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Re: [Qemu-devel] [PATCH 3/7] target-arm: mark up cpregs for no-migrate o
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH 3/7] target-arm: mark up cpregs for no-migrate or raw access |
Date: |
Thu, 30 May 2013 23:42:37 +0100 |
On 30 May 2013 23:38, Christoffer Dall <address@hidden> wrote:
> On Thu, May 30, 2013 at 11:27:01PM +0100, Peter Maydell wrote:
>> On 30 May 2013 23:13, Christoffer Dall <address@hidden> wrote:
>> > CONTEXTIDR seems to be such an example. ?
>>
>> In this specific case I decided it was safe to let the non-raw
>> write function do a tlb_flush(). Looking again that is kinda
>> expensive though, so we should probably mark these registers
>> up with raw_write functions.
>>
>
> Migration is sort of an expensive operation, so not sure if it's worth
> it.
It'll also happen every time we drop out to a gdb attached
to the VM. But yes, this definitely isn't on any fast paths.
> I am mostly worries about the case where we would miss raw read/write
> functions and that could be hard to track down in the case where
> migration fails, but I don't really have great suggestions on how to
> ensure this.
That's the one argument for insisting on a raw function -- it
does mean that when looking at code and patches you can see
it's an explicit decision on how to handle the situation.
thanks
-- PMM
[Qemu-devel] [PATCH 1/7] target-arm: Allow special cpregs to have flags set, Peter Maydell, 2013/05/17
[Qemu-devel] [PATCH 4/7] target-arm: Convert TCG to using (index, value) list for cp migration, Peter Maydell, 2013/05/17
[Qemu-devel] [PATCH 5/7] target-arm: Initialize cpreg list from KVM when using KVM, Peter Maydell, 2013/05/17
Re: [Qemu-devel] [PATCH 0/7] target-arm: cpregs list for migration, kvm reset, Christoffer Dall, 2013/05/31