Commit fd1369021878 ("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: Takuya Yoshikawa <yoshikawa_takuya_b1@xxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 7 ++++---
arch/x86/kvm/paging_tmpl.h | 2 +-
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index dd2a7c6..7d85bca 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -886,10 +886,11 @@ 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))
- *force_pt_level = !memslot_valid_for_gpte(slot, true);
+ 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;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index bf39d0f..b41faa9 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -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;
--
2.1.0
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