QEMU full virtualization – CPU emulations (enable/disable CPU flags/instruction sets) of QEMU 8.0

Yet another update to this QEMU series after the versions 2.0.0QEMU full virtualization – CPU emulations (enable/disable CPU flags/instruction sets) of QEMU 2.0.0 and version 6.2QEMU full virtualization – CPU emulations (enable/disable CPU flags/instruction sets) of QEMU 6.2.0

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The latest version of QEMU is 8.0.4 and it offers way more CPU flags and features! You can use QEMU with nearly native full virtualization. Here are some important tips for the guest CPU to consider when using QEMU directly (without any virtualization manager like virt-manager, libvirt and so on).

TIP 1) CPU emulation of x86

You can see what options are available for host emulation with:

root@srv ~ # qemu-system-x86_64 -cpu help
Available CPUs:
x86 486                   (alias configured by machine type)
x86 486-v1                
x86 Broadwell             (alias configured by machine type)
x86 Broadwell-IBRS        (alias of Broadwell-v3)
x86 Broadwell-noTSX       (alias of Broadwell-v2)
x86 Broadwell-noTSX-IBRS  (alias of Broadwell-v4)
x86 Broadwell-v1          Intel Core Processor (Broadwell)
x86 Broadwell-v2          Intel Core Processor (Broadwell, no TSX)
x86 Broadwell-v3          Intel Core Processor (Broadwell, IBRS)
x86 Broadwell-v4          Intel Core Processor (Broadwell, no TSX, IBRS)
x86 Cascadelake-Server    (alias configured by machine type)
x86 Cascadelake-Server-noTSX  (alias of Cascadelake-Server-v3)
x86 Cascadelake-Server-v1  Intel Xeon Processor (Cascadelake)
x86 Cascadelake-Server-v2  Intel Xeon Processor (Cascadelake) [ARCH_CAPABILITIES]
x86 Cascadelake-Server-v3  Intel Xeon Processor (Cascadelake) [ARCH_CAPABILITIES, no TSX]
x86 Cascadelake-Server-v4  Intel Xeon Processor (Cascadelake) [ARCH_CAPABILITIES, no TSX]
x86 Cascadelake-Server-v5  Intel Xeon Processor (Cascadelake) [ARCH_CAPABILITIES, EPT switching, XSAVES, no TSX]
x86 Conroe                (alias configured by machine type)
x86 Conroe-v1             Intel Celeron_4x0 (Conroe/Merom Class Core 2)
x86 Cooperlake            (alias configured by machine type)
x86 Cooperlake-v1         Intel Xeon Processor (Cooperlake)
x86 Cooperlake-v2         Intel Xeon Processor (Cooperlake) [XSAVES]
x86 Denverton             (alias configured by machine type)
x86 Denverton-v1          Intel Atom Processor (Denverton)
x86 Denverton-v2          Intel Atom Processor (Denverton) [no MPX, no MONITOR]
x86 Denverton-v3          Intel Atom Processor (Denverton) [XSAVES, no MPX, no MONITOR]
x86 Dhyana                (alias configured by machine type)
x86 Dhyana-v1             Hygon Dhyana Processor
x86 Dhyana-v2             Hygon Dhyana Processor [XSAVES]
x86 EPYC                  (alias configured by machine type)
x86 EPYC-IBPB             (alias of EPYC-v2)
x86 EPYC-Milan            (alias configured by machine type)
x86 EPYC-Milan-v1         AMD EPYC-Milan Processor
x86 EPYC-Rome             (alias configured by machine type)
