From: Sean Christopherson <seanjc@google.com>
To: Weijiang Yang <weijiang.yang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Maxim Levitsky <mlevitsk@redhat.com>
Subject: Re: [PATCH 6/9] KVM: x86: Update guest cpu_caps at runtime for dynamic CPUID-based features
Date: Thu, 16 Nov 2023 14:19:10 -0800 [thread overview]
Message-ID: <ZVaVXtKU1nxjFkrw@google.com> (raw)
In-Reply-To: <bc2534fe-ade3-496e-a1be-bb2196fb2003@intel.com>
On Thu, Nov 16, 2023, Weijiang Yang wrote:
> On 11/11/2023 7:55 AM, Sean Christopherson wrote:
> > static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *entries,
> > int nent)
> > {
> > struct kvm_cpuid_entry2 *best;
> > + struct kvm_vcpu *caps = vcpu;
> > +
> > + /*
> > + * Don't update vCPU capabilities if KVM is updating CPUID entries that
> > + * are coming in from userspace!
> > + */
> > + if (entries != vcpu->arch.cpuid_entries)
> > + caps = NULL;
>
> Nit, why here we use caps instead of vcpu? Looks a bit weird.
See my response to Robert: https://lore.kernel.org/all/9395d416-cc5c-536d-641e-ffd971b682d1@gmail.com
> > best = cpuid_entry2_find(entries, nent, 1, KVM_CPUID_INDEX_NOT_SIGNIFICANT);
> > - if (best) {
> > - /* Update OSXSAVE bit */
> > - if (boot_cpu_has(X86_FEATURE_XSAVE))
> > - cpuid_entry_change(best, X86_FEATURE_OSXSAVE,
> > +
> > + if (boot_cpu_has(X86_FEATURE_XSAVE))
> > + kvm_update_feature_runtime(caps, best, X86_FEATURE_OSXSAVE,
> > kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE));
> > - cpuid_entry_change(best, X86_FEATURE_APIC,
> > - vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE);
> > + kvm_update_feature_runtime(caps, best, X86_FEATURE_APIC,
> > + vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE);
> > - if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT))
> > - cpuid_entry_change(best, X86_FEATURE_MWAIT,
> > - vcpu->arch.ia32_misc_enable_msr &
> > - MSR_IA32_MISC_ENABLE_MWAIT);
> > - }
> > + if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT))
> > + kvm_update_feature_runtime(caps, best, X86_FEATURE_MWAIT,
> > + vcpu->arch.ia32_misc_enable_msr & MSR_IA32_MISC_ENABLE_MWAIT);
>
> > 80 characters?
Hmm, yeah, I suppose.
next prev parent reply other threads:[~2023-11-16 22:19 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-10 23:55 [PATCH 0/9] KVM: x86: Replace governed features with guest cpu_caps Sean Christopherson
2023-11-10 23:55 ` [PATCH 1/9] KVM: x86: Rename "governed features" helpers to use "guest_cpu_cap" Sean Christopherson
2023-11-19 17:08 ` Maxim Levitsky
2023-11-21 3:20 ` Chao Gao
2023-11-10 23:55 ` [PATCH 2/9] KVM: x86: Replace guts of "goverened" features with comprehensive cpu_caps Sean Christopherson
2023-11-14 9:12 ` Binbin Wu
2023-11-19 17:22 ` Maxim Levitsky
2023-11-28 1:24 ` Sean Christopherson
2023-11-10 23:55 ` [PATCH 3/9] KVM: x86: Initialize guest cpu_caps based on guest CPUID Sean Christopherson
2023-11-16 3:16 ` Yang, Weijiang
2023-11-16 22:29 ` Sean Christopherson
2023-11-17 8:33 ` Yang, Weijiang
2023-11-21 3:10 ` Yuan Yao
2023-11-19 17:32 ` Maxim Levitsky
2023-12-01 1:51 ` Sean Christopherson
2023-12-21 16:59 ` Maxim Levitsky
2024-01-05 2:13 ` Sean Christopherson
2024-01-12 0:44 ` Sean Christopherson
2023-11-10 23:55 ` [PATCH 4/9] KVM: x86: Avoid double CPUID lookup when updating MWAIT at runtime Sean Christopherson
2023-11-19 17:33 ` Maxim Levitsky
2023-11-10 23:55 ` [PATCH 5/9] KVM: x86: Drop unnecessary check that cpuid_entry2_find() returns right leaf Sean Christopherson
2023-11-19 17:33 ` Maxim Levitsky
2023-11-10 23:55 ` [PATCH 6/9] KVM: x86: Update guest cpu_caps at runtime for dynamic CPUID-based features Sean Christopherson
2023-11-13 8:03 ` Robert Hoo
2023-11-14 13:48 ` Sean Christopherson
2023-11-15 1:59 ` Robert Hoo
2023-11-15 15:09 ` Sean Christopherson
2023-11-17 1:28 ` Robert Hoo
2023-11-16 2:24 ` Yang, Weijiang
2023-11-16 22:19 ` Sean Christopherson [this message]
2023-11-19 17:35 ` Maxim Levitsky
2023-11-24 6:33 ` Xu Yilun
2023-11-28 0:43 ` Sean Christopherson
2023-11-28 5:13 ` Xu Yilun
2023-11-10 23:55 ` [PATCH 7/9] KVM: x86: Shuffle code to prepare for dropping guest_cpuid_has() Sean Christopherson
2023-11-19 17:35 ` Maxim Levitsky
2023-11-10 23:55 ` [PATCH 8/9] KVM: x86: Replace all guest CPUID feature queries with cpu_caps check Sean Christopherson
2023-11-19 17:35 ` Maxim Levitsky
2023-11-10 23:55 ` [PATCH 9/9] KVM: x86: Restrict XSAVE in cpu_caps based on KVM capabilities Sean Christopherson
2023-11-19 17:36 ` Maxim Levitsky
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