Re: [Qemu-stable] [Qemu-arm] [PATCH v4 2/2] arm_gicv3_kvm: kvm_dist_get/put: skip the registers banked by GICR

[Peter Maydell]

On 30 May 2018 at 02:42, Shannon Zhao <address@hidden> wrote:
>
>
> On 2018/5/29 22:44, Peter Maydell wrote:
>> This is where we should have a comment explaining the bug and
>> what the migration data from the old broken QEMU looks like; something
>> like:
>>
>>     /* Older versions of QEMU had a bug in the handling of state save/restore
>>      * to the KVM GICv3: they got the offset in the bitmap arrays wrong,
>>      * so that instead of the data for external interrupts 32 and up
>>      * starting at bit position 32 in the bitmap, it started at bit
>>      * position 0.
> Not right here. for_each_dist_irq_reg starts from 32 and if irq is 32
> and gic_bmp_ptr32(bmp, irq) points bit 32, while offset passed to KVM is
> 0, then it will get the GICR values for bit 32 ~ bit 63. So the data
> looks like below:
> [00...0 00..0 xx..x ...]
> So we need to move the data down by 32 bits.

Yes, you're right.

thanks
-- PMM