[SeaBIOS] [Qemu-devel] [PATCH] SeaBios: Fix reset procedure reentrancy problem on qemu-kvm platform

[Xulei (Stone)]

Hi, Kevin,
Can you tell how to reset/reboot this VM, if it goes to the handle_hwpic1()
on its booting procedure? I mean, usually, SeaBIOS would not go to 
handle_hwpic routine. But in my test case, SeaBIOS calls handle_hwpic when
KVM injects a #UD expcetion (not irq) and  SeaBIOS will loop to handle this
if KVM persistently injects exception.
 
Now, i just wish to reset/reboot this VM if it is fall into handle_hwpic. I
tried follwing patch and it seems not work. What can i do to force reset/reboot? 

@@ -7,10 +7,11 @@
  #include "biosvar.h" // SET_IVT
  #include "config.h" // CONFIG_*
  #include "output.h" // dprintf
  #include "pic.h" // pic_*
+ #include "hw/ps2port.h"
 
 u16
 pic_irqmask_read(void)
 {
     if (!CONFIG_HARDWARE_IRQ)
@@ -103,10 +104,11 @@ pic_isr2_read(void)
 void VISIBLE16
 handle_hwpic1(struct bregs *regs)
 {
     dprintf(DEBUG_ISR_hwpic1, "handle_hwpic1 irq=%x\n", pic_isr1_read());
     pic_eoi1();
+	 i8042_reboot();
 }

useful information:
kmod ftrace:
<...>-31509 [035] 154753.180077: kvm_exit: reason EXCEPTION_NMI rip 0x3 info 0 80000306
<...>-31509 [035] 154753.180077: kvm_emulate_insn: 0:3:f0 53 (real)
<...>-31509 [035] 154753.180077: kvm_inj_exception: #UD (0x0)
<...>-31509 [035] 154753.180077: kvm_entry: vcpu 0

bad SeaBIOS log:
[2015-12-17 12:37:30] In 32bit resume
[2015-12-17 12:37:30] =====Attempting a hard reboot====
[2015-12-17 12:37:30] SeaBIOS (version rel-1.8.1-0-g4adadbd-20151217_104405-linux-emBwNn)
[2015-12-17 12:37:30] No Xen hypervisor found.
[2015-12-17 12:37:30] Running on QEMU (i440fx)
[2015-12-17 12:37:30] Running on KVM
[2015-12-17 12:37:30] RamSize: 0x80000000 [cmos]
[2015-12-17 12:37:30] Relocating init from 0x000db230 to 0x7ffad360 (size 76768)
[2015-12-17 12:37:30] Found QEMU fw_cfg
[2015-12-17 12:37:30] RamBlock: addr 0x0000000000000000 len 0x0000000080000000 [e820]
[2015-12-17 12:37:30] Moving pm_base to 0x600
[2015-12-17 12:37:30] boot order:
[2015-12-17 12:37:30] 1: /pci at i0cf8/ide at 1,1/drive at 0/disk at 0
[2015-12-17 12:37:30] 2: HALT
[2015-12-17 12:37:30] maininit
[2015-12-17 12:37:30] platform_hardware_setup
[2015-12-17 12:37:30] init pic
[2015-12-17 12:37:30] pic_setup
[2015-12-17 12:37:30] pic_reset
[2015-12-17 12:37:30] enable_hwirq
[2015-12-17 12:37:30] CPU Mhz=3304
[2015-12-17 12:37:30] enable_hwirq
[2015-12-17 12:37:30] enable_hwirq
[2015-12-17 12:37:30] === PCI bus & bridge init ===
[2015-12-17 12:37:30] PCI: pci_bios_init_bus_rec bus = 0x0
[2015-12-17 12:37:30] === PCI device probing ===
[2015-12-17 12:37:30] Found 6 PCI devices (max PCI bus is 00)
[2015-12-17 12:37:30] === PCI new allocation pass #1 ===
[2015-12-17 12:37:30] PCI: check devices
[2015-12-17 12:37:30] === PCI new allocation pass #2 ===
[2015-12-17 12:37:30] PCI: IO: c000 - c02f
[2015-12-17 12:37:30] PCI: 32: 0000000080000000 - 00000000fec00000
[2015-12-17 12:37:30] PCI: map device bdf=00:01.2  bar 4, addr 0000c000, size 00000020 [io]
[2015-12-17 12:37:30] PCI: map device bdf=00:01.1  bar 4, addr 0000c020, size 00000010 [io]
[2015-12-17 12:37:30] PCI: map device bdf=00:02.0  bar 6, addr febe0000, size 00010000 [mem]
[2015-12-17 12:37:30] PCI: map device bdf=00:02.0  bar 1, addr febf0000, size 00001000 [mem]
[2015-12-17 12:37:30] PCI: map device bdf=00:02.0  bar 0, addr fc000000, size 02000000 [prefmem]
[2015-12-17 12:37:30] PCI: init bdf=00:00.0 id=8086:1237
[2015-12-17 12:37:30] PCI: init bdf=00:01.0 id=8086:7000
[2015-12-17 12:37:30] PIIX3/PIIX4 init: elcr=00 0c
[2015-12-17 12:37:30] PCI: init bdf=00:01.1 id=8086:7010
[2015-12-17 12:37:30] PCI: init bdf=00:01.2 id=8086:7020
[2015-12-17 12:37:30] PCI: init bdf=00:01.3 id=8086:7113
[2015-12-17 12:37:30] Using pmtimer, ioport 0x608
[2015-12-17 12:37:30] PCI: init bdf=00:02.0 id=1013:00b8
[2015-12-17 12:37:30] PCI: Using 00:02.0 for primary VGA
[2015-12-17 12:37:30] handle_hshamanpnd:dl leae_p_sismcmp_p:i: d a=ap3               <<======= everytime stuck, AP setup log seems abnormal!
[2015-12-17 12:37:30] ièf[cf_^ifd_=f3
[2015-12-17 12:37:30] èf[f^f_f]fÃÍ^XË<90>Found 4 cpu(s) max supported 4 cpu(s)
[2015-12-17 12:37:30] Copying PIR from 0x7ffbea18 to 0x000f5700
[2015-12-17 12:37:30] Copying MPTABLE from 0x00006e30/7ffa42c0 to 0x000f55e0
[2015-12-17 12:37:30] Copying SMBIOS entry point from 0x00006e11 to 0x000f55c0
[2015-12-17 12:37:31] Scan for VGA option rom
[2015-12-17 12:37:31] Running option rom at c000:0003
[2015-12-17 12:37:31] Start SeaVGABIOS (version rel-1.8.1-0-g4adadbd-20150316_085902-nilsson.home.kraxel.org)
[2015-12-17 12:37:31] enter vga_post:
[2015-12-17 12:37:31]    a=00000010  b=0000ffff  c=00000000  d=0000ffff ds=0000 es=f000 ss=0000
[2015-12-17 12:37:31]   si=00000000 di=000057e0 bp=00000000 sp=00006dbe cs=f000 ip=d1fb  f=0000
[2015-12-17 12:37:31] cirrus init
[2015-12-17 12:37:31] cirrus init 2
[2015-12-17 12:37:31] Attempting to allocate VGA stack via pmm call to f000:d2a0   <<====== here stuck, loop handle PIC irq0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
[2015-12-17 12:37:35] handle_hwpic1 irq=0
... always hanle_hwpic1 irq=0, never ends anymore...


