mirror of
https://gitlab.com/qemu-project/qemu.git
synced 2026-10-28 14:04:39 +08:00
Peter Maydell
05c14358d5
Currently when using KVM on Arm, the normal thing is to use either the 'host' or 'max' CPU types, both of which give the guest the same CPU as the host. We also for legacy reasons allow 'cortex-a53' and 'cortex-a57' CPU types, which will only work when the host CPU is exactly that matching CPU. This is because the original idea of the KVM ABI was that userspace would request a particular CPU type by setting the target field in the KVM_ARM_VCPU_INIT ioctl to an appropriate KVM_ARM_TARGET_* constant. However, it quickly became clear that this was a bad idea, and now everything uses KVM_ARM_TARGET_GENERIC_V8; the tiny number of existing CPU-specific target values behave identically to GENERIC_V8 except that they will only work if the host CPU matches them. Future support for "show the KVM guest a CPU type that's not identical to the host" is going to work by telling it different ID register values. Real Cortex-A53 and A57 CPUs are now all over a decade old and not in widespread use. Deprecate the ability to use '-cpu cortex-a53' and '-cpu cortex-a57' with KVM, to get rid of this odd legacy corner and open up the opportunity in future to support named CPU types via ID register settings if we want that. For any situation where the cortex-a53 and cortex-a57 CPU types currently work with KVM, '-cpu host' or '-cpu max' will have identical behaviour. (Though note that if you are using "KVM, but fall back to TCG" then the fallback under TCG will be different.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Khushit Shah <khushit.shah@nutanix.com> Message-id: 20261013105147.1070641-1-peter.maydell@linaro.org