Description of problem: Capability 'flushbyasid' is present in CPU flags on host, but it doesn't reflect in the guest using host-passthrough, even if specified manually. Version-Release number of selected component (if applicable): CentOS9 Stream [root@pollos log]# uname -a Linux pollos 5.14.0-316.el9.x86_64 #1 SMP PREEMPT_DYNAMIC Fri May 19 11:26:13 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux [root@pollos log]# libvirtd --version libvirtd (libvirt) 9.3.0 Steps to Reproduce: 1. Create a VM 2. Choose host-passthrough 3. Check on guest that the capability is missing Actual results: 2023-06-21T22:43:20.956233Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.956528Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.956824Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.957340Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.957650Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.957946Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.958489Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.958789Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.959115Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.959418Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.959952Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.960252Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] 2023-06-21T22:43:20.960548Z qemu-kvm: warning: host doesn't support requested feature: CPUID.8000000AH:EDX.flushbyasid [bit 6] Expected results: The VM starts and the flag is visible in guest VM. Additional info: [root@pollos log]# lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Address sizes: 43 bits physical, 48 bits virtual Byte Order: Little Endian CPU(s): 48 On-line CPU(s) list: 0-47 Vendor ID: AuthenticAMD BIOS Vendor ID: Advanced Micro Devices, Inc. Model name: AMD EPYC 7401P 24-Core Processor BIOS Model name: AMD EPYC 7401P 24-Core Processor CPU family: 23 Model: 1 Thread(s) per core: 2 Core(s) per socket: 24 Socket(s): 1 Stepping: 2 Frequency boost: enabled CPU max MHz: 2000.0000 CPU min MHz: 1200.0000 BogoMIPS: 3999.46 Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid amd_dcm aperfmperf rapl pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a m isalignsse 3dnowprefetch osvw skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb hw_pstate ssbd ibpb vmmcall fsgsbase bmi1 avx2 smep bmi2 rdseed adx smap clflus hopt sha_ni xsaveopt xsavec xgetbv1 xsaves clzero irperf xsaveerptr arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave _vmload vgif overflow_recov succor smca sme sev sev_es Virtualization features: Virtualization: AMD-V Caches (sum of all): L1d: 768 KiB (24 instances) L1i: 1.5 MiB (24 instances) L2: 12 MiB (24 instances) L3: 64 MiB (8 instances) NUMA: NUMA node(s): 4 NUMA node0 CPU(s): 0-5,24-29 NUMA node1 CPU(s): 6-11,30-35 NUMA node2 CPU(s): 12-17,36-41 NUMA node3 CPU(s): 18-23,42-47 Vulnerabilities: Itlb multihit: Not affected L1tf: Not affected Mds: Not affected Meltdown: Not affected Mmio stale data: Not affected Retbleed: Mitigation; untrained return thunk; SMT vulnerable Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization Spectre v2: Mitigation; Retpolines, IBPB conditional, STIBP disabled, RSB filling, PBRSB-eIBRS Not affected Srbds: Not affected Tsx async abort: Not affected =========================================== [root@pollos log]# virsh capabilities <capabilities> <host> <uuid>db938000-fd74-11e7-8000-e0d55e99ab5c</uuid> <cpu> <arch>x86_64</arch> <model>EPYC-IBPB</model> <vendor>AMD</vendor> <microcode version='134222444'/> <signature family='23' model='1' stepping='2'/> <counter