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From: Paolo Bonzini <pbonzini@redhat.com>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Xiaoyao Li <xiaoyao.li@intel.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	kvm <kvm@vger.kernel.org>, Nadav Amit <namit@cs.technion.ac.il>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 1/3] kvm: x86: Rename KVM_DEBUGREG_RELOAD to KVM_DEBUGREG_NEED_RELOAD
Date: Sat, 25 Apr 2020 21:16:14 +0200	[thread overview]
Message-ID: <8223a7e2-5d4a-b427-c44f-d76450f16748@redhat.com> (raw)
In-Reply-To: <08C6D1FB-A4F7-49FA-AC46-5323C104840A@gmail.com>

On 25/04/20 18:54, Nadav Amit wrote:
>> 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 Intel’s fuzzing tests on KVM: IIRC, the DRs
> were not reloaded after an INIT event that clears them.

Indeed, but the code has changed since then and I'm not sure it is still
needed.

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

Yes, that would be good as well of course.

Paolo


  reply	other threads:[~2020-04-25 19:16 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-16 10:15 [RFC PATCH 0/3] kvm: x86: Cleanup and optimazation of switch_db_regs Xiaoyao Li
2020-04-16 10:15 ` [RFC PATCH 1/3] kvm: x86: Rename KVM_DEBUGREG_RELOAD to KVM_DEBUGREG_NEED_RELOAD Xiaoyao Li
2020-04-23 19:09   ` Sean Christopherson
2020-04-24 13:28     ` Xiaoyao Li
2020-04-24 20:21     ` Peter Xu
2020-04-24 20:29       ` Sean Christopherson
2020-04-24 20:59         ` Peter Xu
2020-04-25  7:48       ` Paolo Bonzini
2020-04-27 14:37         ` Peter Xu
2020-04-27 16:06           ` Xiaoyao Li
2020-04-25  8:07   ` Paolo Bonzini
2020-04-25 16:54     ` Nadav Amit
2020-04-25 19:16       ` Paolo Bonzini [this message]
2020-04-16 10:15 ` [RFC PATCH 2/3] kvm: x86: Use KVM_DEBUGREG_NEED_RELOAD instead of KVM_DEBUGREG_BP_ENABLED Xiaoyao Li
2020-04-23 19:29   ` Sean Christopherson
2020-04-24 13:21     ` Xiaoyao Li
2020-04-16 10:15 ` [RFC PATCH 3/3] kvm: x86: skip DRn reload if previous VM exit is DR access VM exit Xiaoyao Li
2020-04-23 19:31   ` Sean Christopherson

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