On Sun, Aug 28, 2011 at 10:42:49PM +0200, Jan
On 2011-08-28 20:54, Alexander Graf wrote:
> On 28.08.2011, at 02:42, Avi Kivity wrote:
>> On 08/26/2011 08:32 AM, ya su wrote:
>>> I met the same problem, tons of hpet vm_exits(vector 209,
>>> address is in the guest vm's
hpet mmio range), even I disable
>>> device in win7 guest vm, it still
produce a larget amount of
>>> when trace-cmd ; I add -no-hpet
to start the vm, it still has
>>> device inside VM.
>>> Does that means the HPET device in VM does not depend on the
>>> emulated hpet device in qemu-kvm? Is there any way to disable
>>> HPET device to prevent so many
>> Looks like a bug to me.
> IIRC disabling the HPET device doesn't remove the entry from the
no? So the guest OS might still think it's there while nothing
responds (read returns -1).
Exactly. We have a fw_cfg interface in place for quite a while now
(though I wonder how the firmware is supposed to tell -no-hpet apart
from QEMU versions that don't provide this data - both return count =
255), but SeaBios still exposes one HPET block at a hard-coded address
There was quite some discussion about the corresponding Seabios
back then but apparently no consensus was found.
Re-reading it, I
Kevin asked for passing the necessary DSDT
fragments from QEMU to the
firmware instead of using a new, proprietary fw_cfg format. Is that
still the key requirement for any patch finally fixing this bug?
My preference would be to use the existing ACPI table passing
interface (fw_cfg slot 0x8000) to pass different ACPI tables to
SeaBIOS doesn't currently allow that interface to override tables
SeaBIOS builds itself, but it's a simple change to rectify that.
When this was last proposed, it was raised that the header information
in the ACPI table may then not match the tables that SeaBIOS builds.
I think I proposed at that time that SeaBIOS could use the header of
the first fw_cfg table (or some other fw_cfg interface) to populate
the headers of its table headers. However, there was no consensus.
Note - the above is in regard to the HPET table. If the HPET entry in
the DSDT needs to be removed then that's a bigger change.