Re: [Libguestfs] [PATCH] always 'max' for the appliance CPU model on all targes except ppc

On Wed, May 25, 2022 at 05:13:53PM +0100, Peter Maydell wrote: > On Wed, 25 May 2022 at 16:07, Laszlo Ersek <lersek(a)redhat.com&gt; wrote: > > > > + Drew & Peter > > > > On 05/25/22 15:30, Daniel P. Berrangé wrote: > > - The patch seems to do what it says in the commit message. > > > > - QEMU commit bab52d4bba3f ("target/arm: Add "-cpu max" support", > > 2018-03-09) confirms what the commit message says, about both TCG and > > KVM. > > > > - To smoke-test the TCG-related change, I've edited a long-term TCG > > aarch64 libvirt domain of mine, replacing "cortex-a57" with "max". > > Both edk2 and the Linux guest continued working. So I guess the TCG > > change is OK. > > One thing to note here is that if you are using: > * TCG -cpu max > * 'virt' with no named version or with 'virt-7.0' or later > * a Linux kernel version prior to v5.12 > then a bug in Linux means it won't boot. (This is because of > the LPA2 CPU feature which TCG -cpu max now emulates; older > kernels were buggy and won't boot on an LPA2 CPU, including > a real hardware one.) Is this related at all to the 5-level page tables (la57) failure with TCG and -cpu max? https://gitlab.com/qemu-project/qemu/-/issues/1023