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 2/7] KVM: VMX: Expose IA32_PKRS MSR
Date: Tue, 26 Jan 2021 19:01:55 +0100 [thread overview]
Message-ID: <62f5f5ba-cbe9-231d-365a-80a656208e37@redhat.com> (raw)
In-Reply-To: <20200807084841.7112-3-chenyi.qiang@intel.com>
On 07/08/20 10:48, Chenyi Qiang wrote:
> +{
> + struct vcpu_vmx *vmx = to_vmx(vcpu);
> + unsigned long *msr_bitmap = vmx->vmcs01.msr_bitmap;
> + bool pks_supported = guest_cpuid_has(vcpu, X86_FEATURE_PKS);
> +
> + /*
> + * set intercept for PKRS when the guest doesn't support pks
> + */
> + vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_PKRS, MSR_TYPE_RW, !pks_supported);
> +
> + if (pks_supported) {
> + vm_entry_controls_setbit(vmx, VM_ENTRY_LOAD_IA32_PKRS);
> + vm_exit_controls_setbit(vmx, VM_EXIT_LOAD_IA32_PKRS);
> + } else {
> + vm_entry_controls_clearbit(vmx, VM_ENTRY_LOAD_IA32_PKRS);
> + vm_exit_controls_clearbit(vmx, VM_EXIT_LOAD_IA32_PKRS);
> + }
Is the guest expected to do a lot of reads/writes to the MSR (e.g. at
every context switch)?
Even if this is the case, the MSR intercepts and the entry/exit controls
should only be done if CR4.PKS=1. If the guest does not use PKS, KVM
should behave as if these patches did not exist.
Paolo
next prev parent reply other threads:[~2021-01-27 13:16 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 [this message]
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
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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