Avi Kivity wrote: > Dong, Eddie wrote: >>>>> If migration happens while rip is in the hypercall page, and if >>>>> the >>>>> >>>>> >>>> I didn't quit catch here. The source VM vCPU is in Qemu migration >>>> part, The target VM VCPU is always waiting for migration >>>> data/command. If you mean SMP case, all target VCPUs are in waiting >>>> for data/cmd, and I assume source VCPUs are all in Qemu known >>>> state, not? >>>> >>>> >>>> >>>> >>> I'm talking about the guest rip. The guest is not aware of the >>> migration. >>> >>> Suppose that on the last copy that the guest rip is >>> (hypercall_page_virt + 3). This address might be in the middle of >>> some instruction on the hypercall page on the target machine. You >>> need to fix up rip and >>> >> >> This depends on how the hypercall page instruction is generated. >> In Xen's construction, the code in hypercall page is exactly same >> between SVM & VMX except the VMCALL/VMMCALL instruction itself. >> >> > > If you make the assumption that the hypercall is a single 3-byte
Mmm, I am not and actually it doesn't care what opcode is used and how long it is. We need to assume the pre-instructions and post instructions are same, and it is totally in VMM plate. Well, using #UD to emulate cross-architecture VMCALL/VMMCALL need to assume the opcode won't be used in other architecture. > instruction, then you might as well patch it directly. Of course it > depends on Intel and AMD not reusing each other's opcodes. Besides the opcode concern and potential bug like Eric & Sheng fixed, the performance of using #UD method is worse than using hypercall page. thx,eddie ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
