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From: Paolo Bonzini <pbonzini@redhat.com>
To: Chenyi Qiang <chenyi.qiang@intel.com>,
	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>,
	Xiaoyao Li <xiaoyao.li@intel.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 5/7] KVM: MMU: Add support for PKS emulation
Date: Wed, 27 Jan 2021 09:37:12 +0100	[thread overview]
Message-ID: <ed72302d-2644-75d4-f219-7855cf0430df@redhat.com> (raw)
In-Reply-To: <3e38051e-b341-66b9-5e2e-2c3f26d3ff70@intel.com>

On 27/01/21 04:00, Chenyi Qiang wrote:
>>
>>>
>>>          if (pte_access & PT_USER_MASK)
>>>              pkr_bits = (vcpu->arch.pkru >> (pte_pkey * 2)) & 3;
>>> +        else if (!kvm_get_msr(vcpu, MSR_IA32_PKRS, &pkrs))
>>> +            pkr_bits = (pkrs >> (pte_pkey * 2)) & 3;
>>
>> You should be able to always use vcpu->arch.pkrs here.  So
>>
>> pkr = pte_access & PT_USER_MASK ? vcpu->arch.pkru : vcpu->arch.pkrs;
>> pkr_bits = (pkr >> pte_pkey * 2) & 3;
>>
> Concerning vcpu->arch.pkrs would be the only use case in current 
> submitted patches, is it still necessary to shadow it?

Yes, please do.  kvm_get_msr is pretty slow, and the code becomes 
simpler too.

Paolo


  reply	other threads:[~2021-01-27  8:41 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-07  8:48 [RFC 0/7] KVM: PKS Virtualization support Chenyi Qiang
2020-08-07  8:48 ` [RFC 1/7] KVM: VMX: Introduce PKS VMCS fields Chenyi Qiang
2020-08-10 23:17   ` Jim Mattson
2020-08-07  8:48 ` [RFC 2/7] KVM: VMX: Expose IA32_PKRS MSR Chenyi Qiang
2020-08-12 21:21   ` Jim Mattson
2020-08-13  5:42     ` Chenyi Qiang
2020-08-13 17:31       ` Jim Mattson
2020-08-18  7:27         ` Chenyi Qiang
2020-08-18 18:23           ` Jim Mattson
2020-08-22  3:28             ` Sean Christopherson
2021-01-26 18:01   ` Paolo Bonzini
2021-01-27  7:55     ` Chenyi Qiang
2021-02-01  9:53     ` Chenyi Qiang
2021-02-01 10:05       ` Paolo Bonzini
2020-08-07  8:48 ` [RFC 3/7] KVM: MMU: Rename the pkru to pkr Chenyi Qiang
2021-01-26 18:16   ` Paolo Bonzini
2020-08-07  8:48 ` [RFC 4/7] KVM: MMU: Refactor pkr_mask to cache condition Chenyi Qiang
2021-01-26 18:16   ` Paolo Bonzini
2021-01-27  3:14     ` Chenyi Qiang
2020-08-07  8:48 ` [RFC 5/7] KVM: MMU: Add support for PKS emulation Chenyi Qiang
2021-01-26 18:23   ` Paolo Bonzini
2021-01-27  3:00     ` Chenyi Qiang
2021-01-27  8:37       ` Paolo Bonzini [this message]
2020-08-07  8:48 ` [RFC 6/7] KVM: X86: Expose PKS to guest and userspace Chenyi Qiang
2020-08-13 19:04   ` Jim Mattson
2020-08-14  2:33     ` Chenyi Qiang
2020-09-30  4:36     ` Sean Christopherson
2021-01-26 18:24       ` Paolo Bonzini
2021-01-26 19:56         ` Sean Christopherson
2021-01-26 20:05           ` Paolo Bonzini
2020-08-07  8:48 ` [RFC 7/7] KVM: VMX: Enable PKS for nested VM Chenyi Qiang
2020-08-11  0:05   ` Jim Mattson
2020-08-12 15:00     ` Sean Christopherson
2020-08-12 18:32       ` Jim Mattson
2020-08-13  4:52     ` Chenyi Qiang
2020-08-13 17:52       ` Jim Mattson
2020-08-14 10:07         ` Chenyi Qiang
2020-08-14 17:34           ` Jim Mattson

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