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Commit 8c85ac1c authored by Takuya Yoshikawa's avatar Takuya Yoshikawa Committed by Paolo Bonzini
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KVM: x86: MMU: Initialize force_pt_level before calling mapping_level() 



Commit fd136902 ("KVM: x86: MMU: Move mapping_level_dirty_bitmap()
call in mapping_level()") forgot to initialize force_pt_level to false
in FNAME(page_fault)() before calling mapping_level() like
nonpaging_map() does.  This can sometimes result in forcing page table
level mapping unnecessarily.

Fix this and move the first *force_pt_level check in mapping_level()
before kvm_vcpu_gfn_to_memslot() call to make it a bit clearer that
the variable must be initialized before mapping_level() gets called.

This change can also avoid calling kvm_vcpu_gfn_to_memslot() when
!check_hugepage_cache_consistency() check in tdp_page_fault() forces
page table level mapping.

Signed-off-by: default avatarTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 5690891b

arch/x86/kvm/mmu.c

+4 −3
Original line number Diff line number Diff line
@@ -886,9 +886,10 @@ static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn, 
	int host_level, level, max_level;

	struct kvm_memory_slot *slot;



	slot = kvm_vcpu_gfn_to_memslot(vcpu, large_gfn);

	if (unlikely(*force_pt_level))

		return PT_PAGE_TABLE_LEVEL;



	if (likely(!*force_pt_level))

	slot = kvm_vcpu_gfn_to_memslot(vcpu, large_gfn);

	*force_pt_level = !memslot_valid_for_gpte(slot, true);

	if (unlikely(*force_pt_level))

		return PT_PAGE_TABLE_LEVEL;

arch/x86/kvm/paging_tmpl.h

+1 −1
Original line number Diff line number Diff line
@@ -698,7 +698,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code, 
	int r;

	pfn_t pfn;

	int level = PT_PAGE_TABLE_LEVEL;

	bool force_pt_level;

	bool force_pt_level = false;

	unsigned long mmu_seq;

	bool map_writable, is_self_change_mapping;