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boot: 0.784
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risc-v: 0.596
debug: 0.586
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hypervisor: 0.477
PID: 0.465
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arm: 0.421
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architecture: 0.378
ppc: 0.371
kernel: 0.370
VMM: 0.350
KVM: 0.291
peripherals: 0.288
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i386: 0.224
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RTC time could run slow 3s than host time when clock=vm & base=UTC
Description of problem:
When start qemu with `-rtc base=utc,clock=vm`, sometime guest time can slower 3s than host. There's no problem (also didn't be noticed) as we often start ntp service, who will adjust our system time. But let's talk about if we havn't enable NTP service(for example system just booted)

After inspect into the code, i found that there are two problem we should think about:
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Steps to reproduce:
1. start vm with `-rtc base=utc,clock=vm`
2. disable NTP (OS specific)`systemctl disable --now ntpd;systemctl disable --now ntpdate`
3. reboot in the guest
4. after guest started, compare guest time with host time(at the same time) `date +'%F %T.%3N'`
Additional information: