Il 30/04/2014 03:11, Marcelo Tosatti ha scritto: > On Tue, Apr 29, 2014 at 06:17:17PM -0300, Eduardo Habkost wrote: >> KVM never supported the MONITOR flag so it doesn't make sense to have it >> enabled by default when KVM is enabled. >> >> The rationale here is similar to the cases where it makes sense to have >> a feature enabled by default on all CPU models when on KVM mode (e.g. >> x2apic). In this case we are having a feature disabled by default for >> the same reasons. >> >> In this case we don't need machine-type compat code because it is >> currently impossible to run a KVM VM with the MONITOR flag set. >> >> Signed-off-by: Eduardo Habkost <ehabk...@redhat.com> > > Why relying on the kernel filtering is not sufficient ?
Because that would break "-cpu ...,enforce". In fact many old models are currently broken because they were never tested with "-cpu ...,enforce". For example: $ qemu-system-x86_64 -cpu core2duo,enforce --enable-kvm warning: host doesn't support requested feature: CPUID.01H:EDX.ds [bit 21] warning: host doesn't support requested feature: CPUID.01H:EDX.acpi [bit 22] warning: host doesn't support requested feature: CPUID.01H:EDX.ht [bit 28] warning: host doesn't support requested feature: CPUID.01H:EDX.tm [bit 29] warning: host doesn't support requested feature: CPUID.01H:EDX.pbe [bit 31] warning: host doesn't support requested feature: CPUID.01H:ECX.dtes64 [bit 2] warning: host doesn't support requested feature: CPUID.01H:ECX.monitor [bit 3] warning: host doesn't support requested feature: CPUID.01H:ECX.ds_cpl [bit 4] warning: host doesn't support requested feature: CPUID.01H:ECX.vmx [bit 5] warning: host doesn't support requested feature: CPUID.01H:ECX.est [bit 7] warning: host doesn't support requested feature: CPUID.01H:ECX.tm2 [bit 8] warning: host doesn't support requested feature: CPUID.01H:ECX.xtpr [bit 14] warning: host doesn't support requested feature: CPUID.01H:ECX.pdcm [bit 15] qemu-system-x86_64: Host's CPU doesn't support requested features Paolo
