RE: [Xen-devel] [PATCH] Move RTC from Qemu to HV

["Yang, Xiaowei" <xiaowei.yang@xxxxxxxxx>]

>Xen has a view of UTC, kept up to date by domain0. There is also
facility
>already to set a per-domain offset from UTC (XEN_DOMCTL_settimeoffset).
So
>Xen is quite capable of setting all time fields itself.
>
>As for the rest of the CMOS fields, I believe that they only contain
some
>basic info like boot order? This is only derived by qemu from
command-line
>switches -- we could make xend push down initialiser values instead.
Maybe
>only pushing implementation of time-related CMOS bytes[*] to Xen in the
>first instance does make sense though...
>
>[*] That's more than 10 bytes though, right? There are status and
control
>registers at indexes 0xa-0xd?


Keir,
This is the revised patch, which adopts your suggestion to handle CMOS
ram. No CMOS data in the shared io page any more. RTC in HV maintains
the first 14 (10 is a typo:) time/interrupt related bytes. Initial CMOS
date equals to Xen wallclock + time_offset_seconds. Qemu handles the
rest CMOS ram. 

The patch also considers SVM guest. For Ia64 part, as it has no problem
as x86, the patch doesn't affect it.

Thanks, 
Xiaowei

Attachment: rtc_hv.patch
Description: rtc_hv.patch

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