Re: [Qemu-devel] kvm control qemu-system-aarch64 state

[Christoffer Dall]

On Wed, Feb 05, 2014 at 10:36:42AM +0100, Claudio Fontana wrote:
> On 4 February 2014 20:40, Christoffer Dall <address@hidden> wrote:
> > On Tue, Feb 04, 2014 at 04:52:08PM +0000, Peter Maydell wrote:
> >> On 4 February 2014 16:37, Claudio Fontana <address@hidden> wrote:
> >> > On 4 February 2014 16:39, Peter Maydell <address@hidden> wrote:
> >> >> On 4 February 2014 15:36, Claudio Fontana <address@hidden> wrote:
> >> >> > I just wanted to ask what is the current state of kvm control for
> >> >> > qemu-system-aarch64.
> >> >> > I tried latest mainline but I think it's not all there yet (it 
> >> >> > complains
> >> >> > about missing cpu when I use -M virt and -cpu host, so I suspect some 
> >> >> > of VOS
> >> >> > patches are still missing).
> >> >> >
> >> >> > Is your aarch64-kvm still the one branch to look at?
> >> >>
> >> >> Nope, this should all work in mainline. If it doesn't it's
> >> >> worth investigating what exactly is going wrong.
> >> >>
> >> >> (Sanity check, you did pass -enable-kvm, right? If you don't
> >> >> then QEMU will complain about "-cpu host", because that
> >> >> only exists if KVM is enabled.)
> >>
> >> > I tried both, without -enable-kvm I get the complaint about "-cpu
> >> > host" as you mention,
> >> > but with -enable-kvm and the latest kernel I get:
> >> >
> >> >
> >> > [ 8489.895747] BUG: Bad page state in process qemu-system-aar  pfn:0a5cd
> >> > [ 8489.895816] page:fffffdfc002444d8 count:-1 mapcount:0 mapping:
> >> >     (null) index:0x0
> >> > [ 8489.895870] page flags: 0x0()
> >> > [ 8489.895916] page dumped because: nonzero _count
> >> > [ 8489.895957] Modules linked in:
> >> > [ 8489.896030] CPU: 0 PID: 3031 Comm: qemu-system-aar Tainted: G    B
> >> >       3.13.0cla-09218-g0e47c96-dirty #2
> >> > [ 8489.896085] Call trace:
> >> > [ 8489.896154] [<fffffe0000095744>] dump_backtrace+0x0/0x12c
> >> > [ 8489.896231] [<fffffe0000095884>] show_stack+0x14/0x1c
> >> > [ 8489.896307] [<fffffe00003db58c>] dump_stack+0x70/0x8c
> >> > [ 8489.896378] [<fffffe00001210d8>] bad_page+0xe8/0x134
> >> > [ 8489.896453] [<fffffe0000121740>] get_page_from_freelist+0x500/0x608
> >> > [ 8489.896532] [<fffffe00001220d0>] __alloc_pages_nodemask+0x110/0x7ec
> >> > [ 8489.896619] [<fffffe000013ce50>] handle_mm_fault+0x760/0x980
> >> > [ 8489.896704] [<fffffe000009a0cc>] do_page_fault+0x228/0x378
> >> > [ 8489.896773] [<fffffe0000090104>] do_mem_abort+0x3c/0x9c
> >> > [ 8489.896833] Exception stack(0xfffffe0020247e30 to 0xfffffe0020247f50)
> >> > [ 8489.896918] 7e20:                                     00000001
> >> > 00000000 aa8505b0 000003ff
> >> > [ 8489.897030] 7e40: ffffffff ffffffff aa785a84 000003ff 00000000
> >> > 00000000 0015e5a8 fffffe00
> >> > [ 8489.897142] 7e60: 20247e70 fffffe00 000c2e48 fffffe00 20247ea0
> >> > fffffe00 00095490 fffffe00
> >> > [ 8489.897254] 7e80: 20244000 fffffe00 00000000 00000000 ffffffff
> >> > ffffffff aa86f118 000003ff
> >> > [ 8489.897366] 7ea0: fea46360 000003ff 0009288c fffffe00 fea46580
> >> > 000003ff fea463e0 000003ff
> >> > [ 8489.897476] 7ec0: fea46360 000003ff 000927ec fffffe00 00f3f710
> >> > 00000000 00012e61 00000000
> >> > [ 8489.897584] 7ee0: 00000000 00000000 00f4d1a0 00000000 0000da91
> >> > 00000000 00000001 00000000
> >> > [ 8489.897694] 7f00: 0000000d 00000000 0000036a 00000000 7f7f7f7f
> >> > 7f7f7f7f 00680ca8 00000000
> >> > [ 8489.897800] 7f20: 0000006d 00000000 00000020 00000000 00000078
> >> > 00000000 00000080 00000000
> >> > [ 8489.897884] 7f40: 006812b0 00000000 aa852598 000003ff
> >>
> > Ugh,
> >
> > can you let me know the kernel version, qemu version, and exact command
> > line you are using?
> >
> > -Christoffer
> 
> I think I just configured it wrongly, now it works:
> 
> kernel is mainline from Jan 28, commit 
> 0e47c969c65e213421450c31043353ebe3c67e0c
> qemu is mainline from Jan 31, commit 97374ce538883af677fd94803b71df2d55a9a4de
> 
> I had the kernel configured with CONFIG_ARM64_64K_PAGES
> and CONFIG_TRANSPARENT_HUGEPAGE.
> 
> Disabling those fixed it for me.
> 
That definitely sounds like a bug, I'll look into it.

Thanks for reporting.

-Christoffer