name='tsc' frequency='2000003000' scaling='yes'/> <topology sockets='1' dies='1' cores='6' threads='2'/> <maxphysaddr mode='emulate' bits='43'/> <feature name='ht'/> <feature name='monitor'/> <feature name='osxsave'/> <feature name='xsaves'/> <feature name='cmp_legacy'/> <feature name='extapic'/> <feature name='skinit'/> <feature name='wdt'/> <feature name='tce'/> <feature name='topoext'/> <feature name='perfctr_core'/> <feature name='perfctr_nb'/> <feature name='invtsc'/> <feature name='clzero'/> <feature name='xsaveerptr'/> <feature name='npt'/> <feature name='lbrv'/> <feature name='svm-lock'/> <feature name='nrip-save'/> <feature name='tsc-scale'/> <feature name='vmcb-clean'/> <feature name='flushbyasid'/> <feature name='decodeassists'/> <feature name='pause-filter'/> <feature name='pfthreshold'/> <feature name='avic'/> <feature name='v-vmsave-vmload'/> <feature name='vgif'/> <pages unit='KiB' size='4'/> <pages unit='KiB' size='2048'/> <pages unit='KiB' size='1048576'/> </cpu> <power_management> <suspend_mem/> <suspend_disk/> <suspend_hybrid/> </power_management> <iommu support='no'/> <migration_features> <live/> <uri_transports> <uri_transport>tcp</uri_transport> <uri_transport>rdma</uri_transport> </uri_transports> </migration_features> <topology> <cells num='4'> <cell id='0'> <memory unit='KiB'>32321396</memory> <pages unit='KiB' size='4'>8080349</pages> <pages unit='KiB' size='2048'>0</pages> <pages unit='KiB' size='1048576'>0</pages> <distances> <sibling id='0' value='10'/> <sibling id='1' value='16'/> <sibling id='2' value='16'/> <sibling id='3' value='16'/> </distances> <cpus num='12'> <cpu id='0' socket_id='0' die_id='0' core_id='0' siblings='0,24'/> <cpu id='1' socket_id='0' die_id='0' core_id='1' siblings='1,25'/> <cpu id='2' socket_id='0' die_id='0' core_id='2' siblings='2,26'/> <cpu id='3' socket_id='0' die_id='0' core_id='4' siblings='3,27'/> <cpu id='4' socket_id='0' die_id='0' core_id='5' siblings='4,28'/> <cpu id='5' socket_id='0' die_id='0' core_id='6' siblings='5,29'/> <cpu id='24' socket_id='0' die_id='0' core_id='0' siblings='0,24'/> <cpu id='25' socket_id='0' die_id='0' core_id='1' siblings='1,25'/> <cpu id='26' socket_id='0' die_id='0' core_id='2' siblings='2,26'/> <cpu id='27' socket_id='0' die_id='0' core_id='4' siblings='3,27'/> <cpu id='28' socket_id='0' die_id='0' core_id='5' siblings='4,28'/> <cpu id='29' socket_id='0' die_id='0' core_id='6' siblings='5,29'/> </cpus> </cell> <cell id='1'> <memory unit='KiB'>33026508</memory> <pages unit='KiB' size='4'>8256627</pages> <pages unit='KiB' size='2048'>0</pages> <pages unit='KiB' size='1048576'>0</pages> <distances> <sibling id='0' value='16'/> <sibling id='1' value='10'/> <sibling id='2' value='16'/> <sibling id='3' value='16'/> </distances> <cpus num='12'> <cpu id='6' socket_id='0' die_id='1' core_id='8' siblings='6,30'/> <cpu id='7' socket_id='0' die_id='1' core_id='9' siblings='7,31'/> <cpu id='8' socket_id='0' die_id='1' core_id='10' siblings='8,32'/> <cpu id='9' socket_id='0' die_id='1' core_id='12' siblings='9,33'/> <cpu id='10' socket_id='0' die_id='1' core_id='13' siblings='10,34'/> <cpu id='11' socket_id='0' die_id='1' core_id='14' siblings='11,35'/> <cpu id='30' socket_id='0' die_id='1' core_id='8' siblings='6,30'/> <cpu id='31' socket_id='0' die_id='1' core_id='9' siblings='7,31'/> <cpu id='32' socket_id='0' die_id='1' core_id='10' siblings='8,32'/> <cpu id='33' socket_id='0' die_id='1' core_id='12' siblings='9,33'/> <cpu id='34' socket_id='0' die_id='1' core_id='13' siblings='10,34'/> <cpu id='35' socket_id='0' die_id='1' core_id='14' siblings='11,35'/> </cpus> </cell> <cell