This v2 series is follow up work of [1],[2]. The initial purpose is to track CPUID_HT in env->features[] for x86. It's supposed to be implemented in x86_cpu_realizefn() and before qemu_init_vcpu(). However, CPUID_HT bit needs to be evaluated based on topology information, either 1) nr_cores and nr_threads of CPUState or 2) MachineState::smp.
1) are initialized in qemu_init_vcpu() which is too late. So [1] was sent to initialize nr_threads and nr_cores of CPUState earlier. It touches all the ARCHes and people disliked it. Followup attempt to initialize them in cpu_common_initfn() was also rejected. [3] 2) needs to grab MachineState in cpu context and was disagreed[3] As suggested by Igor[3], aduit nr_threads and nr_cores and initialize them in pre_plug() callback for the ARCHes where they are actually needed. I found nr_cores is only used by x86 and nr_threads is used by X86/MIPS/PPC[4]. I didn't play with MIPS and PPC before and I'm incapable to write patch for them. So I send an RFC work [2], which drops nr_cores from CPUState and it instead maintains a substitute for x86 only. The RFC work left how to handle nr_threads as open however I didn't get any feedback yet. Eventually, I decided to fix x86 only. The sulution is to maintain a X86CPUTopoInfo in CPUX86State, so that x86 doesn't need to use nr_threads and nr_cores anymore and the dependency on qemu_init_vcpu() goes away. x86 is the only user of CPUState::nr_core currently. When it switches to use CPUX86state::X86CPUTopoInfo, CPUState::nr_core loses its only user and can be dropped in patch 8. In the future, if MIPS and PPC starts to maintain nr_threads in its own CPU state, common CPUState::nr_threads can be dropped as well. Besides the patches to fulfill the main goal to track CPUID_HT in env->features[] for x86. This series also contains the cleanup patches during the work. [1] https://lore.kernel.org/qemu-devel/20241108070609.3653085-1-xiaoyao...@intel.com/ [2] https://lore.kernel.org/qemu-devel/20241205145716.472456-1-xiaoyao...@intel.com/ [3] https://lore.kernel.org/qemu-devel/20241125103857.78a23...@imammedo.users.ipa.redhat.com/ [4] https://lore.kernel.org/qemu-devel/045f9cb1-2b17-4b2c-985f-3c34e3626...@intel.com/ Xiaoyao Li (10): i386/cpu: Extract a common fucntion to setup value of MSR_CORE_THREAD_COUNT i386/cpu: Drop the variable smp_cores and smp_threads in x86_cpu_pre_plug() i386/cpu: Drop cores_per_pkg in cpu_x86_cpuid() i386/topology: Update the comment of x86_apicid_from_topo_ids() i386/topology: Introduce helpers for various topology info of different level i386/cpu: Track a X86CPUTopoInfo directly in CPUX86State i386/cpu: Hoist check of CPUID_EXT3_TOPOEXT against threads_per_core cpu: Remove nr_cores from struct CPUState i386/cpu: Set up CPUID_HT in x86_cpu_expand_features() instead of cpu_x86_cpuid() i386/cpu: Set and track CPUID_EXT3_CMP_LEG in env->features[FEAT_8000_0001_ECX] hw/core/cpu-common.c | 1 - hw/i386/x86-common.c | 22 +++--- include/hw/core/cpu.h | 2 - include/hw/i386/topology.h | 30 ++++++- system/cpus.c | 1 - target/i386/cpu-sysemu.c | 11 +++ target/i386/cpu.c | 113 ++++++++++++--------------- target/i386/cpu.h | 8 +- target/i386/hvf/x86_emu.c | 3 +- target/i386/kvm/kvm.c | 5 +- target/i386/tcg/sysemu/misc_helper.c | 3 +- 11 files changed, 103 insertions(+), 96 deletions(-) -- 2.34.1
