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[34.82.80.254]) by smtp.gmail.com with ESMTPSA id i13-20020a170902eb4d00b0015e8d4eb1b9sm7781773pli.3.2022.05.16.17.01.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 May 2022 17:01:20 -0700 (PDT) Date: Tue, 17 May 2022 00:01:17 +0000 From: David Matlack To: Lai Jiangshan Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Sean Christopherson , Lai Jiangshan , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" Subject: Re: [PATCH V2 3/7] KVM: X86/MMU: Link PAE root pagetable with its children Message-ID: References: <20220503150735.32723-1-jiangshanlai@gmail.com> <20220503150735.32723-4-jiangshanlai@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220503150735.32723-4-jiangshanlai@gmail.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, May 03, 2022 at 11:07:31PM +0800, Lai Jiangshan wrote: > From: Lai Jiangshan > > When special shadow pages are activated, link_shadow_page() might link > a special shadow pages which is the PAE root for PAE paging with its > children. > > Add make_pae_pdpte() to handle it. > > The code is not activated since special shadow pages are not activated > yet. > > Signed-off-by: Lai Jiangshan > --- > arch/x86/kvm/mmu/mmu.c | 6 +++++- > arch/x86/kvm/mmu/spte.c | 7 +++++++ > arch/x86/kvm/mmu/spte.h | 1 + > 3 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 126f0cd07f98..3fe70ad3bda2 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -2277,7 +2277,11 @@ static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, > > BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK); > > - spte = make_nonleaf_spte(sp->spt, sp_ad_disabled(sp)); > + if (unlikely(sp->role.level == PT32_ROOT_LEVEL && > + vcpu->arch.mmu->root_role.level == PT32E_ROOT_LEVEL)) > + spte = make_pae_pdpte(sp->spt); > + else > + spte = make_nonleaf_spte(sp->spt, sp_ad_disabled(sp)); > > mmu_spte_set(sptep, spte); > > diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c > index 75c9e87d446a..ccd9267a58ca 100644 > --- a/arch/x86/kvm/mmu/spte.c > +++ b/arch/x86/kvm/mmu/spte.c > @@ -251,6 +251,13 @@ u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) > return child_spte; > } > > +u64 make_pae_pdpte(u64 *child_pt) > +{ > + /* The only ignore bits in PDPTE are 11:9. */ > + BUILD_BUG_ON(!(GENMASK(11,9) & SPTE_MMU_PRESENT_MASK)); > + return __pa(child_pt) | PT_PRESENT_MASK | SPTE_MMU_PRESENT_MASK | > + shadow_me_value; If I'm reading mmu_alloc_{direct,shadow}_roots() correctly, PAE page directories just get: root | PT_PRESENT_MASK | shadow_me_value. Is there a reason to add SPTE_MMU_PRESENT_MASK or am I misreading the code? > +} > > u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled) > { > diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h > index fbbab180395e..09a7e4ba017a 100644 > --- a/arch/x86/kvm/mmu/spte.h > +++ b/arch/x86/kvm/mmu/spte.h > @@ -413,6 +413,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, > u64 old_spte, bool prefetch, bool can_unsync, > bool host_writable, u64 *new_spte); > u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index); > +u64 make_pae_pdpte(u64 *child_pt); > u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled); > u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access); > u64 mark_spte_for_access_track(u64 spte); > -- > 2.19.1.6.gb485710b >