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Subject[PATCH 05/16] KVM: x86/mmu: Refactor handling of cache consistency with TDP
Date
Pre-calculate the max level for a TDP page with respect to MTRR cache
consistency in preparation of replacing force_pt_level with max_level,
and eventually combining the bulk of nonpaging_page_fault() and
tdp_page_fault() into a common helper.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ef1b7663f6ea..e4a96236aa14 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4267,16 +4267,6 @@ int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
}
EXPORT_SYMBOL_GPL(kvm_handle_page_fault);

-static bool
-check_hugepage_cache_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, int level)
-{
- int page_num = KVM_PAGES_PER_HPAGE(level);
-
- gfn &= ~(page_num - 1);
-
- return kvm_mtrr_check_gfn_range_consistency(vcpu, gfn, page_num);
-}
-
static int tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
bool prefault)
{
@@ -4290,6 +4280,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
bool map_writable;
bool lpage_disallowed = (error_code & PFERR_FETCH_MASK) &&
is_nx_huge_page_enabled();
+ int max_level;

MMU_WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa));

@@ -4300,14 +4291,21 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
if (r)
return r;

- force_pt_level =
- lpage_disallowed ||
- !check_hugepage_cache_consistency(vcpu, gfn, PT_DIRECTORY_LEVEL);
+ for (max_level = PT_MAX_HUGEPAGE_LEVEL;
+ max_level > PT_PAGE_TABLE_LEVEL;
+ max_level--) {
+ int page_num = KVM_PAGES_PER_HPAGE(max_level);
+ gfn_t base = gfn & ~(page_num - 1);
+
+ if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num))
+ break;
+ }
+
+ force_pt_level = lpage_disallowed || max_level == PT_PAGE_TABLE_LEVEL;
level = mapping_level(vcpu, gfn, &force_pt_level);
if (likely(!force_pt_level)) {
- if (level > PT_DIRECTORY_LEVEL &&
- !check_hugepage_cache_consistency(vcpu, gfn, level))
- level = PT_DIRECTORY_LEVEL;
+ if (level > max_level)
+ level = max_level;
gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
}

--
2.24.0
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