
>>> For certain applications it is desirable to rapidly boot a KVM virtual
>>> machine. In cases where legacy hardware and software support within the
>>> guest is not needed, Qemu should be able to boot directly into the
>>> uncompressed Linux kernel binary without the need to run firmware.
>>>
>>> There already exists an ABI to allow this for Xen PVH guests and the ABI
>>> is supported by Linux and FreeBSD:
>>>
>>>     https://xenbits.xen.org/docs/unstable/misc/pvh.html
>>>
>>> This patch series would enable Qemu to use that same entry point for
>>> booting KVM guests.
>> Hi Maran, what happened to this series (and to the QEMU work)?
> 
> Hi Paolo,
> 
> Thank you for the reminder. Sorry, I have been wanting to continue this
> work for a while now, but our team has been pulled in other directions
> and this one ended up getting temporarily pushed down the priority stack.
> 
> Let me discuss with my management and get back to you. I do want (and
> intend) to support and push this over the finish line.
> 
> In the meantime, if there are any folks out there with a specific
> business need for getting this done sooner rather than later

Well, we are interested in using this to avoid the decompression cost of
booting a "container-like" VM image.  I'm not sure what we will do about
that, but certainly getting this included in the upstream projects would
be a prerequisite.

If you really prefer to discuss things offlist, feel free to include me,
Stefan and Stefano.

Paolo

> and are
> able to invest a bit of time to collaborate on the remaining Qemu work,
> please feel free to ping me offline. We have some preliminary Qemu
> patches, but there is some additional work needed before they are ready
> wider review.
> 
> Thanks,
> -Maran