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Date: Sat, 21 May 2022 21:16:59 +0800 From: Lai Jiangshan <jiangshanlai@...il.com> To: linux-kernel@...r.kernel.org, kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com> Cc: Vitaly Kuznetsov <vkuznets@...hat.com>, Maxim Levitsky <mlevitsk@...hat.com>, David Matlack <dmatlack@...gle.com>, Lai Jiangshan <jiangshan.ljs@...group.com> Subject: [PATCH V3 11/12] KVM: X86/MMU: Don't use mmu->pae_root when shadowing PAE NPT in 64-bit host From: Lai Jiangshan <jiangshan.ljs@...group.com> Allocate the tables when allocating the local shadow page. Signed-off-by: Lai Jiangshan <jiangshan.ljs@...group.com> --- arch/x86/kvm/mmu/mmu.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 63c2b2c6122c..73e6a8e1e1a9 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1809,10 +1809,12 @@ static bool using_local_root_page(struct kvm_mmu *mmu) * 2 or 3 levels of local shadow pages on top of non-local shadow pages. * * Local shadow pages are locally allocated. If the local shadow page's level - * is PT32E_ROOT_LEVEL, it will use the preallocated mmu->pae_root for its - * sp->spt. Because sp->spt may need to be put in the 32 bits CR3 (even in - * x86_64) or decrypted. Using the preallocated one to handle these - * requirements makes the allocation simpler. + * is PT32E_ROOT_LEVEL, and it is not shadowing nested NPT for 32-bit L1 in + * 64-bit L0 (or said when the shadow pagetable's level is PT32E_ROOT_LEVEL), + * it will use the preallocated mmu->pae_root for its sp->spt. Because sp->spt + * need to be put in the 32-bit CR3 (even in 64-bit host) or decrypted. Using + * the preallocated one to handle these requirements makes the allocation + * simpler. * * Local shadow pages are only visible to local VCPU except through * sp->parent_ptes rmap from their children, so they are not in the @@ -1852,13 +1854,12 @@ kvm_mmu_alloc_local_shadow_page(struct kvm_vcpu *vcpu, union kvm_mmu_page_role r sp->gfn = 0; sp->role = role; /* - * Use the preallocated mmu->pae_root when the shadow page's - * level is PT32E_ROOT_LEVEL which may need to be put in the 32 bits + * Use the preallocated mmu->pae_root when the shadow pagetable's + * level is PT32E_ROOT_LEVEL which need to be put in the 32 bits * CR3 (even in x86_64) or decrypted. The preallocated one is prepared * for the requirements. */ - if (role.level == PT32E_ROOT_LEVEL && - !WARN_ON_ONCE(!vcpu->arch.mmu->pae_root)) + if (vcpu->arch.mmu->root_role.level == PT32E_ROOT_LEVEL) sp->spt = vcpu->arch.mmu->pae_root; else sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); -- 2.19.1.6.gb485710b
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