On 2011-09-11 09:11, Avi Kivity wrote: > On 09/10/2011 11:41 AM, ya su wrote: >> 0x80637b85: testl $0x1000, 0xfffe0300 >> 0x80637b8f: jne 0x80637b85 >> 0x80637b91: mov %ecx, 0xfffe0300 >> 0x80637b97: testl $0x1000, 0xfffe0300 >> 0x80637ba1: jne 0x80637b97 >> >> I wonder why testl operation will also cause a ICR write, from the >> asm code, there should only issue one IPI, but from trace-cmd, it >> issued 3 IPI, is there something wrong? > > It's a bug in test insn emulation, coincidentally I wrote a patch to fix > it yesterday, not imagining that it actually happens in practice. > >> Is it also possible to optimize ICR write emulation, from the >> result, winxp vm will produce a lot of ICR writes >> > > Unfortunately not. I'm just hoping we'll see hardware-assisted APIC, ideally also IOAPIC virtualization soon. Jan
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