From: Lai Jiangshan <jiangshanlai@gmail.com>
To: David Matlack <dmatlack@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
"open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)"
<kvm@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Lai Jiangshan <jiangshan.ljs@antgroup.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH V2 3/7] KVM: X86/MMU: Link PAE root pagetable with its children
Date: Tue, 17 May 2022 09:13:54 +0800 [thread overview]
Message-ID: <CAJhGHyCKdxti0gDjDP27MDd=bK+0BecXqzExo5t-WAOQLO5WwA@mail.gmail.com> (raw)
In-Reply-To: <YoLlzcejEDh8VpoB@google.com>
On Tue, May 17, 2022 at 8:01 AM David Matlack <dmatlack@google.com> wrote:
>
> On Tue, May 03, 2022 at 11:07:31PM +0800, Lai Jiangshan wrote:
> > From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
> >
> > 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 <jiangshan.ljs@antgroup.com>
> > ---
> > 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?
Because it has a struct kvm_mmu_page associated with it now.
sp->spt[i] requires SPTE_MMU_PRESENT_MASK if it is present.
>
> > +}
> >
> > 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
> >
next prev parent reply other threads:[~2022-05-17 1:14 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-03 15:07 [PATCH V2 0/7] KVM: X86/MMU: Use one-off special shadow page for special roots Lai Jiangshan
2022-05-03 15:07 ` [PATCH V2 1/7] KVM: X86/MMU: Add using_special_root_page() Lai Jiangshan
2022-05-13 22:53 ` David Matlack
2022-05-26 9:20 ` Lai Jiangshan
2022-05-03 15:07 ` [PATCH V2 2/7] KVM: X86/MMU: Add special shadow pages Lai Jiangshan
2022-05-13 23:43 ` David Matlack
2022-05-26 9:38 ` Lai Jiangshan
2022-05-03 15:07 ` [PATCH V2 3/7] KVM: X86/MMU: Link PAE root pagetable with its children Lai Jiangshan
2022-05-17 0:01 ` David Matlack
2022-05-17 1:13 ` Lai Jiangshan [this message]
2022-05-17 16:41 ` David Matlack
2022-05-26 9:12 ` Lai Jiangshan
2022-05-03 15:07 ` [PATCH V2 4/7] KVM: X86/MMU: Activate special shadow pages and remove old logic Lai Jiangshan
2022-05-17 0:16 ` David Matlack
2022-05-26 9:15 ` Lai Jiangshan
2022-05-03 15:07 ` [PATCH V2 5/7] KVM: X86/MMU: Remove the check of the return value of to_shadow_page() Lai Jiangshan
2022-05-17 16:47 ` David Matlack
2022-05-03 15:07 ` [PATCH V2 6/7] KVM: X86/MMU: Allocate mmu->pae_root for PAE paging on-demand Lai Jiangshan
2022-05-17 16:57 ` David Matlack
2022-05-26 8:52 ` Lai Jiangshan
2022-05-03 15:07 ` [PATCH V2 7/7] KVM: X86/MMU: Remove mmu_alloc_special_roots() Lai Jiangshan
2022-05-13 8:22 ` [PATCH V2 0/7] KVM: X86/MMU: Use one-off special shadow page for special roots Lai Jiangshan
2022-05-13 18:31 ` David Matlack
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