On 2018-10-05 23:12, Paolo Bonzini wrote: > On 05/10/2018 16:22, Peter Maydell wrote: >> On 5 October 2018 at 15:13, Thomas Huth <th...@redhat.com> wrote: >>> When compiling with "--disable-tcg", we currently still use "tcg" >>> as default accelerator. "kvm" should be used in this case instead. >> >> This part is non-controversial and makes good sense. > > Though it probably should be extended to "whpx" and "hvf" (probably > "xen" too if !CONFIG_KVM).
Sure, I was just unsure whether anybody has ever tried to compile with --disable-tcg and --disable-kvm and use one of those accelerators instead? Does it work? >>> Also, some downstream distros provide QEMU binaries which have "kvm" >>> in their names (e.g. "qemu-kvm" on RHEL or "kvm" on Ubuntu) that use >>> KVM by default - and some users might want to do something similar >>> with upstream binaries, too. Accomodate them by using "kvm:tcg" as >>> default when we detect such a binary name. >> >> This part is much riskier and less clearly a good plan -- >> do we really want our behaviour to vary based on the name >> of the executable? Distros who want that sort of qemu-kvm >> wrapper generally are providing it already (the Ubuntu one >> is a 2-line shell script). > > I think it makes sense. At least RHEL has qemu-kvm but no > qemu-system-x86_64, so it has a non-upstream patch to change the > accelerator; for other distros there are two benefits: > > 1) now: they could switch to a symlink Right, I think it's a good idea to avoid wrapper scripts - there is less chance to get things wrong in this case. Thomas
