much appreciate! :)
At 2018-12-21 14:33:08, "Paolo Bonzini" <pbonz...@redhat.com> wrote: >> 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
