From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
yang.zhang.wz@gmail.com, feng.wu@intel.com, mst@redhat.com
Subject: Re: [PATCH 2/5] KVM: x86: do not scan IRR twice on APICv vmentry
Date: Thu, 3 Nov 2016 19:07:54 +0100 [thread overview]
Message-ID: <20161103180753.GF7771@potion> (raw)
In-Reply-To: <af052add-55c9-d314-3d21-ac32e2cfbb82@redhat.com>
2016-11-03 17:00+0100, Paolo Bonzini:
> On 03/11/2016 16:03, Radim Krčmář wrote:
>> 2016-11-03 14:30+0100, Paolo Bonzini:
>>> On 26/10/2016 21:59, Radim Krčmář wrote:
>>>> 2016-10-14 20:21+0200, Paolo Bonzini:
>>>>> Calling apic_find_highest_irr results in IRR being scanned twice,
>>>>> once in vmx_sync_pir_from_irr and once in apic_search_irr. Change
>>>>> sync_pir_from_irr to do the RVI write and kvm_apic_update_irr to
>>>>> compute the new RVI on the fly.
>>>>>
>>>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>>>> ---
>>>>
>>>> Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
>>>
>>> Nope, this breaks nested VMX exit on external interrupt. For now I'm
>>> testing only patch 1 and will push that one only to kvm/next.
Which hypervisor is being nested?
>> Hm, does it also happen with this change?
>
> Probably not but I wanted to understand why. :)
Yeah, I'm also looking forward to knowing the funny coincidence.
I think a bug is likely for hypervisors that don't enable
PIN_BASED_EXT_INTR_MASK. The bug would trigger when
kvm_cpu_has_interrupt() in vmx_check_nested_events() in
kvm_arch_vcpu_runnable() queues the interrupt ...
but I didn't see how this would have caused a problem. :)
next prev parent reply other threads:[~2016-11-03 18:07 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-14 18:21 [PATCH 0/5] KVM: x86: cleanup and minimal speedup for APICv Paolo Bonzini
2016-10-14 18:21 ` [PATCH 1/5] KVM: x86: avoid atomic operations on APICv vmentry Paolo Bonzini
2016-10-14 18:50 ` Nadav Amit
2016-10-14 18:56 ` Paolo Bonzini
2016-10-14 19:44 ` Nadav Amit
2016-10-15 7:47 ` Paolo Bonzini
2016-10-16 2:29 ` Michael S. Tsirkin
2016-10-19 11:45 ` Paul E. McKenney
2016-10-26 21:50 ` Michael S. Tsirkin
2016-10-16 3:21 ` Michael S. Tsirkin
2016-10-17 11:07 ` Paolo Bonzini
2016-10-26 19:53 ` Radim Krčmář
2016-10-26 21:42 ` Michael S. Tsirkin
2016-10-27 16:44 ` Radim Krčmář
2016-10-27 16:51 ` Michael S. Tsirkin
2016-10-27 17:06 ` Radim Krčmář
2016-10-28 9:39 ` Paolo Bonzini
2016-10-28 22:04 ` Michael S. Tsirkin
2016-10-14 18:21 ` [PATCH 2/5] KVM: x86: do not scan IRR twice " Paolo Bonzini
2016-10-18 6:04 ` Wanpeng Li
2016-10-26 19:59 ` Radim Krčmář
2016-11-03 13:30 ` Paolo Bonzini
2016-11-03 13:53 ` Michael S. Tsirkin
2016-11-03 16:01 ` Paolo Bonzini
2016-11-03 15:03 ` Radim Krčmář
2016-11-03 16:00 ` Paolo Bonzini
2016-11-03 18:07 ` Radim Krčmář [this message]
2016-11-03 18:18 ` Paolo Bonzini
2016-11-03 18:29 ` Radim Krčmář
2016-11-03 20:16 ` Radim Krčmář
2016-11-04 9:38 ` Paolo Bonzini
2016-10-14 18:21 ` [PATCH 3/5] KVM: x86: do not use KVM_REQ_EVENT for APICv interrupt injection Paolo Bonzini
2016-10-26 20:05 ` Radim Krčmář
2016-10-14 18:21 ` [PATCH 4/5] KVM: x86: remove unnecessary sync_pir_to_irr Paolo Bonzini
2016-10-26 20:28 ` Radim Krčmář
2016-10-14 18:21 ` [PATCH 5/5] KVM: vmx: clear pending interrupts on KVM_SET_LAPIC Paolo Bonzini
2016-10-26 20:08 ` Radim Krčmář
2016-10-26 21:52 ` [PATCH 0/5] KVM: x86: cleanup and minimal speedup for APICv Michael S. Tsirkin
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