> -----Original Message----- > From: Kevin O'Connor [mailto:kevin@xxxxxxxxxxxx] > Sent: Tuesday, December 22, 2015 11:51 PM > To: Gonglei (Arei) > Cc: Xulei (Stone); Paolo Bonzini; qemu-devel; seabios@xxxxxxxxxxx; > Huangweidong (C); kvm@xxxxxxxxxxxxxxx; Radim Krcmar > Subject: Re: [Qemu-devel] [PATCH] SeaBios: Fix reset procedure reentrancy > problem on qemu-kvm platform > > On Tue, Dec 22, 2015 at 02:14:12AM +0000, Gonglei (Arei) wrote: > > > From: Kevin O'Connor [mailto:kevin@xxxxxxxxxxxx] > > > Sent: Tuesday, December 22, 2015 2:47 AM > > > To: Gonglei (Arei) > > > Cc: Xulei (Stone); Paolo Bonzini; qemu-devel; seabios@xxxxxxxxxxx; > > > Huangweidong (C); kvm@xxxxxxxxxxxxxxx; 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. > > Oops, can you try with the patch below instead? > It works now. Thanks! But do we need to check other possible situations that maybe cause *extra stack* broken or overridden? > > > 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": {}} > > > > I tried a few simple tests but was not able to reproduce. > After reset the guest, then you inject an NMI when you see the grub surface ASAP. Kevin, I sent you a picture in private. :) Regards, -Gonglei > -Kevin > > > --- a/src/romlayout.S > +++ b/src/romlayout.S > @@ -548,7 +548,10 @@ 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 > + iretw > > ORG 0xe3fe > .global entry_13_official -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