id='2'> <memory unit='KiB'>32986160</memory> <pages unit='KiB' size='4'>8246540</pages> <pages unit='KiB' size='2048'>0</pages> <pages unit='KiB' size='1048576'>0</pages> <distances> <sibling id='0' value='16'/> <sibling id='1' value='16'/> <sibling id='2' value='10'/> <sibling id='3' value='16'/> </distances> <cpus num='12'> <cpu id='12' socket_id='0' die_id='2' core_id='16' siblings='12,36'/> <cpu id='13' socket_id='0' die_id='2' core_id='17' siblings='13,37'/> <cpu id='14' socket_id='0' die_id='2' core_id='18' siblings='14,38'/> <cpu id='15' socket_id='0' die_id='2' core_id='20' siblings='15,39'/> <cpu id='16' socket_id='0' die_id='2' core_id='21' siblings='16,40'/> <cpu id='17' socket_id='0' die_id='2' core_id='22' siblings='17,41'/> <cpu id='36' socket_id='0' die_id='2' core_id='16' siblings='12,36'/> <cpu id='37' socket_id='0' die_id='2' core_id='17' siblings='13,37'/> <cpu id='38' socket_id='0' die_id='2' core_id='18' siblings='14,38'/> <cpu id='39' socket_id='0' die_id='2' core_id='20' siblings='15,39'/> <cpu id='40' socket_id='0' die_id='2' core_id='21' siblings='16,40'/> <cpu id='41' socket_id='0' die_id='2' core_id='22' siblings='17,41'/> </cpus> </cell> <cell id='3'> <memory unit='KiB'>33023604</memory> <pages unit='KiB' size='4'>8255901</pages> <pages unit='KiB' size='2048'>0</pages> <pages unit='KiB' size='1048576'>0</pages> <distances> <sibling id='0' value='16'/> <sibling id='1' value='16'/> <sibling id='2' value='16'/> <sibling id='3' value='10'/> </distances> <cpus num='12'> <cpu id='18' socket_id='0' die_id='3' core_id='24' siblings='18,42'/> <cpu id='19' socket_id='0' die_id='3' core_id='25' siblings='19,43'/> <cpu id='20' socket_id='0' die_id='3' core_id='26' siblings='20,44'/> <cpu id='21' socket_id='0' die_id='3' core_id='28' siblings='21,45'/> <cpu id='22' socket_id='0' die_id='3' core_id='29' siblings='22,46'/> <cpu id='23' socket_id='0' die_id='3' core_id='30' siblings='23,47'/> <cpu id='42' socket_id='0' die_id='3' core_id='24' siblings='18,42'/> <cpu id='43' socket_id='0' die_id='3' core_id='25' siblings='19,43'/> <cpu id='44' socket_id='0' die_id='3' core_id='26' siblings='20,44'/> <cpu id='45' socket_id='0' die_id='3' core_id='28' siblings='21,45'/> <cpu id='46' socket_id='0' die_id='3' core_id='29' siblings='22,46'/> <cpu id='47' socket_id='0' die_id='3' core_id='30' siblings='23,47'/> </cpus> </cell> </cells> </topology> <cache> <bank id='0' level='3' type='both' size='8' unit='MiB' cpus='0-2,24-26'/> <bank id='1' level='3' type='both' size='8' unit='MiB' cpus='3-5,27-29'/> <bank id='2' level='3' type='both' size='8' unit='MiB' cpus='6-8,30-32'/> <bank id='3' level='3' type='both' size='8' unit='MiB' cpus='9-11,33-35'/> <bank id='4' level='3' type='both' size='8' unit='MiB' cpus='12-14,36-38'/> <bank id='5' level='3' type='both' size='8' unit='MiB' cpus='15-17,39-41'/> <bank id='6' level='3' type='both' size='8' unit='MiB' cpus='18-20,42-44'/> <bank id='7' level='3' type='both' size='8' unit='MiB' cpus='21-23,45-47'/> </cache> <secmodel> <model>selinux</model> <doi>0</doi> <baselabel type='kvm'>system_u:system_r:svirt_t:s0</baselabel> <baselabel type='qemu'>system_u:system_r:svirt_tcg_t:s0</baselabel> </secmodel> <secmodel> <model>dac</model> <doi>0</doi> <baselabel type='kvm'>+107:+107</baselabel> <baselabel type='qemu'>+107:+107</baselabel> </secmodel> </host> <guest> <os_type>hvm</os_type> <arch name='i686'> <wordsize>32</wordsize> <emulator>/usr/libexec/qemu-kvm</emulator> <machine maxCpus='240' deprecated='yes'>pc-i440fx-rhel7.6.0</machine> <machine canonical='pc-i440fx-rhel7.6.0' maxCpus='240' deprecated='yes'>pc</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.6.