x86 EPYC-Rome-v1          AMD EPYC-Rome Processor
x86 EPYC-Rome-v2          AMD EPYC-Rome Processor
x86 EPYC-v1               AMD EPYC Processor
x86 EPYC-v2               AMD EPYC Processor (with IBPB)
x86 EPYC-v3               AMD EPYC Processor
x86 Haswell               (alias configured by machine type)
x86 Haswell-IBRS          (alias of Haswell-v3)
x86 Haswell-noTSX         (alias of Haswell-v2)
x86 Haswell-noTSX-IBRS    (alias of Haswell-v4)
x86 Haswell-v1            Intel Core Processor (Haswell)
x86 Haswell-v2            Intel Core Processor (Haswell, no TSX)
x86 Haswell-v3            Intel Core Processor (Haswell, IBRS)
x86 Haswell-v4            Intel Core Processor (Haswell, no TSX, IBRS)
x86 Icelake-Server        (alias configured by machine type)
x86 Icelake-Server-noTSX  (alias of Icelake-Server-v2)
x86 Icelake-Server-v1     Intel Xeon Processor (Icelake)
x86 Icelake-Server-v2     Intel Xeon Processor (Icelake) [no TSX]
x86 Icelake-Server-v3     Intel Xeon Processor (Icelake)
x86 Icelake-Server-v4     Intel Xeon Processor (Icelake)
x86 Icelake-Server-v5     Intel Xeon Processor (Icelake) [XSAVES]
x86 Icelake-Server-v6     Intel Xeon Processor (Icelake) [5-level EPT]
x86 IvyBridge             (alias configured by machine type)
x86 IvyBridge-IBRS        (alias of IvyBridge-v2)
x86 IvyBridge-v1          Intel Xeon E3-12xx v2 (Ivy Bridge)
x86 IvyBridge-v2          Intel Xeon E3-12xx v2 (Ivy Bridge, IBRS)
x86 KnightsMill           (alias configured by machine type)
x86 KnightsMill-v1        Intel Xeon Phi Processor (Knights Mill)
x86 Nehalem               (alias configured by machine type)
x86 Nehalem-IBRS          (alias of Nehalem-v2)
x86 Nehalem-v1            Intel Core i7 9xx (Nehalem Class Core i7)
x86 Nehalem-v2            Intel Core i7 9xx (Nehalem Core i7, IBRS update)
x86 Opteron_G1            (alias configured by machine type)
x86 Opteron_G1-v1         AMD Opteron 240 (Gen 1 Class Opteron)
x86 Opteron_G2            (alias configured by machine type)
x86 Opteron_G2-v1         AMD Opteron 22xx (Gen 2 Class Opteron)
x86 Opteron_G3            (alias configured by machine type)
x86 Opteron_G3-v1         AMD Opteron 23xx (Gen 3 Class Opteron)
x86 Opteron_G4            (alias configured by machine type)
x86 Opteron_G4-v1         AMD Opteron 62xx class CPU
x86 Opteron_G5            (alias configured by machine type)
x86 Opteron_G5-v1         AMD Opteron 63xx class CPU
x86 Penryn                (alias configured by machine type)
x86 Penryn-v1             Intel Core 2 Duo P9xxx (Penryn Class Core 2)
x86 SandyBridge           (alias configured by machine type)
x86 SandyBridge-IBRS      (alias of SandyBridge-v2)
x86 SandyBridge-v1        Intel Xeon E312xx (Sandy Bridge)
x86 SandyBridge-v2        Intel Xeon E312xx (Sandy Bridge, IBRS update)
x86 SapphireRapids        (alias configured by machine type)
x86 SapphireRapids-v1     Intel Xeon Processor (SapphireRapids)
x86 Skylake-Client        (alias configured by machine type)
x86 Skylake-Client-IBRS   (alias of Skylake-Client-v2)
x86 Skylake-Client-noTSX-IBRS  (alias of Skylake-Client-v3)
