Subject: Re: [edk2] Xen OVMF early discussions
From: Bei Guan <firstname.lastname@example.org>
To: Andrei Warkentin <email@example.com>
Date: 2011-05-20 09:15:39
0xFFFFFFFF implies that -
On Thu, May 19, 2011 at 12:09 AM, Bei Guan <firstname.lastname@example.org> wrote:
> Is this functionIoRead32 to read from the timer register as you said?
> From the comment among the code, I know the code IoRead32 (TimerBaseBar +
> ACPI_TIMER_OFFSET) is to read the "current tick counter of ACPI". Why the
> tick counter is alwayFFFFFFFF?
1) ACPI timer is not present
2) We're reading the wrong address
Since we know (2) isn't the case, then it must be (1). Your HVM config
file has the line "acpi=0". That's your problem. Get rid of it, or
change it to "acpi=1" and it should work for you.
In general, though, you would proceed by -
a) figuring out what component is responsible for ACPI timer. (xen
hypervisor in this case)
b) figuring out the conditions where the ACPI timer would not be emulated by Xen
c) Instrument hypverisor, or otherwise verify the conditions
d) figure out what influences the conditions (hint: must be the hvm
builder, xend and xm probably involved too)
e) arrive at conclusion that "acpi=0" causes the ACPI timer to not be
enabled inside Xen for this domain