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.5.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.3.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel7.6.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.4.0</machine> <machine maxCpus='710'>pc-q35-rhel9.2.0</machine> <machine canonical='pc-q35-rhel9.2.0' maxCpus='710'>q35</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.2.0</machine> <machine maxCpus='710'>pc-q35-rhel9.0.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.0.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.1.0</machine> <domain type='qemu'/> <domain type='kvm'/> </arch> <features> <pae/> <nonpae/> <acpi default='on' toggle='yes'/> <apic default='on' toggle='no'/> <cpuselection/> <deviceboot/> <disksnapshot default='on' toggle='no'/> </features> </guest> <guest> <os_type>hvm</os_type> <arch name='x86_64'> <wordsize>64</wordsize> <emulator>/usr/libexec/qemu-kvm</emulator> <machine maxCpus='240' deprecated='yes'>pc-i440fx-rhel7.6.0</machine> <machine canonical='pc-i440fx-rhel7.6.0' maxCpus='240' deprecated='yes'>pc</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.6.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.5.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.3.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel7.6.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.4.0</machine> <machine maxCpus='710'>pc-q35-rhel9.2.0</machine> <machine canonical='pc-q35-rhel9.2.0' maxCpus='710'>q35</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.2.0</machine> <machine maxCpus='710'>pc-q35-rhel9.0.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.0.0</machine> <machine maxCpus='710' deprecated='yes'>pc-q35-rhel8.1.0</machine> <domain type='qemu'/> <domain type='kvm'/> </arch> <features> <acpi default='on' toggle='yes'/> <apic default='on' toggle='no'/> <cpuselection/> <deviceboot/> <disksnapshot default='on' toggle='no'/> </features> </guest> </capabilities>
Do you get warnings if you start QEMU with '-cpu host,flushbyasid=on' ?
Yes, that was one of the first tries, unfortunately
I can reproduce this issue on RHEL9.3 host with '-cpu host,enforce'. Host: 5.14.0-332.el9.x86_64 qemu-kvm-8.0.0-6.el9.x86_64 Model name: AMD EPYC 7251 8-Core Processor Guest: 5.14.0-332.el9.x86_64 CPUID on host: # cpuid -r -1 | grep -i 8000000a 0x8000000a 0x00: eax=0x00000001 ebx=0x00008000 ecx=0x00000000 edx=0x0001bcff CPUID inside guest: # cpuid -r -1 | grep -i 8000000a 0x8000000a 0x00: eax=0x00000001 ebx=0x00000010 ecx=0x00000000 edx=0x1001943b
(In reply to Alessandro Rossi from comment #3) > Yes, that was one of the first tries, unfortunately then what's the output of query-cpu-model-expansion command for host cpumodel?
ps: " qemu-kvm: warning: host doesn't support requested feature: foo" typically means that KVM doesn't support passing the flag to guest. CCing Vitaly who might know a bit more about flushbyasid (according to git blame on KVM backports to RHEL)
Hi @Igor, That's the output, not sure if that's what you are looking for: [kubealex@pollos tests]$ sudo virsh qemu-monitor-command idm-lab query-cpu-model-expansion {"id":"libvirt-444","error":{"class":"GenericError","desc":"Parameter 'type' is missing"}} The point is that 'flushbyasid' is just one of the capabilities that are present on the host and not passed to the guest, but it is actually a blocker for nested virt with ESXi (among others)
