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+virtual: 0.957
+graphic: 0.953
+permissions: 0.953
+semantic: 0.953
+debug: 0.951
+user-level: 0.950
+KVM: 0.943
+assembly: 0.942
+TCG: 0.940
+performance: 0.938
+PID: 0.937
+arm: 0.935
+mistranslation: 0.933
+architecture: 0.933
+device: 0.932
+kernel: 0.929
+peripherals: 0.928
+x86: 0.928
+network: 0.926
+risc-v: 0.924
+files: 0.923
+vnc: 0.921
+hypervisor: 0.916
+socket: 0.915
+register: 0.915
+boot: 0.913
+VMM: 0.897
+ppc: 0.876
+i386: 0.834
+
+Close gap for x86_64-v3 ABI in TCG - CPU support for fma, f16c, avx, avx2 features required
+Description of problem:
+There are 3 additional ABIs defined by a collaboration of vendors for the `x86_64` architecture, over the original baseline:
+
+* https://gitlab.com/x86-psABIs/x86-64-ABI/-/blob/master/x86-64-ABI/low-level-sys-info.tex
+
+This is no problem for KVM assuming suitable host hardware, but TCG is currently unable to support more than the original baseline and the `x86_64-v2` step.  
+
+For `x86_64-v3` there are some gaps in its emulation coverage. This can be seen by taking `Nehalem` which is a good fit for `x86_64-v2`, and requesting the extra v3 features:
+
+```
+$ qemu-system-x86_64 -accel tcg -cpu Nehalem,+avx,+avx2,+bmi1,+bmi2,+f16c,+fma,+abm,+movbe
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.fma [bit 12]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.avx [bit 28]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.f16c [bit 29]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.07H:EBX.avx2 [bit 5]
+```
+
+IOW, the strict bare minimum TCG needs in order to satisfy `x86_64-v3` is  `fma`, `f16c`, `avx` and `avx2` support
+
+If we want to fully support a named CPU model satisfying v3, then `Haswell` is the closest and that has a few additional gaps
+
+```
+$ qemu-system-x86_64 -accel tcg -cpu Haswell-noTSX
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.fma [bit 12]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.pcid [bit 17]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.x2apic [bit 21]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.tsc-deadline [bit 24]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.avx [bit 28]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.f16c [bit 29]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.07H:EBX.avx2 [bit 5]
+qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.07H:EBX.invpcid [bit 10]
+
+```
+
+Those additional gaps wouldn't impact ability to execute binaries build for the `x86_64-v3` ABI though, so not as important.
+
+The reason `x86_64-v3` compatibility in TCG matters is because sooner or later some Linux OS are going to set this as the baseline for their compiler toolchain.  There is a proposal to set this in `Fedora ELN`, which is what feeds in to a possible future `RHEL-10`.
+
+I imagine adding these extra features would be non-negligible work in TCG / take some time to complete.
+
+Thus I file this bug for the purpose of suggesting these 4 specific missing features be considered a priority to address, compared to other missing CPU features in TCG that might be considered more of a 'nice to have'.
+
+eg looking further the `x86_64-v4` baseline brings in a requirement for `avx512f`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512vl` which TCG also lacks, but I don't think they really need to be considered important at this point in time.