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From: Chenyi Qiang <chenyi.qiang@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Xiaoyao Li <xiaoyao.li@intel.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 4/5] KVM: MMU: Add support for PKS emulation
Date: Tue, 3 Aug 2021 16:52:52 +0800	[thread overview]
Message-ID: <9f1edbcb-cba3-015f-bec5-8f9873245d09@intel.com> (raw)
In-Reply-To: <fd1b39b1-ce99-3626-b502-eb1324001163@redhat.com>



On 7/30/2021 1:45 AM, Paolo Bonzini wrote:
> On 29/07/21 19:25, Sean Christopherson wrote:
>>> -        unsigned int cr4_pke:1;
>>> +        unsigned int cr4_pkr:1;
>> Smushing these together will not work, as this code (from below)
>>
>>> -     ext.cr4_pke = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE);
>>> +     ext.cr4_pkr = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE) ||
>>> +                   !!kvm_read_cr4_bits(vcpu, X86_CR4_PKS);
>> will generate the same mmu_role for CR4.PKE=0,PKS=1 and 
>> CR4.PKE=1,PKS=1 (and
>> other combinations).  I.e. KVM will fail to reconfigure the MMU and 
>> thus skip
>> update_pkr_bitmask() if the guest toggles PKE or PKS while the other 
>> PK* bit is set.
>>
> 
> I'm also not sure why there would be issues in just using cr4_pks.
> 

Will split out the pke and pks.

Thanks
Chenyi

> Paolo
> 

  reply	other threads:[~2021-08-03  8:52 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-05  8:37 [PATCH v4 0/5] KVM: PKS Virtualization support Chenyi Qiang
2021-02-05  8:37 ` [PATCH v4 1/5] KVM: VMX: Introduce PKS VMCS fields Chenyi Qiang
2021-02-05  8:37 ` [PATCH v4 2/5] KVM: X86: Expose PKS to guest Chenyi Qiang
2021-02-05  9:23   ` Paolo Bonzini
2021-02-05  9:25   ` Paolo Bonzini
2021-02-05  9:56     ` Borislav Petkov
2021-02-05 10:10       ` Paolo Bonzini
2021-02-05 11:29         ` Thomas Gleixner
2021-02-05 11:51           ` Paolo Bonzini
2021-07-29 16:44   ` Sean Christopherson
2021-08-03  8:50     ` Chenyi Qiang
2021-02-05  8:37 ` [PATCH v4 3/5] KVM: MMU: Rename the pkru to pkr Chenyi Qiang
2021-02-05  8:37 ` [PATCH v4 4/5] KVM: MMU: Add support for PKS emulation Chenyi Qiang
2021-02-05  9:20   ` Paolo Bonzini
2021-07-29 17:25   ` Sean Christopherson
2021-07-29 17:45     ` Paolo Bonzini
2021-08-03  8:52       ` Chenyi Qiang [this message]
2021-02-05  8:37 ` [PATCH v4 5/5] KVM: VMX: Enable PKS for nested VM Chenyi Qiang
2021-02-05  9:24 ` [PATCH v4 0/5] KVM: PKS Virtualization support Paolo Bonzini

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