x86 Skylake-Client-v1     Intel Core Processor (Skylake)
x86 Skylake-Client-v2     Intel Core Processor (Skylake, IBRS)
x86 Skylake-Client-v3     Intel Core Processor (Skylake, IBRS, no TSX)
x86 Skylake-Client-v4     Intel Core Processor (Skylake, IBRS, no TSX) [IBRS, XSAVES, no TSX]
x86 Skylake-Server        (alias configured by machine type)
x86 Skylake-Server-IBRS   (alias of Skylake-Server-v2)
x86 Skylake-Server-noTSX-IBRS  (alias of Skylake-Server-v3)
x86 Skylake-Server-v1     Intel Xeon Processor (Skylake)
x86 Skylake-Server-v2     Intel Xeon Processor (Skylake, IBRS)
x86 Skylake-Server-v3     Intel Xeon Processor (Skylake, IBRS, no TSX)
x86 Skylake-Server-v4     Intel Xeon Processor (Skylake, IBRS, no TSX)
x86 Skylake-Server-v5     Intel Xeon Processor (Skylake, IBRS, no TSX) [IBRS, XSAVES, EPT switching, no TSX]
x86 Snowridge             (alias configured by machine type)
x86 Snowridge-v1          Intel Atom Processor (SnowRidge)
x86 Snowridge-v2          Intel Atom Processor (Snowridge, no MPX)
x86 Snowridge-v3          Intel Atom Processor (Snowridge, no MPX) [XSAVES, no MPX]
x86 Snowridge-v4          Intel Atom Processor (Snowridge, no MPX) [no split lock detect, no core-capability]
x86 Westmere              (alias configured by machine type)
x86 Westmere-IBRS         (alias of Westmere-v2)
x86 Westmere-v1           Westmere E56xx/L56xx/X56xx (Nehalem-C)
x86 Westmere-v2           Westmere E56xx/L56xx/X56xx (IBRS update)
x86 athlon                (alias configured by machine type)
x86 athlon-v1             QEMU Virtual CPU version 2.5+
x86 core2duo              (alias configured by machine type)
x86 core2duo-v1           Intel(R) Core(TM)2 Duo CPU     T7700  @ 2.40GHz
x86 coreduo               (alias configured by machine type)
x86 coreduo-v1            Genuine Intel(R) CPU           T2600  @ 2.16GHz
x86 kvm32                 (alias configured by machine type)
x86 kvm32-v1              Common 32-bit KVM processor
x86 kvm64                 (alias configured by machine type)
x86 kvm64-v1              Common KVM processor
x86 n270                  (alias configured by machine type)
x86 n270-v1               Intel(R) Atom(TM) CPU N270   @ 1.60GHz
x86 pentium               (alias configured by machine type)
x86 pentium-v1            
x86 pentium2              (alias configured by machine type)
x86 pentium2-v1           
x86 pentium3              (alias configured by machine type)
x86 pentium3-v1           
x86 phenom                (alias configured by machine type)
x86 phenom-v1             AMD Phenom(tm) 9550 Quad-Core Processor
x86 qemu32                (alias configured by machine type)
x86 qemu32-v1             QEMU Virtual CPU version 2.5+
x86 qemu64                (alias configured by machine type)
x86 qemu64-v1             QEMU Virtual CPU version 2.5+
x86 base                  base CPU model type with no features enabled
x86 host                  processor with all supported host features 
x86 max                   Enables all features supported by the accelerator in the current host