(In reply to Igor Mammedov from comment #6) > ps: > " qemu-kvm: warning: host doesn't support requested feature: foo" > typically means that KVM doesn't support passing the flag to guest. > > CCing Vitaly who might know a bit more about flushbyasid > (according to git blame on KVM backports to RHEL) I don't think KVM supports nested FLUSHBYASID, see commit 174a921b6975ef959dd82ee9e8844067a62e3ec1 Author: Krish Sadhukhan <krish.sadhukhan> Date: Mon Sep 20 19:51:31 2021 -0400 nSVM: Check for reserved encodings of TLB_CONTROL in nested VMCB and so you won't see it in svm_set_cpu_caps(). Cc: Max who seems to know something: https://lore.kernel.org/kvm/357d135f9ed65f4e2970c82ae4e855547db70ad1.camel@redhat.com/ :-)
So it's not supported according to comment 9. What bothers me though is that libvirt reports it in domcaps for host CPU which might be ok if it's description of host CPU but not if it is applied to 'host' CPU model in the end. Alessandro, it's QMP command, example how to use it (or google for other examples): https://kashyapc.fedorapeople.org/virt/qemu/query-cpu-mode-expansion-QMP-output.txt PS: put there 'host' cpu model
Here you go Igor: [kubealex@pollos ~]$ sudo virsh qemu-monitor-command idm-lab --pretty '{"execute": "query-cpu-model-expansion", "arguments": {"model": {"name": "host"}, "type": "full"}}' { "return": { "model": { "name": "host", "props": { "vmx-entry-load-rtit-ctl": false, "phys-bits": 0, "core-id": -1, "svme-addr-chk": true, "xlevel": 2147483681, "cmov": true, "ia64": false, "hv-version-id-minor": 1, "ssb-no": false, "aes": true, "vmx-apicv-xapic": false, "kvm-pv-enforce-cpuid": false, "mmx": true, "arat": true, "rdpid": false, "vmx-page-walk-5": false, "vmx-page-walk-4": false, "vmx-desc-exit": false, "gfni": false, "ibrs-all": false, "pause-filter": true, "bus-lock-detect": false, "xsavec": true, "intel-pt": false, "vmx-tsc-scaling": false, "vmx-cr8-store-exit": false, "hv-xmm-input": false, "hv-frequencies": false, "tsc-frequency": 0, "vmx-rdseed-exit": false, "xd": true, "x-intel-pt-auto-level": false, "hv-vendor-id": "", "vmx-eptp-switching": false, "hv-syndbg": false, "kvm-asyncpf": true, "kvm_asyncpf": true, "perfctr-core": true, "perfctr_core": true, "mpx": false, "avx512cd": false, "pbe": false, "decodeassists": false, "vmx-exit-load-efer": false, "vmx-exit-clear-bndcfgs": false, "sse4.1": true, "sse4-1": true, "sse4_1": true, "family": 23, "legacy-cache": true, "intel-pt-lip": false, "vmx-vmwrite-vmexit-fields": false, "vmx-vnmi": false, "kvm-asyncpf-int": false, "vmx-true-ctls": false, "host-phys-bits-limit": 48, "vmx-ept-execonly": false, "vmx-exit-save-efer": false, "vmx-invept-all-context": false, "vmware-cpuid-freq": true, "wbnoinvd": false, "avx512f": false, "xcrypt": false, "hv-runtime": false, "hv-stimer-direct": false, "mce": true, "mca": true, "msr": true, "sgx": false, "thread-id": -1, "vmx-exit-load-pat": false, "vmx-intr-exit": false, "min-level": 13, "vmx-flexpriority": false, "xgetbv1": true, "cid": false, "hv-relaxed": false, "sgx-exinfo": false, "avx512-bf16": false, "avx512-fp16": false, "ds": false, "hv-crash": false, "fxsr": true, "vmx-cr8-load-exit": false, "hv-version-id-sbranch": 0, "hv-version-id-snumber": 0, "xsaveopt": true, "arch-lbr": false, "vmx-apicv-vid": false, "vmx-exit-save-pat": false, "tsx-ctrl": false, "xtpr": false, "vmx-ple": false, "hv-evmcs": false, "avx512-vpopcntdq": false, "hv-version-id-spack": 0, "phe": false, "avx512vl": false, "extapic": false, "vmx-vmfunc": false, "3dnowprefetch": true, "vmx-activity-shutdown": false, "sgx1": false, "sgx2": false, "avx512vbmi2": false, "cr8legacy": true, "vmx-encls-exit": false, "stibp": false, "vmx-msr-bitmap": false, "cpuid-0xb": true, "xcrypt-en": false, "vmx-mwait-exit": false, "kvm_pv_eoi": true, "vmx-pml": false, "apic-id": 