>> -----Original Message-----
>> From: Kevin O'Connor [mailto:kevin at koconnor.net]
>> Sent: Tuesday, December 22, 2015 2:47 AM
>> To: Gonglei (Arei)
>> Cc: Xulei (Stone); Paolo Bonzini; qemu-devel; seabios at seabios.org;
>> Huangweidong (C); kvm at vger.kernel.org; Radim Krcmar
>> Subject: Re: [Qemu-devel] [PATCH] SeaBios: Fix reset procedure reentrancy
>> problem on qemu-kvm platform
>>
>> On Mon, Dec 21, 2015 at 09:41:32AM +0000, Gonglei (Arei) wrote:
>> > When the gurb of OS is booting, then the softirq and C function
>> > send_disk_op() may use extra stack of SeaBIOS. If we inject a NMI,
>> > romlayout.S: irqentry_extrastack is invoked, and the extra stack will
>> > be used again. And the stack of first calling will be broken, so that the
>> SeaBIOS stuck.
>> >
>> > You can easily reproduce the problem.
>> >
>> > 1. start on guest
>> > 2. reset the guest
>> > 3. inject a NMI when the guest show the grub surface 4. then the guest
>> > stuck
>>
>> Does the SeaBIOS patch below help? 
>
>Sorry, it doesn't work. What's worse is we cannot stop SeaBIOS stuck by
>Setting "CONFIG_ENTRY_EXTRASTACK=n" after applying this patch.
>
>
>> I'm not familiar with how to "inject a
>> NMI" - can you describe the process in more detail?
>>
>
>1. Qemu Command line:
>
>#: /home/qemu/x86_64-softmmu/qemu-system-x86_64 -enable-kvm -m 4096 -smp 8 -name suse -vnc 0.0.0.0:10 \
>-device virtio-scsi-pci,id=scsi0 -drive file=/home/suse11_sp3_32_2,if=none,id=drive-scsi0-0-0-0,format=raw,cache=none,aio=native \
>-device scsi-hd,bus=scsi0.0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0 \
>-chardev file,id=seabios,path=/home/seabios.log -device isa-debugcon,iobase=0x402,chardev=seabios \
>-monitor stdio -qmp unix:/tmp/qmp,server,nowait
>
>2. Inject a NMI by QMP:
>
>#: /home/qemu/scripts/qmp # ./qmp-shell /tmp/qmp
>Welcome to the QMP low-level shell!
>Connected to QEMU 2.5.0
>
>(QEMU) system_reset
>{"return": {}}
>(QEMU) inject-nmi 
>{"return": {}}
>(QEMU) inject-nmi
>{"return": {}}
>
>
>Regards,
>-Gonglei
>
>> -Kevin
>>
>>
>> --- a/src/romlayout.S
>> +++ b/src/romlayout.S
>> @@ -548,7 +548,9 @@ entry_post:
>>          ENTRY_INTO32 _cfunc32flat_handle_post   // Normal entry point
>>
>>          ORG 0xe2c3
>> -        IRQ_ENTRY 02
>> +        .global entry_02
>> +entry_02:
>> +        ENTRY handle_02  // NMI handler does not switch onto extra
>> +stack
>>
>>          ORG 0xe3fe
>>          .global entry_13_official