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From: "Michael R. Hines" <mrhines@linux.vnet.ibm.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: aliguori@us.ibm.com, quintela@redhat.com, qemu-devel@nongnu.org,
	owasserm@redhat.com, abali@us.ibm.com, mrhines@us.ibm.com,
	gokul@us.ibm.com, pbonzini@redhat.com, chegu_vinod@hp.com,
	knoel@redhat.com
Subject: Re: [Qemu-devel] [PATCH 3/6] rdma: core logic
Date: Fri, 28 Jun 2013 10:00:38 -0400	[thread overview]
Message-ID: <51CD9706.1000804@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAFEAcA9nV_i6bHM_nzvYRHk4uoq9RQwp4+kooCCUrrVxnbuHWw@mail.gmail.com>

On 06/28/2013 09:28 AM, Peter Maydell wrote:
> On 28 June 2013 14:23, Michael R. Hines <mrhines@linux.vnet.ibm.com> wrote:
>>> I assume from the PACKED annotations (do we really need both,
>>> incidentally) that this is shared with either the guest or
>>> with another instance of QEMU. Are there definitely no
>>> endianness issues to deal with here?
>>
>> I have ntohl()/htonl() on the protocol headers, but I did not
>> add them for the data portions of the protocol.
>>
>>
>> Is endianess for the data a big issue when you are assume the migration
>> is happening across identical CPU architectures?
> Well:
>   * is that a reasonable assumption? (why?)

I would yes, because we're dealing raw guest RAM.
Migration of memory would not work across a different architecture
(particularly page tables - which would need to be canonicalized
and de-canonicalized).

>   * if you try this on some setup where it's not true, do we
>     fail helpfully or obscurely?

Shouldn't a check like that occur before the migration actually begins?
Is this specific to RDMA?

  reply	other threads:[~2013-06-28 14:10 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-27 22:44 [Qemu-devel] [PATCH 0/6] rdma: core logic and unpin support mrhines
2013-06-27 22:44 ` [Qemu-devel] [PATCH 1/6] rdma: update documentation to reflect new " mrhines
2013-06-27 23:09   ` Eric Blake
2013-06-28 13:17     ` Michael R. Hines
2013-06-27 22:44 ` [Qemu-devel] [PATCH 2/6] rdma: introduce ram_handle_compressed() mrhines
2013-06-27 22:56   ` Peter Maydell
2013-06-28  7:17     ` Paolo Bonzini
2013-06-27 22:44 ` [Qemu-devel] [PATCH 3/6] rdma: core logic mrhines
2013-06-27 23:16   ` Peter Maydell
2013-06-28 13:23     ` Michael R. Hines
2013-06-28 13:28       ` Peter Maydell
2013-06-28 14:00         ` Michael R. Hines [this message]
2013-06-28 14:07           ` Peter Maydell
2013-06-28 14:22             ` Michael R. Hines
2013-06-28  7:33   ` Paolo Bonzini
2013-06-28 14:11     ` Michael R. Hines
2013-06-27 22:44 ` [Qemu-devel] [PATCH 4/6] rdma: allow state transitions between other states besides ACTIVE mrhines
2013-06-27 23:10   ` Eric Blake
2013-06-28  7:34     ` Paolo Bonzini
2013-06-27 22:44 ` [Qemu-devel] [PATCH 5/6] rdma: introduce MIG_STATE_NONE and change MIG_STATE_SETUP state transition mrhines
2013-06-27 22:44 ` [Qemu-devel] [PATCH 6/6] rdma: account for the time spent in MIG_STATE_SETUP through QMP mrhines

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