From: Sean Christopherson <seanjc@google.com>
To: Wei W Wang <wei.w.wang@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>
Subject: Re: [PATCH 1/4] KVM: x86: Add a struct to consolidate host values, e.g. EFER, XCR0, etc...
Date: Thu, 25 Apr 2024 07:47:29 -0700 [thread overview]
Message-ID: <ZiptAV51VcTEhqgY@google.com> (raw)
In-Reply-To: <DS0PR11MB6373C82CB77354EFD779E0C3DC172@DS0PR11MB6373.namprd11.prod.outlook.com>
On Thu, Apr 25, 2024, Wei W Wang wrote:
> On Thursday, April 25, 2024 10:10 PM, Sean Christopherson wrote:
> > We should shorten the name to arch_caps, but I don't think that's a net
> > positive, e.g. unless we do a bulk rename, it'd diverge from several other
> > functions/variables, and IMO it would be less obvious that the field holds
> > MSR_IA32_ARCH_CAPABILITIES.
>
> Yeah, the above isn't nice and no need to do bulk rename.
> We could just shorten it here, e.g.:
Works for me.
> > > > @@ -325,11 +332,8 @@ int x86_emulate_instruction(struct kvm_vcpu
> > > > *vcpu, gpa_t cr2_or_gpa,
> > > > int emulation_type, void *insn, int insn_len);
> > fastpath_t
> > > > handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu);
> > > >
> > > > -extern u64 host_xcr0;
> > > > -extern u64 host_xss;
> > > > -extern u64 host_arch_capabilities;
> > > > -
> > > > extern struct kvm_caps kvm_caps;
> > > > +extern struct kvm_host_values kvm_host;
> > >
> > > Have you considered merging the kvm_host_values and kvm_caps into one
> > > unified structure?
> >
> > No really. I don't see any benefit, only the downside of having to come up
> > with a name that is intuitive when reading code related to both.
>
> I thought the two structures perform quite similar jobs and most of the fields in
> kvm_cap, e.g. has_tsc_control, supported_perf_cap, could also be interpreted
> as host values?
No, kvm_caps is filtered and/or generated information, e.g. supported_perf_cap
and supported_xss incorporate host/hardware support, but they also incorporate
KVM's own capabilities.
kvm_host holds pure, unadultered host values.
XSS is a perfect example. If we shoved the host value in kvm_caps, then we'd
have kvm_caps.supported_xss and kvm_caps.xss, which would be incredibly confusing.
So then we'd need to rename it to kvm_caps.host_xss, which is also confusing,
just less so, and also results in a longer name with no added value.
next prev parent reply other threads:[~2024-04-25 14:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-23 22:15 [PATCH 0/4] KVM: x86: Collect host state snapshots into a struct Sean Christopherson
2024-04-23 22:15 ` [PATCH 1/4] KVM: x86: Add a struct to consolidate host values, e.g. EFER, XCR0, etc Sean Christopherson
2024-04-25 11:29 ` Wang, Wei W
2024-04-25 14:10 ` Sean Christopherson
2024-04-25 14:37 ` Wang, Wei W
2024-04-25 14:47 ` Sean Christopherson [this message]
2024-04-23 22:15 ` [PATCH 2/4] KVM: SVM: Use KVM's snapshot of the host's XCR0 for SEV-ES host state Sean Christopherson
2024-04-23 22:15 ` [PATCH 3/4] KVM: x86/mmu: Snapshot shadow_phys_bits when kvm.ko is loaded Sean Christopherson
2024-04-23 22:15 ` [PATCH 4/4] KVM: x86: Move shadow_phys_bits into "kvm_host", as "maxphyaddr" Sean Christopherson
2024-04-25 11:17 ` [PATCH 0/4] KVM: x86: Collect host state snapshots into a struct Wang, Wei W
2024-04-25 14:24 ` Sean Christopherson
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