On 2 March 2018 at 12:26, Auger Eric <eric.auger@xxxxxxxxxx> wrote: > Hi Marc, > On 02/03/18 12:11, Marc Zyngier wrote: >> On Fri, 02 Mar 2018 10:44:48 +0000, >> Auger Eric wrote: >>> I understand the get/set is called as part of the migration process. >>> So my understanding is the benefit of this series is migration fails in >>> those cases: >>> >>>> =0.2 source -> 0.1 destination >>> 0.1 source -> >=0.2 destination >> >> It also fails in the case where you migrate a 1.0 guest to something >> that cannot support it. > > That's because on the destination, the number of regs is less than on > source, right? I think it fails because the KVM_REG_ARM_PSCI_VERSION register will be in the migration state but not in the destination's list of registers: the code in QEMU's target/arm/machine.c:cpu_post_load() function that checks "register in their list but not ours: fail migration" will catch this. That also means that we will fail migration from a new kernel where we've specifically asked for PSCI 0.2 to an old PSCI-0.2-only kernel (because the KVM_REG_ARM_PSCI_VERSION reg will appear in the migration stream even if its value is the one value that matches the old kernel behaviour). I don't know if we care about that. thanks -- PMM _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
