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OpenCloudOS-Kernel
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KVM: x86/mmu: Move guest PT write-protection to account_shadowed() 

Move the code that write-protects newly-shadowed guest page tables into
account_shadowed(). This avoids a extra gfn-to-memslot lookup and is a
more logical place for this code to live. But most importantly, this
reduces kvm_mmu_alloc_shadow_page()'s reliance on having a struct
kvm_vcpu pointer, which will be necessary when creating new shadow pages
during VM ioctls for eager page splitting.

Note, it is safe to drop the role.level == PG_LEVEL_4K check since
account_shadowed() returns early if role.level > PG_LEVEL_4K.

No functional change intended.

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220516232138.1783324-10-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
David Matlack 2022-06-22 15:26:56 -04:00 committed by Paolo Bonzini
parent 876546436d
commit be91177133
1 changed files with 4 additions and 4 deletions
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8
arch/x86/kvm/mmu/mmu.c
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@ -766,6 +766,9 @@ static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
KVM_PAGE_TRACK_WRITE);
kvm_mmu_gfn_disallow_lpage(slot, gfn);
if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
kvm_flush_remote_tlbs_with_address(kvm, gfn, 1);
}
void account_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp)
@ -2072,11 +2075,8 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu,
sp->gfn = gfn;
sp->role = role;
hlist_add_head(&sp->hash_link, sp_list);
if (sp_has_gptes(sp)) {
if (sp_has_gptes(sp))
account_shadowed(vcpu->kvm, sp);
if (role.level == PG_LEVEL_4K && kvm_vcpu_write_protect_gfn(vcpu, gfn))
kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn, 1);
}
return sp;
}