From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
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,
Oliver Upton <oupton@google.com>, Peter Shier <pshier@google.com>
Subject: [PATCH 03/13] KVM: x86: Set KVM_REQ_EVENT if run is canceled with req_immediate_exit set
Date: Wed, 22 Apr 2020 19:25:40 -0700 [thread overview]
Message-ID: <20200423022550.15113-4-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200423022550.15113-1-sean.j.christopherson@intel.com>
Re-request KVM_REQ_EVENT if vcpu_enter_guest() bails after processing
pending requests and an immediate exit was requested. This fixes a bug
where a pending event, e.g. VMX preemption timer, is delayed and/or lost
if the exit was deferred due to something other than a higher priority
_injected_ event, e.g. due to a pending nested VM-Enter. This bug only
affects the !injected case as kvm_x86_ops.cancel_injection() sets
KVM_REQ_EVENT to redo the injection, but that's purely serendipitous
behavior with respect to the deferred event.
Note, emulated preemption timer isn't the only event that can be
affected, it simply happens to be the only event where not re-requesting
KVM_REQ_EVENT is blatantly visible to the guest.
Fixes: f4124500c2c13 ("KVM: nVMX: Fully emulate preemption timer")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/x86.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ecd612807546..6af873b7e0ae 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8489,6 +8489,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
return r;
cancel_injection:
+ if (req_immediate_exit)
+ kvm_make_request(KVM_REQ_EVENT, vcpu);
kvm_x86_ops.cancel_injection(vcpu);
if (unlikely(vcpu->arch.apic_attention))
kvm_lapic_sync_from_vapic(vcpu);
--
2.26.0
next prev parent reply other threads:[~2020-04-23 2:27 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
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 ` Sean Christopherson [this message]
2020-04-28 21:41 ` [PATCH 03/13] KVM: x86: Set KVM_REQ_EVENT if run is canceled with req_immediate_exit set 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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