Re: [Qemu-devel] [edk2] OVMF hung on qemu 1.6.0 with KVM

[Laszlo Ersek]

On 08/28/13 13:49, Andreas Färber wrote:
> Am 28.08.2013 13:45, schrieb Laszlo Ersek:
>> (qemu-devel CC'd)
>>
>> On 08/28/13 12:35, Gary Ching-Pang Lin wrote:
>>> Hi,
>>>
>>> I recently updated qemu to 1.6.0 and found OVMF just showed a blank
>>> screen when kvm was enabled. I tried to dump OVMF log with the
>>> following commond but nothing was stored in debug.log.
>>>
>>> qemu-system-x86_64 -s -enable-kvm -bios OVMF.fd -debugcon file:debug.log 
>>> -global isa-debugcon.iobase=0x402
>>>
>>> The kvm trace was recorded with "trace-cmd record -b 20000 -e kvm"
>>> and uploaded to the following link:
>>> https://docs.google.com/file/d/0B9hbtlc_aK_gcGh2TDZLUVlzWWc/edit?usp=sharing
>>>
>>> I found a similar case with kernel < 3.9, but I already upgraded linux
>>> kernel to 3.10.5, so this may be another bug.
>>
>> Well, the usual first response in cases like this is...
>>
>> Can you bisect qemu? :)
> 
> We had a similar report:
> https://bugzilla.novell.com/show_bug.cgi?id=835895

Well that's sorta the same report, considering you and Gary both work
for SUSE, and the Novell BZ seems to imply the build in question was Gary's:

> qemu 1.6.0 fails to run the tianocore firmware
> (home:gary_lin:UEFI/OVMF) properly. This worked with previous qemu
        ^^^^^^^^
> versions:

:)

> 
> git-bisect said:
> 235e8982ad393e5611cb892df54881c872eea9e1 is the first bad commit
> commit 235e8982ad393e5611cb892df54881c872eea9e1
> Author: Jordan Justen <address@hidden>
> Date:   Wed May 29 01:27:26 2013 -0700
> 
>     kvm: support using KVM_MEM_READONLY flag for regions
> 
>     For readonly memory regions and rom devices in romd_mode,
>     we make use of the KVM_MEM_READONLY. A slot that uses
>     KVM_MEM_READONLY can be read from and code can execute from the
>     region, but writes will exit to qemu.
> 
>     For rom devices with !romd_mode, we force the slot to be
>     removed so reads or writes to the region will exit to qemu.
>     (Note that a memory region in this state is not executable
>     within kvm.)
> 
>     v7:
>      * Update for readable => romd_mode rename (5f9a5ea1)
> 
>     Signed-off-by: Jordan Justen <address@hidden>
>     Reviewed-by: Xiao Guangrong <address@hidden> (v4)
>     Reviewed-by: Paolo Bonzini <address@hidden> (v5)
>     Message-id: address@hidden
>     Signed-off-by: Anthony Liguori <address@hidden>
> 
> 
> Any hints or patches welcome. :)

Hm. LP 1212402 <https://bugs.launchpad.net/qemu/+bug/1212402> probably
concerns the "similar case with kernel < 3.9" mentioned by Gary, and is
likely not revelant here.


Gary & Ludwig, can you confirm that your OVMF build includes SVN r14494?

Author: Jordan Justen <address@hidden>
Date:   Thu Jul 18 22:51:27 2013 +0000

    OvmfPkg/Sec: Build identity mapped pages in RAM for X64

    This is based on MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c.

    Previously we would run using page tables built into the
    firmware device.

    If a flash memory is available, it is unsafe for the page
    tables to be stored in memory since the processor may try
    to write to the page table data structures.

    Additionally, when KVM ROM support is enabled for the
    firmware device, then PEI fails to boot when the page
    tables are in the firmware device.

Thanks
Laszlo