topic: Re: kvm running on core1 wants guest os on core2 to execute a pre-defined program On Sun, Feb 17, 2013 at 02:46:28AM +0000, zhangzhi wrote: > I have been studying some stuff about KVM and sincerely hope that > someone is willing to reply to this mail. > As we know, If physical NIC interrupt is received on physical CPU 0 > which is in root mode and the hypervisor determines that this is a > network packet targeted to the emulated NIC for a VM at the same time > this VM is running a user program in guest mode on physical CPU 1. > My question is: > At this time can hypervisor running on CPU 0 *actively* interrupt VM > and make it run the corresponding interrupt handler to handle the > incoming network data packet? CPU 1 which is running a user program is > not supposed to vm-exit considering the performance effect, so I can > not use the inter-processor > interrupt(IPI) to cause the CPU1 to leave guest mode and exit to the hypervisor. > On Sun, Feb 17, 2013 at 20:06:18PM +0000, Gleb wrote: >>With current generation of CPUs you will have to use IPI to make CPU1 vmexit and inject interrupt on the next vmentry. Future CPU will allow to >>inject interrupt into a running guest without vmexit. On Intel this is called "posted interrupts". >> >> Thank you for your prompt reply. According to what you've said, it seems impossible to make CPU1 run the corresponding interrupt handler without vm-exit. I have an idea like this: CPU0 send a message to i/o apic after configuring i/o apic and the message is mainly about the interrupt vector of emulated NIC. After that, the i/o apic will go around hypervisor and send the corresponding interrupt request directly to target CPU1 , considering that guest os itself owns the NIC device. Is it possible? Thanks! henry -- 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
