Re: [RFC PATCH 1/3] kvm: x86: Rename KVM_DEBUGREG_RELOAD to KVM_DEBUGREG_NEED_RELOAD

[Nadav Amit]

> On Apr 25, 2020, at 1:07 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> 
> On 16/04/20 12:15, Xiaoyao Li wrote:
>> To make it more clear that the flag means DRn (except DR7) need to be
>> reloaded before vm entry.
>> 
>> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> 
> I wonder if KVM_DEBUGREG_RELOAD is needed at all.  It should be easy to
> write selftests for it, using the testcase in commit message
> 172b2386ed16 and the information in commit ae561edeb421.

I must be missing something, since I did not follow this thread and other
KVM changes very closely.

Yet, for the record, I added KVM_DEBUGREG_RELOAD due to real experienced
issues that I had while running Intelâs fuzzing tests on KVM: IIRC, the DRs
were not reloaded after an INIT event that clears them.

Personally, I would prefer that a test for that, if added, would be added
to KVM-unit-tests, based on Liranâs INIT test. This would allow to confirm
bare-metal behaves as the VM.