linux-kernel - Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv

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Date:   Thu, 22 Sep 2016 14:48:41 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     Radim Krčmář <rkrcmar@...hat.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        kvm <kvm@...r.kernel.org>, Wanpeng Li <wanpeng.li@...mail.com>,
        Wincy Van <fanwenyi0529@...il.com>,
        Yang Zhang <yang.zhang.wz@...il.com>
Subject: Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv

[...]
>
>> Btw, I heard from Tianyu from Intel, you said there was a x2apic bug
>> in kvm forum and the bug maybe in kvm, I guess I meet the same bug
>> when run a windows guest(server version of windows 7, 2008 or 2012) w/
>> x2apic enabled in guest and -machine q35,kernel_irqchip=spit -device
>> intel-iommu, intremap=on in the QEMU command line.
>
> Does it happen when you are running less than 8 VCPUs (max APIC ID < 8)?
> QEMU always enabled x2APIC support in IOMMU (EIME) even though it
> doesn't work under some configurations.

I'm digging  into the bug currently. :）

Regards,
Wanpeng Li