Changes since v4: - Temporary drop 'hv-evmcs' from the 'hv-default' set as handling it properly requires custom options parsers (we need to e.g distinguish between 'hv-default,-vmx' and 'hv-default,hv-evmcs,-vmx') but custom parsers are called evil. I'm not giving up on the idea, I just want to get things moving here. I'll be sending patches to add 'hv-evmcs' back separately. - Patch to support 'hv-passthrough,hv-feature=off' is also dropped for now, we'll get back to it later (with either custom option parsers or 'scratch CPUs' depending on 'hv-evmcs' discussion outcome). - Null-terminate hv-vendor string in 'hv-passthrough' mode (bug in PATCH1).
Original description: Upper layer tools like libvirt want to figure out which Hyper-V features are supported by the underlying stack (QEMU/KVM) but currently they are unable to do so. We have a nice 'hv_passthrough' CPU flag supported by QEMU but it has no effect on e.g. QMP's query-cpu-model-expansion type=full model={"name":"host","props":{"hv-passthrough":true}} command as we parse Hyper-V features after creating KVM vCPUs and not at feature expansion time. To support the use-case we first need to make KVM_GET_SUPPORTED_HV_CPUID ioctl a system-wide ioctl as the existing vCPU version can't be used that early. This is what KVM part does. With that done, we can make early Hyper-V feature expansion (this series). In addition, provide a simple 'hv-default' option which enables (and requires from KVM) all currently supported Hyper-V enlightenments except for 'hv-evmcs' (for now). Unlike 'hv-passthrough' mode, this is going to be migratable. Vitaly Kuznetsov (17): i386: keep hyperv_vendor string up-to-date i386: invert hyperv_spinlock_attempts setting logic with hv_passthrough i386: always fill Hyper-V CPUID feature leaves from X86CPU data i386: stop using env->features[] for filling Hyper-V CPUIDs i386: introduce hyperv_feature_supported() i386: introduce hv_cpuid_get_host() i386: drop FEAT_HYPERV feature leaves i386: introduce hv_cpuid_cache i386: split hyperv_handle_properties() into hyperv_expand_features()/hyperv_fill_cpuids() i386: move eVMCS enablement to hyperv_init_vcpu() i386: switch hyperv_expand_features() to using error_setg() i386: adjust the expected KVM_GET_SUPPORTED_HV_CPUID array size i386: prefer system KVM_GET_SUPPORTED_HV_CPUID ioctl over vCPU's one i386: use global kvm_state in hyperv_enabled() check i386: expand Hyper-V features during CPU feature expansion time i386: provide simple 'hv-default=on' option qtest/hyperv: Introduce a simple hyper-v test MAINTAINERS | 1 + docs/hyperv.txt | 18 +- target/i386/cpu.c | 163 +++++------- target/i386/cpu.h | 9 +- target/i386/kvm/kvm-stub.c | 5 + target/i386/kvm/kvm.c | 517 ++++++++++++++++++++----------------- target/i386/kvm/kvm_i386.h | 1 + tests/qtest/hyperv-test.c | 270 +++++++++++++++++++ tests/qtest/meson.build | 3 +- 9 files changed, 645 insertions(+), 342 deletions(-) create mode 100644 tests/qtest/hyperv-test.c -- 2.29.2