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From: Jim Mattson <jmattson@google.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Joerg Roedel <joro@8bytes.org>, kvm list <kvm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Oliver Upton <oupton@google.com>, Peter Shier <pshier@google.com>
Subject: Re: [PATCH 01/13] KVM: nVMX: Preserve exception priority irrespective of exiting behavior
Date: Tue, 28 Apr 2020 11:54:35 -0700	[thread overview]
Message-ID: <CALMp9eRD9py=N9hDSon5GPzuiZw1Z+3xHv9umu1_qKzWczz0PA@mail.gmail.com> (raw)
In-Reply-To: <20200423022550.15113-2-sean.j.christopherson@intel.com>

On Wed, Apr 22, 2020 at 7:26 PM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> Short circuit vmx_check_nested_events() if an exception is pending and
> needs to be injected into L2, priority between coincident events is not
> dependent on exiting behavior.  This fixes a bug where a single-step #DB
> that is not intercepted by L1 is incorrectly dropped due to servicing a
> VMX Preemption Timer VM-Exit.
>
> Injected exceptions also need to be blocked if nested VM-Enter is
> pending or an exception was already injected, otherwise injecting the
> exception could overwrite an existing event injection from L1.
> Technically, this scenario should be impossible, i.e. KVM shouldn't
> inject its own exception during nested VM-Enter.  This will be addressed
> in a future patch.
>
> Note, event priority between SMI, NMI and INTR is incorrect for L2, e.g.
> SMI should take priority over VM-Exit on NMI/INTR, and NMI that is
> injected into L2 should take priority over VM-Exit INTR.  This will also
> be addressed in a future patch.
>
> Fixes: b6b8a1451fc4 ("KVM: nVMX: Rework interception of IRQs and NMIs")
> Reported-by: Jim Mattson <jmattson@google.com>
> Cc: Oliver Upton <oupton@google.com>
> Cc: Peter Shier <pshier@google.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>

  reply	other threads:[~2020-04-28 18:54 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-23  2:25 [PATCH 00/13] KVM: x86: Event fixes and cleanup Sean Christopherson
2020-04-23  2:25 ` [PATCH 01/13] KVM: nVMX: Preserve exception priority irrespective of exiting behavior Sean Christopherson
2020-04-28 18:54   ` Jim Mattson [this message]
2020-04-28 20:07     ` Oliver Upton
2020-04-23  2:25 ` [PATCH 02/13] KVM: nVMX: Open a window for pending nested VMX preemption timer Sean Christopherson
2020-04-28 21:39   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 03/13] KVM: x86: Set KVM_REQ_EVENT if run is canceled with req_immediate_exit set Sean Christopherson
2020-04-28 21:41   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 04/13] KVM: x86: Make return for {interrupt_nmi}_allowed() a bool instead of int Sean Christopherson
2020-04-28 21:42   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 05/13] KVM: nVMX: Move nested_exit_on_nmi() to nested.h Sean Christopherson
2020-04-28 21:44   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 06/13] KVM: nVMX: Report NMIs as allowed when in L2 and Exit-on-NMI is set Sean Christopherson
2020-04-28 21:46   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 07/13] KVM: VMX: Split out architectural interrupt/NMI blocking checks Sean Christopherson
2020-04-28 21:57   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 08/13] KVM: nVMX: Preserve IRQ/NMI priority irrespective of exiting behavior Sean Christopherson
2020-04-28 21:58   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 09/13] KVM: nVMX: Prioritize SMI over nested IRQ/NMI Sean Christopherson
2020-04-28 22:04   ` Jim Mattson
2020-04-28 22:59     ` Sean Christopherson
2020-04-28 23:16       ` Jim Mattson
2020-04-29 14:50         ` Sean Christopherson
2020-04-29 20:06           ` Sean Christopherson
2020-04-28 23:23       ` Jim Mattson
2020-04-23  2:25 ` [PATCH 10/13] KVM: x86: WARN on injected+pending exception even in nested case Sean Christopherson
2020-04-28 22:05   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 11/13] KVM: VMX: Use vmx_interrupt_blocked() directly from vmx_handle_exit() Sean Christopherson
2020-04-28 22:07   ` Jim Mattson
2020-04-23  2:25 ` [PATCH 12/13] KVM: x86: Replace late check_nested_events() hack with more precise fix Sean Christopherson
2020-04-23 11:00   ` Paolo Bonzini
2020-04-28 22:12   ` Jim Mattson
2020-04-28 22:20     ` Sean Christopherson
2020-04-29  8:36       ` Paolo Bonzini
2020-04-29 16:45         ` Sean Christopherson
2020-04-29 16:58           ` Paolo Bonzini
2020-04-29 17:07             ` Sean Christopherson
2020-04-23  2:25 ` [PATCH 13/13] KVM: VMX: Use vmx_get_rflags() to query RFLAGS in vmx_interrupt_blocked() Sean Christopherson
2020-04-28 22:13   ` Jim Mattson

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