Recognized CPUID flags:
  3dnow 3dnowext 3dnowprefetch abm ace2 ace2-en acpi adx aes amd-no-ssb
  amd-ssbd amd-stibp amx-bf16 amx-int8 amx-tile apic arat arch-capabilities
  arch-lbr avic avx avx-vnni avx2 avx512-4fmaps avx512-4vnniw avx512-bf16
  avx512-fp16 avx512-vp2intersect avx512-vpopcntdq avx512bitalg avx512bw
  avx512cd avx512dq avx512er avx512f avx512ifma avx512pf avx512vbmi
  avx512vbmi2 avx512vl avx512vnni bmi1 bmi2 bus-lock-detect cid cldemote
  clflush clflushopt clwb clzero cmov cmp-legacy core-capability cr8legacy
  cx16 cx8 dca de decodeassists ds ds-cpl dtes64 erms est extapic f16c
  flushbyasid fma fma4 fpu fsgsbase fsrc fsrm fsrs full-width-write fxsr
  fxsr-opt fzrm gfni hle ht hypervisor ia64 ibpb ibrs ibrs-all ibs intel-pt
  intel-pt-lip invpcid invtsc kvm-asyncpf kvm-asyncpf-int
  kvm-hint-dedicated kvm-mmu kvm-msi-ext-dest-id kvm-nopiodelay
  kvm-poll-control kvm-pv-eoi kvm-pv-ipi kvm-pv-sched-yield
  kvm-pv-tlb-flush kvm-pv-unhalt kvm-steal-time kvmclock kvmclock
  kvmclock-stable-bit la57 lahf-lm lbrv lm lwp mca mce md-clear mds-no
  misalignsse mmx mmxext monitor movbe movdir64b movdiri mpx msr mtrr
  nodeid-msr npt nrip-save nx osvw pae pat pause-filter pbe pcid pclmulqdq
  pcommit pdcm pdpe1gb perfctr-core perfctr-nb pfthreshold pge phe phe-en
  pks pku pmm pmm-en pn pni popcnt pschange-mc-no pse pse36 rdctl-no rdpid
  rdrand rdseed rdtscp rsba rtm sep serialize sgx sgx-aex-notify sgx-debug
  sgx-edeccssa sgx-exinfo sgx-kss sgx-mode64 sgx-provisionkey sgx-tokenkey
  sgx1 sgx2 sgxlc sha-ni skinit skip-l1dfl-vmentry smap smep smx spec-ctrl
  split-lock-detect ss ssb-no ssbd sse sse2 sse4.1 sse4.2 sse4a ssse3 stibp
  svm svm-lock svme-addr-chk syscall taa-no tbm tce tm tm2 topoext tsc
  tsc-adjust tsc-deadline tsc-scale tsx-ctrl tsx-ldtrk umip v-vmsave-vmload
  vaes vgif virt-ssbd vmcb-clean vme vmx vmx-activity-hlt
  vmx-activity-shutdown vmx-activity-wait-sipi vmx-apicv-register
  vmx-apicv-vid vmx-apicv-x2apic vmx-apicv-xapic vmx-cr3-load-noexit
  vmx-cr3-store-noexit vmx-cr8-load-exit vmx-cr8-store-exit vmx-desc-exit
  vmx-encls-exit vmx-entry-ia32e-mode vmx-entry-load-bndcfgs
  vmx-entry-load-efer vmx-entry-load-pat vmx-entry-load-perf-global-ctrl
  vmx-entry-load-pkrs vmx-entry-load-rtit-ctl vmx-entry-noload-debugctl
  vmx-ept vmx-ept-1gb vmx-ept-2mb vmx-ept-advanced-exitinfo
  vmx-ept-execonly vmx-eptad vmx-eptp-switching vmx-exit-ack-intr
  vmx-exit-clear-bndcfgs vmx-exit-clear-rtit-ctl vmx-exit-load-efer
  vmx-exit-load-pat vmx-exit-load-perf-global-ctrl vmx-exit-load-pkrs
  vmx-exit-nosave-debugctl vmx-exit-save-efer vmx-exit-save-pat
  vmx-exit-save-preemption-timer vmx-flexpriority vmx-hlt-exit vmx-ins-outs
  vmx-intr-exit vmx-invept vmx-invept-all-context vmx-invept-single-context
  vmx-invept-single-context vmx-invept-single-context-noglobals
  vmx-invlpg-exit vmx-invpcid-exit vmx-invvpid vmx-invvpid-all-context
  vmx-invvpid-single-addr vmx-io-bitmap vmx-io-exit vmx-monitor-exit
  vmx-movdr-exit vmx-msr-bitmap vmx-mtf vmx-mwait-exit vmx-nmi-exit
  vmx-page-walk-4 vmx-page-walk-5 vmx-pause-exit vmx-ple vmx-pml
  vmx-posted-intr vmx-preemption-timer vmx-rdpmc-exit vmx-rdrand-exit
  vmx-rdseed-exit vmx-rdtsc-exit vmx-rdtscp-exit vmx-secondary-ctls
  vmx-shadow-vmcs vmx-store-lma vmx-true-ctls vmx-tsc-offset
  vmx-tsc-scaling vmx-unrestricted-guest vmx-vintr-pending vmx-vmfunc
  vmx-vmwrite-vmexit-fields vmx-vnmi vmx-vnmi-pending vmx-vpid
  vmx-wbinvd-exit vmx-xsaves vmx-zero-len-inject vpclmulqdq waitpkg
  wbnoinvd wdt x2apic xcrypt xcrypt-en xfd xgetbv1 xop xsave xsavec
  xsaveerptr xsaveopt xsaves xstore xstore-en xtpr

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