[SeaBIOS] Qemu-kvm VM halt at allocate VGA stack when continuously reset VM

Kevin O'Connor kevin at koconnor.net
Thu Dec 17 23:28:52 CET 2015

On Thu, Dec 17, 2015 at 05:28:23AM +0000, Xulei (Stone) wrote:
> 1. This problem seems have relations with PIC irq0 and host CPU feature:
> On one of my host, this problem never happens while on another, it's 
> very easy to happen (both of hosts have the same kmod,qemu,libvirt and
> SeaBIOS, SeaVGABIOS, except for the CPU feature).
> 2. SeaBIOS log tells me once VM halts at allocate VGA stack, it also has something
> wrong printing handle_smp log. 
> 3. If i disconfig CONFIG_VGA_ALLOCATE_EXTRA_STACK, the VM will halt at Grub stage,
> and SeaVGABIOS log stop at printing "set VGA mode 114", then BIOS will loop handle_pwhic1.
> For now, i guess whether if SeaBIOS can not handle the hardware interrupt correctly
> when a host CPU has some advanced feature (x2apic? avx? xsave? tsc-deadline?). 

At first glance, this sounds like there is a level based interrupt
enabled somewhere and after a reset the apic isn't disabled.  It
doesn't seem like a seabios issue - as seabios doesn't really use the
apic.  I'd raise it on the qemu list.


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