Re: regression bisected; KVM: entry failed, hardware error 0x80000021

From: Chen, Tiejun
Date: Thu Dec 25 2014 - 20:44:51 EST


On 2014/12/25 18:52, Jamie Heilman wrote:
Chen, Tiejun wrote:
On 2014/12/24 19:02, Jamie Heilman wrote:
Chen, Tiejun wrote:
On 2014/12/23 15:26, Jamie Heilman wrote:
Chen, Tiejun wrote:
On 2014/12/23 9:50, Chen, Tiejun wrote:
On 2014/12/22 17:23, Jamie Heilman wrote:
KVM internal error. Suberror: 1
emulation failure
EAX=000de494 EBX=00000000 ECX=00000000 EDX=00000cfd
ESI=00000059 EDI=00000000 EBP=00000000 ESP=00006fb4
EIP=000f15c1 EFL=00010016 [----AP-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT= 000f6be8 00000037
IDT= 000f6c26 00000000
CR0=60000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000000
Code=e8 ae fc ff ff 89 f2 a8 10 89 d8 75 0a b9 41 15 ff ff ff d1 <5b>
5e c3 5b 5e e9 76 ff ff ff b0 11 e6 20 e6 a0 b0 08 e6 21 b0 70 e6 a1
b0 04 e6 21 b0 02

FWIW, I get the same thing with 34a1cd60d17 reverted. Maybe there are
two bugs, maybe there's more to this first one. I can repro this

So if my understanding is correct, this is probably another bug. And
especially, I already saw the same log in another thread, "Cleaning up
the KVM clock". Maybe you can continue to `git bisect` to locate that
bad commit.


Looks just now Andy found that commit,
0e60b0799fedc495a5c57dbd669de3c10d72edd2 "kvm: change memslot sorting rule
>from size to GFN", maybe you can try to revert this to try yours again.

That doesn't revert cleanly for me, and I don't have much time to
fiddle with it until the 24th---so checked out the commit before it
(d4ae84a0), applied your patch, built, and yes, everything works fine
at that point. I'll probably have time for another full bisection
later, assuming things aren't ironed out already by then.

3.18.0-rc3-00120-gd4ae84a0 + vmx reorder msr writes patch = OK
3.18.0-rc3-00121-g0e60b07 + vmx reorder msr writes patch = emulation failure

So that certainly points to 0e60b0799fedc495a5c57dbd669de3c10d72edd2
as well.

Could you try this to fix your last error?

Running qemu-system-x86_64 -machine pc,accel=kvm -nodefaults works,
my real (headless) kvm guests work, but this new patch makes running
"qemu-system-x86_64 -machine pc,accel=kvm" fail again, this time with

Are you sure? From my test based on 3.19-rc1 that it owns top commit,

aa39477b5692611b91ac9455ae588738852b3f60

just plus my previous patch, "kvm: x86: vmx: reorder some msr writing"

I already can execute such a command successfully,

qemu-system-x86_64 -machine pc,accel=kvm -m 2048 -smp 2 -hda ubuntu.img

And your log below seems not to relate mem_slot issue we're discussing, I
guess you need to update qemu as well.

Yes, I'm sure.

But I also found my new patch just work out Andy's next case, its really
bringing a new issue in !next case. So I tried to refine that patch again as
follows,

This latest patch (again, after fixing all the whitespace so it actually

Next time I guess I need to post that as a attached file :)

applies), does the trick. Both
"qemu-system-x86_64 -machine pc,accel=kvm" and
"qemu-system-x86_64 -machine pc,accel=kvm -nodefaults" work for me
now without any of the aforementioned warnings from the host.

Sounds great and thanks for your test again.

Tiejun



Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
---
virt/kvm/kvm_main.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f528343..910bc48 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -672,6 +672,7 @@ static void update_memslots(struct kvm_memslots *slots,
WARN_ON(mslots[i].id != id);
if (!new->npages) {
new->base_gfn = 0;
+ new->flags = 0;
if (mslots[i].npages)
slots->used_slots--;
} else {
@@ -688,7 +689,9 @@ static void update_memslots(struct kvm_memslots *slots,
i++;
}
while (i > 0 &&
- new->base_gfn > mslots[i - 1].base_gfn) {
+ ((new->base_gfn > mslots[i - 1].base_gfn) ||
+ (!new->base_gfn &&
+ !mslots[i - 1].base_gfn && !mslots[i - 1].npages))) {
mslots[i] = mslots[i - 1];
slots->id_to_index[mslots[i].id] = i;
i--;



