On Tue, 2008-05-13 at 22:56 -0400, Vivek Goyal wrote: [...] > > > > > Last time I tried the patches (V9) and kexec jump did not work for me. I > > > was not getting timer interrupts in second kernel. Then I had to put > > > LAPIC and IOAPIC in legacy mode and then at one way jump started working. > > > I am not sure how the next kernel boots for you without putting APICs > > > in legacy mode. (Yet to make returning back to original kernel work > > > using V9). > > > > Can normal kexec (without kexec jump) works without putting LAPIC and > > IOAPIC in legacy mode? Does this mean we should put LAPIC and IOAPIC > > into legacy mode before kexec and restore them after? > > > > We do put LAPIC and IOAPIC in legacy mode in normal kexec. Look at > disable_IO_APIC() in native_machine_shutdown(). So I think we shall > have to do the same thing in kexec jump code too. OK. I will look at this. > I went through above mail thread again where we were discussing what all > information need to be passed between kernels. > > Last time we enumerated three things. > > - kernel entry/re-entry point for switch between kernels. > - backup pages map for core filtering > - Probably ELF core notes for saving hibernated image. > > I think if we just implement the functionality so that one can switch > back and forth between kernels (no hibernated image saving),then we probably > need to pass around only kernel entry/re-entry point and nothing else and in > your patches I think you are already doing using %edi. Yes. > So, IMHO, for first simple implementation, we don't have to pass around > any data between kernels except entry point. (Please correct me if I am > wrong). Lets get that implementation in first and then we can get rest > of the pieces in place. Yes. Kernel entry/re-entry point is the only information need to be communicated between kernels for just switching between them. So we can focus on kexec jump patch firstly. Best Regards, Huang Ying
