x86: 0.947
architecture: 0.814
kernel: 0.798
device: 0.789
graphic: 0.772
vnc: 0.706
semantic: 0.601
ppc: 0.591
user-level: 0.478
hypervisor: 0.413
network: 0.400
performance: 0.364
socket: 0.356
files: 0.347
PID: 0.344
debug: 0.332
register: 0.321
i386: 0.307
permissions: 0.247
arm: 0.236
mistranslation: 0.227
peripherals: 0.223
VMM: 0.211
TCG: 0.206
boot: 0.201
virtual: 0.178
risc-v: 0.101
assembly: 0.094
KVM: 0.061
--------------------
x86: 0.993
hypervisor: 0.943
kernel: 0.760
debug: 0.756
virtual: 0.703
TCG: 0.051
files: 0.044
register: 0.032
PID: 0.023
socket: 0.019
KVM: 0.019
device: 0.017
performance: 0.013
VMM: 0.008
network: 0.006
architecture: 0.006
assembly: 0.005
user-level: 0.005
semantic: 0.004
i386: 0.003
boot: 0.003
ppc: 0.002
risc-v: 0.002
peripherals: 0.002
permissions: 0.001
graphic: 0.001
vnc: 0.001
mistranslation: 0.000
arm: 0.000

hvf: RDTSCP capability not passed to guests
Description of problem:

Steps to reproduce:
1. Run:
wget https://dl-cdn.alpinelinux.org/alpine/v3.15/releases/x86/alpine-standard-3.15.4-x86.iso
./qemu-system-x86_64 -cpu host,+rdtscp -machine q35,accel=hvf -m 512 -cdrom ./alpine-standard-3.15.4-x86.iso

2. login as "root"
3. type

cat /etc/cpuinfo | grep rdtscp

Expected result: cpu flag lines including rdtscp
Actual result: empty, with:

warning: host doesn't support requested feature: CPUID.80000001H:EDX.rdtscp [bit 27]
Additional information:
This patch apparently resolves the issue according to my tests:

https://lore.kernel.org/qemu-devel/20211101054836.21471-1-dirty@apple.com/