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From: Maxim Levitsky <mlevitsk@redhat.com>
To: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH v2 02/11] KVM: SVM: Don't BUG if userspace injects a soft interrupt with GIF=0
Date: Thu, 28 Apr 2022 17:34:44 +0300	[thread overview]
Message-ID: <b8a02f2eab780262c172cd4bbffd801ca8a37e98.camel@redhat.com> (raw)
In-Reply-To: <4baa5071-3fb6-64f3-bcd7-2ffc1181d811@maciej.szmigiero.name>

On Thu, 2022-04-28 at 15:27 +0200, Maciej S. Szmigiero wrote:
> On 28.04.2022 09:35, Maxim Levitsky wrote:
> > On Sat, 2022-04-23 at 02:14 +0000, Sean Christopherson wrote:
> > > From: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
> > > 
> > > Don't BUG/WARN on interrupt injection due to GIF being cleared if the
> > > injected event is a soft interrupt, which are not actually IRQs and thus
> > 
> > Are any injected events subject to GIF set? I think that EVENTINJ just injects
> > unconditionaly whatever hypervisor puts in it.
> 
> That's right, EVENTINJ will pretty much always inject, even when the CPU
> is in a 'wrong' state (like for example, injecting a hardware interrupt
> or a NMI with GIF masked).
> 
> But KVM as a L0 is not supposed to inject a hardware interrupt into guest
> with GIF unset since the guest is obviously not expecting it then.
> Hence this WARN_ON().

If you mean L0->L1 injection, that sure, but if L1 injects interrupt to L2,
then it should always be allowed to do so.


I am not sure that I am right here, just noticed something odd. I'll take
a better look at this next week.


Best regards,
	Maxim levitsky

> 
> > Best regards,
> > 	Maxim Levitsky
> 
> Thanks,
> Maciej
> 



  reply	other threads:[~2022-04-28 14:34 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-23  2:14 [PATCH v2 00/11] KVM: SVM: Fix soft int/ex re-injection Sean Christopherson
2022-04-23  2:14 ` [PATCH v2 01/11] KVM: nSVM: Sync next_rip field from vmcb12 to vmcb02 Sean Christopherson
2022-04-28  9:33   ` Maxim Levitsky
2022-04-23  2:14 ` [PATCH v2 02/11] KVM: SVM: Don't BUG if userspace injects a soft interrupt with GIF=0 Sean Christopherson
2022-04-28  7:35   ` Maxim Levitsky
2022-04-28 13:27     ` Maciej S. Szmigiero
2022-04-28 14:34       ` Maxim Levitsky [this message]
2022-04-28 15:04         ` Sean Christopherson
2022-04-28 16:33           ` Maciej S. Szmigiero
2022-04-23  2:14 ` [PATCH v2 03/11] KVM: SVM: Unwind "speculative" RIP advancement if INTn injection "fails" Sean Christopherson
2022-04-23  2:14 ` [PATCH v2 04/11] KVM: SVM: Stuff next_rip on emulated INT3 injection if NRIPS is supported Sean Christopherson
2022-04-23  2:14 ` [PATCH v2 05/11] KVM: SVM: Re-inject INT3/INTO instead of retrying the instruction Sean Christopherson
2022-04-25 22:59   ` Maciej S. Szmigiero
2022-04-28  9:37   ` Maxim Levitsky
2022-04-28 13:36     ` Maciej S. Szmigiero
2022-04-28 14:25       ` Sean Christopherson
2022-04-23  2:14 ` [PATCH v2 06/11] KVM: SVM: Re-inject INTn instead of retrying the insn on "failure" Sean Christopherson
2022-04-23  2:14 ` [PATCH v2 07/11] KVM: x86: Trace re-injected exceptions Sean Christopherson
2022-04-28  9:48   ` Maxim Levitsky
2022-04-23  2:14 ` [PATCH v2 08/11] KVM: x86: Print error code in exception injection tracepoint iff valid Sean Christopherson
2022-04-28  9:49   ` Maxim Levitsky
2022-04-23  2:14 ` [PATCH v2 09/11] KVM: x86: Differentiate Soft vs. Hard IRQs vs. reinjected in tracepoint Sean Christopherson
2022-04-25 22:59   ` Maciej S. Szmigiero
2022-04-23  2:14 ` [PATCH v2 10/11] KVM: selftests: nSVM: Add svm_nested_soft_inject_test Sean Christopherson
2022-04-25 23:00   ` Maciej S. Szmigiero
2022-04-23  2:14 ` [PATCH v2 11/11] KVM: SVM: Drop support for CPUs without NRIPS (NextRIP Save) support Sean Christopherson
2022-04-24  9:34   ` Maxim Levitsky
2022-04-25 23:00   ` Maciej S. Szmigiero
2022-04-25 23:01 ` [PATCH v2 00/11] KVM: SVM: Fix soft int/ex re-injection Maciej S. Szmigiero
2022-04-27 18:21   ` Maciej S. Szmigiero

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