4294967295, "vmx-nmi-exit": false, "vmx-invept-single-context-noglobals": false, "amx-tile": false, "pn": false, "rsba": false, "dca": false, "vmx-unrestricted-guest": false, "vendor": "AuthenticAMD", "hv-ipi": false, "vmx-cr3-store-noexit": false, "pku": false, "pks": false, "smx": false, "cmp-legacy": true, "cmp_legacy": true, "node-id": -1, "avx512-4fmaps": false, "vmcb-clean": true, "vmcb_clean": true, "hle": false, "amd-no-ssb": false, "3dnowext": false, "avx-vnni": false, "npt": true, "sgxlc": false, "rdctl-no": true, "vmx-invvpid": false, "memory": "/machine/unattached/system[0]", "clwb": false, "lbrv": true, "adx": true, "ss": false, "pni": true, "tsx-ldtrk": false, "host-cache-info": false, "svm-lock": false, "svm_lock": false, "pfthreshold": true, "smap": true, "smep": true, "vmx-invpcid-exit": false, "amx-int8": false, "x2apic": true, "sgx-edeccssa": false, "avx512vnni": false, "avx512vbmi": false, "vmx-apicv-x2apic": false, "hv-stimer": false, "kvm-pv-sched-yield": true, "vmx-invlpg-exit": false, "x-hv-synic-kvm-only": true, "vmx-invvpid-all-context": false, "i64": true, "vmx-activity-hlt": false, "flushbyasid": false, "f16c": true, "vmx-exit-ack-intr": false, "ace2-en": false, "pae": true, "pat": true, "sse": true, "die-id": -1, "vmx-tsc-offset": false, "phe-en": false, "kvm-nopiodelay": true, "kvm_nopiodelay": true, "tm": false, "hv-enforce-cpuid": false, "kvmclock-stable-bit": true, "vmx-rdtsc-exit": false, "hypervisor": true, "vmx-rdtscp-exit": false, "socket-id": -1, "mds-no": true, "pcommit": false, "vmx-vpid": false, "syscall": true, "level": 13, "avx512dq": false, "x-migrate-smi-count": false, "svm": true, "full-cpuid-auto-level": true, "hv-avic": false, "hv-reset": false, "invtsc": false, "vmx-monitor-exit": false, "sse2": true, "vmx-wbinvd-exit": false, "ssbd": false, "sse3": true, "est": false, "kvm-poll-control": true, "kvm_poll_control": true, "avx512ifma": false, "tm2": false, "start-powered-off": false, "kvm-pv-eoi": true, "kvm-pv-ipi": true, "hv-emsr-bitmap": false, "cx8": true, "vmx-invvpid-single-addr": false, "waitpkg": false, "sgx-tokenkey": false, "cldemote": false, "vmx-ept": false, "hv-tlbflush-direct": false, "xfd": false, "hv-reenlightenment": false, "kvm-mmu": false, "kvm_mmu": false, "sse4.2": true, "sse4-2": true, "sse4_2": true, "pge": true, "fill-mtrr-mask": true, "avx512bitalg": false, "vmx-entry-load-bndcfgs": false, "pdcm": false, "nodeid_msr": false, "vmx-exit-clear-rtit-ctl": false, "hv-apicv": false, "model": 1, "movbe": true, "nrip-save": true, "nrip_save": true, "vmx-pause-exit": false, "ssse3": true, "sse4a": true, "kvm-msi-ext-dest-id": false, "kvm_pv_unhalt": true, "sgx-debug": false, "invpcid": false, "pdpe1gb": true, "sgx-mode64": false, "tsc-deadline": true, "skip-l1dfl-vmentry": true, "vmx-exit-load-perf-global-ctrl": false, "fma": true, "cx16": true, "fzrm": false, "de": true, "hv-version-id-build": 7100, "enforce": false, "stepping": 2, "xsave": true, "lbr-fmt": 18446744073709551552, "lbr_fmt": 18446744073709551552, "clflush": true, "skinit": false, "tsc": true, "tce": false, "kvm_asyncpf_int": false, "fpu": true, "ds-cpl": false, "ibs": false, "ds_cpl": false, "fma4": false, "host-phys-bits": true, "sgx-kss": false, "vmx-exit-nosave-debugctl": false, "hv-version-id-major": 6, "vmx-invept": false, "la57": false, "osvw": true, "migratable": true, "check": true, "hv-spinlocks": 4294967295, "vmx-eptad": false, "vmx-entry-noload-debugctl": false, "pmu": true, "pmm": false, "apic": true, "spec-ctrl": false, "vmx-posted-intr": false, "vmx-apicv-register": false, "min-xlevel2": 