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AJvYcCUCuxUJvqHjMt9/8yOpILqPubvCt18ky2gdmkDxcIyoeZQZdXWtK8hhfuEVh9vAwyvNL/E=@vger.kernel.org X-Gm-Message-State: AOJu0Ywew2ZMouvSc3RRPnnI/85gFR5FdBEs++PcYAdO2RZgp39JbIe2 zkaHY1t/JZxWAlrlWUzixJtYXkvb8ndHGmHKesNRT2Rqwe5bjeVCCjwUegF+3s7xqwKq9bdi8DO XxgWxnw== X-Google-Smtp-Source: AGHT+IHX8Jy0M1JBFk6lQsQKZTo86YiB/IwGKKkwJEOCBeRFMvDtz7vI0OgXa2nqG5b1DW86HcKEO02ZVYI= X-Received: from pjbbb15.prod.google.com ([2002:a17:90b:8f:b0:32e:b87b:6c84]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:5824:b0:32d:fd14:600b with SMTP id 98e67ed59e1d1-339eda5e097mr44148257a91.7.1760477071924; Tue, 14 Oct 2025 14:24:31 -0700 (PDT) Date: Tue, 14 Oct 2025 14:24:30 -0700 In-Reply-To: <8b1f31fec081c7e570ddec93477dd719638cc363.camel@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251013062515.3712430-1-nikunj@amd.com> <20251013062515.3712430-5-nikunj@amd.com> <30dd3c26d3e3f6372b41c0d7741abedb5b51d57d.camel@intel.com> <8b1f31fec081c7e570ddec93477dd719638cc363.camel@intel.com> Message-ID: Subject: Re: [PATCH v4 4/7] KVM: x86: Move nested CPU dirty logging logic to common code From: Sean Christopherson To: Kai Huang Cc: "pbonzini@redhat.com" , "nikunj@amd.com" , "thomas.lendacky@amd.com" , "kvm@vger.kernel.org" , "joao.m.martins@oracle.com" , "santosh.shukla@amd.com" , "bp@alien8.de" Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Tue, Oct 14, 2025, Kai Huang wrote: > On Tue, 2025-10-14 at 11:34 +0000, Huang, Kai wrote: > > > =C2=A0=20 > > > +static void kvm_vcpu_update_cpu_dirty_logging(struct kvm_vcpu *vcpu) > > > +{ > > > + if (WARN_ON_ONCE(!enable_pml)) > > > + return; > >=20 > > Nit:=C2=A0=20 > >=20 > > Since kvm_mmu_update_cpu_dirty_logging() checks kvm- > > > arch.cpu_dirty_log_size to determine whether PML is enabled, maybe it= 's > > better to check vcpu->kvm.arch.cpu_dirty_log_size here too to make them > > consistent. >=20 > After second thought, I think we should just change to checking the vcpu- > >kvm.arch.cpu_dirty_log_size. +1 > > Anyway, the intention of this patch is moving code out of VMX to x86, s= o > > if needed, perhaps we can do the change in another patch. > >=20 > > Btw, now with 'enable_pml' also being moved to x86 common, both > > 'enable_pml' and 'kvm->arch.cpu_dirty_log_size' can be used to determin= e > > whether KVM has enabled PML.=C2=A0 It's kinda redundant, but I guess it= 's fine. >=20 > If we change to check cpu_dirty_log_size here, the x86 common code won't > use 'enable_pml' anymore and I think we can just get rid of that patch. >=20 > Sean, do you have any preference? Definitely check cpu_dirty_log_size. It's more precise (TDX doesn't (yet) = support PML), avoids the export, and hopefully will yield more consistent code.