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[34.125.103.223]) by smtp.gmail.com with ESMTPSA id y20-20020a170902e19400b0016c35b21901sm9669785pla.195.2022.07.25.16.23.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Jul 2022 16:23:57 -0700 (PDT) Date: Mon, 25 Jul 2022 16:23:52 -0700 From: David Matlack To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed , Mingwei Zhang , Ben Gardon Subject: Re: [PATCH v2 5/6] KVM: x86/mmu: Add helper to convert SPTE value to its shadow page Message-ID: References: <20220723012325.1715714-1-seanjc@google.com> <20220723012325.1715714-6-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220723012325.1715714-6-seanjc@google.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Sat, Jul 23, 2022 at 01:23:24AM +0000, Sean Christopherson wrote: > Add a helper to convert a SPTE to its shadow page to deduplicate a > variety of flows and hopefully avoid future bugs, e.g. if KVM attempts to > get the shadow page for a SPTE without dropping high bits. > > Opportunistically add a comment in mmu_free_root_page() documenting why > it treats the root HPA as a SPTE. > > No functional change intended. > > Signed-off-by: Sean Christopherson > --- [...] > --- a/arch/x86/kvm/mmu/spte.h > +++ b/arch/x86/kvm/mmu/spte.h > @@ -207,6 +207,23 @@ static inline int spte_index(u64 *sptep) > */ > extern u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask; > > +static inline struct kvm_mmu_page *to_shadow_page(hpa_t shadow_page) > +{ > + struct page *page = pfn_to_page((shadow_page) >> PAGE_SHIFT); > + > + return (struct kvm_mmu_page *)page_private(page); > +} > + > +static inline struct kvm_mmu_page *spte_to_sp(u64 spte) > +{ > + return to_shadow_page(spte & SPTE_BASE_ADDR_MASK); > +} spte_to_sp() and sptep_to_sp() are a bit hard to differentiate visually. Maybe spte_to_child_sp() or to_child_sp()? > + > +static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep) > +{ > + return to_shadow_page(__pa(sptep)); > +} > + > static inline bool is_mmio_spte(u64 spte) > { > return (spte & shadow_mmio_mask) == shadow_mmio_value && > diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h > index c163f7cc23ca..d3714200b932 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.h > +++ b/arch/x86/kvm/mmu/tdp_mmu.h > @@ -5,6 +5,8 @@ > > #include > > +#include "spte.h" > + > hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu); > > __must_check static inline bool kvm_tdp_mmu_get_root(struct kvm_mmu_page *root) > -- > 2.37.1.359.gd136c6c3e2-goog >