Subject: Re: [PATCH v2 0/4] KVM: VMX: enable LBR virtualization
To: Jian Zhou <jianjay.zhou@huawei.com>, kvm@vger.kernel.org, gleb@kernel.org,
        tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org,
        linux-kernel@vger.kernel.org
References: <1445591718-5720-1-git-send-email-jianjay.zhou@huawei.com>
Cc: herongguang.he@huawei.com, zhang.zhanghailiang@huawei.com,
        weidong.huang@huawei.com, peter.huangpeng@huawei.com
From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <56435D76.7080402@redhat.com>
Date: Wed, 11 Nov 2015 16:23:34 +0100
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On 23/10/2015 11:15, Jian Zhou wrote:
> Changelog in v2:
>   (1) move the implementation into vmx.c
>   (2) migraton is supported
>   (3) add arrays in kvm_vcpu_arch struct to save/restore
>       LBR MSRs at vm exit/entry time.
>   (4) add a parameter of kvm_intel module to permanently
>       disable LBRV
>   (5) table of supported CPUs is reorgnized, LBRV
>       can be enabled or not according to the guest CPUID
> 
> Jian Zhou (4):
>   KVM: X86: Add arrays to save/restore LBR MSRs
>   KVM: X86: LBR MSRs of supported CPU types
>   KVM: X86: Migration is supported
>   KVM: VMX: details of LBR virtualization implementation
> 
>  arch/x86/include/asm/kvm_host.h  |  26 ++++-
>  arch/x86/include/asm/msr-index.h |  26 ++++-
>  arch/x86/kvm/vmx.c               | 245 +++++++++++++++++++++++++++++++++++++++
>  arch/x86/kvm/x86.c               |  88 ++++++++++++--
>  4 files changed, 366 insertions(+), 19 deletions(-)

Thanks, this looks better!

The reason why it took me so long to review it, is that I wanted to
understand what happens if you're running this on CPU model x but using
CPU model y for the guest.  I still haven't grokked that fully, so I'll
apply your patches locally and play with them.

In the meanwhile, feel free to send v3 with: 1) the tweak I suggested to
patch 3; 2) the fix for the problem that the buildbot reported on patch 1.

Paolo
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