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

[Bruce Rogers]

 >>> On 8/29/2013 at 02:23 AM, Gary Ching-Pang Lin <address@hidden> wrote: 
> On Wed, Aug 28, 2013 at 02:55:26PM +0200, Andreas Färber wrote:
>> Am 28.08.2013 14:10, schrieb 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:
>> > 
>> > :)
>> 
>> Different reporters, so who knows if the setups are the same. ;)
>> 
>> >> 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 devi
ce, then PEI fails to boot when the page
>> >     tables are in the firmware device.
>> 
>> https://build.opensuse.org/package/show/Virtualization/OVMF
>> is at r14547 and that one works for me.
>> 
>> Gary/Ludwig, can you confirm that this is resolved?
>>
> I still got the black screen even with OVMF r14547 or r14608. I also
> tried kernel 3.10.9 and 3.11-rc7, but no luck.
> 
> Reverting the KVM_MEM_READONLY patch works for me, but the OVMF patch
> somehow didn't work.
> 
> Thanks,
> 
> Gary Lin

I tried this out, and I get the black screen as well when ept=n, but it boots
successfully to the efi shell when ept=y.

Gary, what does 'cat /sys/module/kvm_intel/parameters/ept' report on your
failing machine?

Bruce