From 1d48b90c2119ac59fdc04e16200b9502b8d835f5 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Thu, 9 Jan 2025 09:39:34 -0500 Subject: [PATCH] Choose -cpu max by default You must set -cpu to something on RHEL 10 with TCG since the kernel on that platform now requires x86_64-v3. Choosing a good default is difficult. Use -cpu max as that was supposed to fix this, although in practice it doesn't work very reliably. This is likely a temporary solution. More reliable/permanent solutions include: - Allowing the user to set the default CPU at configure time. - A large case statement that tries to get it right for every possible combination of platform/architecture/KVM/... - Fixing -cpu max in qemu --- src/qemu-sanity-check.in | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/src/qemu-sanity-check.in b/src/qemu-sanity-check.in index 0c96485..d8962d4 100644 --- a/src/qemu-sanity-check.in +++ b/src/qemu-sanity-check.in @@ -28,18 +28,16 @@ canonical_arch="$(uname -m | sed 's/i[456]86/i386/')" verbose=no timeout=10m accel=kvm:tcg -cpu= memory=768 console=ttyS0 machine= -# Both libguestfs and virt-manager choose cpu=host when we think that -# KVM is available, and default otherwise. Although testing for KVM -# is hairy, I found that on aarch64 it can fail unless we choose -# cpu=host for KVM. -if test -r /dev/kvm; then - cpu=host -fi +# Choosing a good CPU default is a minefield. Ideally '-cpu max' is +# supposed to choose the best CPU type, but it notably fails on RISC-V +# (not supported) and x86_64+TCG (enables LA57 which TCG does not +# emulate). Default minimum CPU will not work on RHEL 10, since that +# requires at least x86_64-v3. +cpu=max # Default machine and CPU type depends on arch. You can override this # using -m|--machine and --cpu options. @@ -49,7 +47,6 @@ case "$canonical_arch" in machine=virt ;; aarch*) console=ttyAMA0 - if [ "$cpu" = "" ]; then cpu=cortex-a57; fi machine=virt ;; s390*) console=ttysclp0 ;; -- 1.8.3.1