Messages in this thread | | | Subject | Re: [PATCH] KVM: X86: Also reload the debug registers before kvm_x86->run() when the host is using them | From | Paolo Bonzini <> | Date | Fri, 9 Jul 2021 17:52:09 +0200 |
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On 09/07/21 12:05, Lai Jiangshan wrote: > > > On 2021/7/9 17:49, Paolo Bonzini wrote: >> On 09/07/21 05:09, Lai Jiangshan wrote: >>> I just noticed that emulation.c fails to emulate with DBn. >>> Is there any problem around it? >> >> Just what you said, it's not easy and the needs are limited. I >> implemented kvm_vcpu_check_breakpoint because I was interested in >> using hardware breakpoints from gdb, even with unrestricted_guest=0 >> and invalid guest state, but that's it. > > It seems kvm_vcpu_check_breakpoint() handles only for code breakpoint > and doesn't handle for data breakpoints.
Correct, there's a comment above the call. But data breakpoint are much harder and relatively less useful.
> And no code handles DR7_GD bit when the emulation is not resulted from > vm-exit. (for example, the non-first instruction when kvm emulates > instructions back to back and the instruction accesses to DBn).
Good point, that should be fixed too.
Paolo
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