On 2015-02-15 14:37, Marc Zyngier wrote: > On Sun, Feb 15 2015 at 8:53:30 am GMT, Jan Kiszka <jan.kiszka@xxxxxx> wrote: >> I'm now throwing trace_printk at my broken KVM. Already found out that I >> get ARM_EXCEPTION_IRQ every few 10 µs. Not seeing any irq_* traces, >> though. Weird. > > This very much looks like a screaming interrupt. At such a rate, no > wonder your VM make much progress. Can you find out which interrupt is > screaming like this? Looking at GICC_HPPIR should help, but you'll have > to map the CPU interface in HYP before being able to access it there. OK... let me figure this out. I had this suspect as well - the host gets a VM exit for each injected guest IRQ? BTW, I also tried with in-kernel GIC disabled (in the kernel config), but I guess that's pointless. Linux seems to be stuck on a non-functional architectural timer then, right? > > Do you have an form of power-management on this system? Just killed every config that has PM for FREQ in its name, but that makes no difference. Jan
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