0, "tsc-adjust": true, "tsc_adjust": true, "kvm-steal-time": true, "kvm_steal_time": true, "avx512-vp2intersect": false, "kvmclock": true, "vmx-zero-len-inject": false, "l3-cache": true, "pschange-mc-no": true, "v-vmsave-vmload": true, "sgx-provisionkey": false, "vmx-rdrand-exit": false, "lwp": false, "hv-passthrough": false, "amd-ssbd": false, "ibpb": true, "ibrs": false, "xop": false, "core-capability": false, "avx": true, "vmx-invept-single-context": false, "movdiri": false, "avx512bw": false, "acpi": false, "ace2": false, "fsgsbase": true, "hv-vapic": false, "vmx-ept-2mb": false, "vmx-ept-1gb": false, "ht": false, "vmx-io-exit": false, "nx": true, "pclmulqdq": true, "mmxext": true, "popcnt": true, "vaes": false, "serialize": false, "xsaves": true, "movdir64b": false, "vmx-shadow-vmcs": false, "tcg-cpuid": true, "lm": true, "vmx-exit-save-preemption-timer": false, "vmx-entry-load-pat": false, "fsrs": false, "fsrm": false, "fsrc": false, "vmx-entry-load-perf-global-ctrl": false, "vmx-io-bitmap": false, "vmx-store-lma": false, "umip": false, "vmx-movdr-exit": false, "avx2": true, "pse": true, "avic": false, "sep": true, "pclmuldq": true, "vmx-cr3-load-noexit": false, "virt-ssbd": true, "x-hv-max-vps": -1, "nodeid-msr": false, "md-clear": false, "split-lock-detect": false, "kvm": true, "misalignsse": true, "min-xlevel": 2147483681, "realized": false, "kvm-pv-unhalt": true, "bmi2": true, "bmi1": true, "xen-vapic": false, "tsc-scale": true, "tsc_scale": true, "topoext": false, "amd-stibp": false, "hv-vpindex": false, "hv-no-nonarch-coresharing": "off", "ucode-rev": 0, "vmx-preemption-timer": false, "xlevel2": 0, "vmx-entry-load-pkrs": false, "clflushopt": true, "vmx-vnmi-pending": false, "kvm-no-smi-migration": false, "monitor": false, "vmx-vintr-pending": false, "avx512er": false, "full-width-write": false, "pmm-en": false, "taa-no": false, "pcid": false, "vgif": true, "vmx-secondary-ctls": false, "vmx-xsaves": false, "arch-capabilities": true, "x-vendor-cpuid-only": false, "clzero": true, "3dnow": false, "erms": false, "x-force-features": false, "vmx-entry-ia32e-mode": false, "lahf-lm": true, "lahf_lm": true, "vmx-ins-outs": false, "vpclmulqdq": false, "xstore": false, "fxsr-opt": true, "hv-synic": false, "fxsr_opt": true, "sgx-aex-notify": false, "rtm": false, "kvm-hint-dedicated": false, "amx-bf16": false, "lmce": false, "hv-time": false, "perfctr-nb": false, "perfctr_nb": false, "hv-tlbflush": false, "ffxsr": true, "rdrand": true, "rdseed": true, "avx512-4vnniw": false, "vme": true, "vmx": false, "dtes64": false, "mtrr": true, "rdtscp": true, "xsaveerptr": true, "pse36": true, "kvm-pv-tlb-flush": true, "vmx-activity-wait-sipi": false, "tbm": false, "vmx-rdpmc-exit": false, "wdt": false, "vmx-entry-load-efer": false, "level-func7": 0, "vmx-mtf": false, "hv-tlbflush-ext": false, "pause_filter": true, "model-id": "AMD EPYC 7401P 24-Core Processor ", "sha-ni": true, "vmx-exit-load-pkrs": false, "abm": true, "vmx-ept-advanced-exitinfo": false, "avx512pf": false, "vmx-hlt-exit": false, "xstore-en": false } } }, "id": "libvirt-15242" }
'host' cpu model has flushbyasid=false which is correct considering it's not supported on kvm side. As for 'virsh capabilities' showing flushbyasid, according to docs it is not a description of cpu model in QEMU sense but rather a description of host's physical CPU. I'm closing BZ for now. If there is a usecase that requires flushbyasid support within guest, please reopen BZ and provide a justification why it's needed.