From: Sean Christopherson <seanjc@google.com>
To: Xiaoyao Li <xiaoyao.li@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Like Xu <like.xu.linux@gmail.com>
Subject: Re: [RFC PATCH 3/3] KVM: x86: Disallow writes to immutable feature MSRs after KVM_RUN
Date: Wed, 10 Aug 2022 14:45:39 +0000 [thread overview]
Message-ID: <YvPEk4tnvajOfjBl@google.com> (raw)
In-Reply-To: <40c9ecc1-e223-160b-4939-07e4f7200781@intel.com>
On Wed, Aug 10, 2022, Xiaoyao Li wrote:
> On 8/6/2022 1:29 AM, Sean Christopherson wrote:
> > @@ -2136,6 +2156,23 @@ static int do_get_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
> > static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
> > {
> > + u64 val;
> > +
> > + /*
> > + * Disallow writes to immutable feature MSRs after KVM_RUN. KVM does
> > + * not support modifying the guest vCPU model on the fly, e.g. changing
> > + * the nVMX capabilities while L2 is running is nonsensical. Ignore
> > + * writes of the same value, e.g. to allow userspace to blindly stuff
> > + * all MSRs when emulating RESET.
> > + */
> > + if (vcpu->arch.last_vmentry_cpu != -1 &&
>
> can we extract "vcpu->arch.last_vmentry_cpu != -1" into a function like
> kvm_vcpu_has_runned() ?
Ya, a helper is in order. I'll add a patch in the next version.
next prev parent reply other threads:[~2022-08-10 14:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-05 17:29 [RFC PATCH 0/3] KVM: x86: Disallow writes to feature MSRs post-KVM_RUN Sean Christopherson
2022-08-05 17:29 ` [RFC PATCH 1/3] KVM: x86: Add macros to track first...last VMX feature MSRs Sean Christopherson
2022-08-05 17:29 ` [RFC PATCH 2/3] KVM: x86: Generate set of VMX feature MSRs using first/last definitions Sean Christopherson
2022-08-10 12:52 ` Paolo Bonzini
2022-08-10 14:40 ` Sean Christopherson
2022-08-10 19:16 ` Paolo Bonzini
2022-08-05 17:29 ` [RFC PATCH 3/3] KVM: x86: Disallow writes to immutable feature MSRs after KVM_RUN Sean Christopherson
2022-08-10 6:29 ` Xiaoyao Li
2022-08-10 14:45 ` Sean Christopherson [this message]
2022-08-10 12:52 ` [RFC PATCH 0/3] KVM: x86: Disallow writes to feature MSRs post-KVM_RUN Paolo Bonzini
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