> scenario 1: did the tcg translation need to be done in this case now > that the host and target arch is the same? or let the kvm emulation > the system wit the original instructions with out the TCG > translation
TCG is turned off when KVM is enabled. The code for TCG does not run at all. > scenario 2: the pre condition is same with scenario 1 except the kvm > is disable？ so ,in this scenario, the TCG must be used in order to > the pure software emulation without acceleration? Correct. In this case KVM is turned off. The capabilities of the emulated CPU will _not_ be what you have in your host processor, but rather what QEMU implements. For example, you will get no AVX. > scenario 3: in this scenario, the host and target arch is not the > same, so how to use the "kvm mechainsim" in this case? so the > instructions feed to the kvm module to run must be translated By TCG > module? right? KVM cannot be used in this case; KVM is only enabled when the host and the target are the same. Paolo On 21/12/18 02:57, tugouxp wrote: > hi folks: > i am very puzzled about the relationship between "target cpu instruction" > translated to host instructions through TCG module and the "kvm" > acceleration" mode. > > > think about three scenario of emulation: > scenario 1, 2 and 3 as follows: > > 1. target cpu: x86_64, > host cpu: x84_64, > emulation OS: ubuntu_desktop_amd64.iso > kvm: enabled. > > > 2. target cpu: x86_64, > > host cpu: x84_64, > > emulation OS: ubuntu_desktop_amd64.iso > kvm: disabled. > > > 3. target cpu x86_64, > host cpu: armv8 > emulationOS: ubuntu_desktop_amd64.iso > kvm: enabled