Tiejun

errors in the host to the tune of:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 3901 at arch/x86/kvm/x86.c:6575 kvm_arch_vcpu_ioctl_run+0xd63/0xe5b [kvm]()
Modules linked in: nfsv4 cpufreq_userspace cpufreq_stats cpufreq_powersave cpufreq_ondemand cpufreq_conservative autofs4 fan nfsd auth_rpcgss nfs lockd grace fscache sunrpc bridge stp llc vhost_net tun vhost macvtap macvlan fuse cbc dm_crypt usb_storage snd_hda_codec_analog snd_hda_codec_generic kvm_intel kvm tg3 ptp pps_core sr_mod snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_pcm snd_timer snd sg dcdbas cdrom psmouse soundcore floppy evdev xfs dm_mod raid1 md_mod
CPU: 1 PID: 3901 Comm: qemu-system-x86 Not tainted 3.19.0-rc1-00011-g53262d1-dirty #1
Hardware name: Dell Inc. Precision WorkStation T3400 /0TP412, BIOS A14 04/30/2012
0000000000000000 000000007e052328 ffff8800c25ffcf8 ffffffff813defbe
0000000000000000 0000000000000000 ffff8800c25ffd38 ffffffff8103b517
ffff8800c25ffd28 ffffffffa019bdec ffff8800caf1d000 ffff8800c2774800
Call Trace:
[<ffffffff813defbe>] dump_stack+0x4c/0x6e
[<ffffffff8103b517>] warn_slowpath_common+0x97/0xb1
[<ffffffffa019bdec>] ? kvm_arch_vcpu_ioctl_run+0xd63/0xe5b [kvm]
[<ffffffff8103b60b>] warn_slowpath_null+0x15/0x17
[<ffffffffa019bdec>] kvm_arch_vcpu_ioctl_run+0xd63/0xe5b [kvm]
[<ffffffffa02308b9>] ? vmcs_load+0x20/0x62 [kvm_intel]
[<ffffffffa0231e03>] ? vmx_vcpu_load+0x140/0x16a [kvm_intel]
[<ffffffffa0196ba3>] ? kvm_arch_vcpu_load+0x15c/0x161 [kvm]
[<ffffffffa018d8b1>] kvm_vcpu_ioctl+0x189/0x4bd [kvm]
[<ffffffff8104647a>] ? do_sigtimedwait+0x12f/0x189
[<ffffffff810ea316>] do_vfs_ioctl+0x370/0x436
[<ffffffff810f24f2>] ? __fget+0x67/0x72
[<ffffffff810ea41b>] SyS_ioctl+0x3f/0x5e
[<ffffffff813e34d2>] system_call_fastpath+0x12/0x17
---[ end trace 46abac932fb3b4a1 ]---
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3901 at arch/x86/kvm/x86.c:6575 kvm_arch_vcpu_ioctl_run+0xd63/0xe5b [kvm]()
Modules linked in: nfsv4 cpufreq_userspace cpufreq_stats cpufreq_powersave cpufreq_ondemand cpufreq_conservative autofs4 fan nfsd auth_rpcgss nfs lockd grace fscache sunrpc bridge stp llc vhost_net tun vhost macvtap macvlan fuse cbc dm_crypt usb_storage snd_hda_codec_analog snd_hda_codec_generic kvm_intel kvm tg3 ptp pps_core sr_mod snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_pcm snd_timer snd sg dcdbas cdrom psmouse soundcore floppy evdev xfs dm_mod raid1 md_mod
CPU: 1 PID: 3901 Comm: qemu-system-x86 Tainted: G W 3.19.0-rc1-00011-g53262d1-dirty #1
Hardware name: Dell Inc. Precision WorkStation T3400 /0TP412, BIOS A14 04/30/2012
0000000000000000 000000007e052328 ffff8800c25ffcf8 ffffffff813defbe
0000000000000000 0000000000000000 ffff8800c25ffd38 ffffffff8103b517
ffff8800c25ffd28 ffffffffa019bdec ffff8800caf1d000 ffff8800c2774800
Call Trace:
[<ffffffff813defbe>] dump_stack+0x4c/0x6e
[<ffffffff8103b517>] warn_slowpath_common+0x97/0xb1
[<ffffffffa019bdec>] ? kvm_arch_vcpu_ioctl_run+0xd63/0xe5b [kvm]
[<ffffffff8103b60b>] warn_slowpath_null+0x15/0x17
[<ffffffffa019bdec>] kvm_arch_vcpu_ioctl_run+0xd63/0xe5b [kvm]
[<ffffffffa02308b9>] ? vmcs_load+0x20/0x62 [kvm_intel]
[<ffffffffa0231e03>] ? vmx_vcpu_load+0x140/0x16a [kvm_intel]
[<ffffffffa0196ba3>] ? kvm_arch_vcpu_load+0x15c/0x161 [kvm]
[<ffffffffa018d8b1>] kvm_vcpu_ioctl+0x189/0x4bd [kvm]
[<ffffffff8104647a>] ? do_sigtimedwait+0x12f/0x189
[<ffffffff810ea316>] do_vfs_ioctl+0x370/0x436
[<ffffffff810f24f2>] ? __fget+0x67/0x72
[<ffffffff810ea41b>] SyS_ioctl+0x3f/0x5e
[<ffffffff813e34d2>] system_call_fastpath+0x12/0x17
---[ end trace 46abac932fb3b4a2 ]---

over and over and over ad nauseum, or until I kill the qemu command,
it also eats a core's worth of cpu.

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