On 03/11/2015 20:58, Eduardo Habkost wrote: > The x86 change to make "check" mode be enabled by default made QEMU print > warnings in the default case if running in an Intel host: > > $ qemu-system-x86_64 -machine pc,accel=kvm > warning: host doesn't support requested feature: CPUID.80000001H:ECX.sse4a > [bit 6] > > There's also a warning when about missing the ABM feature if running on a > Sandy > Bridge or older host. > > ABM is not available on Sandy Bridge and older, SSE4a is not available in any > Intel host. We want to make the default CPU runnable in most hosts, so those > features won't be enabled by default in KVM mode. > > We should eventually have all features supported by TCG enabled by default in > TCG mode, but as we don't have a good mechanism today to ensure we have > different defaults in KVM and TCG mode, disable ABM and SSE4a in the qemu64 > CPU > model entirely. > > Also, as we can't change the guest ABI in pc-*-2.4, disable "check" mode by > default in pc-*-2.4 and older so we don't print spurious warnings. > > Note that with this change, the qemu64 CPU model still requires a host > supporting POPCNT (Nehalem or newer, and Opteron_G3 or newer).
Do we want to remove that one as well? > Eduardo Habkost (3): > target-i386: Set "check=off" by default on pc-*-2.4 and older > target-i386: Remove SSE4a from qemu64 CPU model > target-i386: Remove ABM from qemu64 CPU model > > include/hw/i386/pc.h | 15 +++++++++++++++ > target-i386/cpu.c | 3 +-- > 2 files changed, 16 insertions(+), 2 deletions(-) > In any case, Reviewed-by: Paolo Bonzini <pbonz...@redhat.com> Paolo
