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Subject[PATCH 11/16] KVM: x86/mmu: Consolidate tdp_page_fault() and nonpaging_page_fault()
Date
Consolidate the direct MMU page fault handlers into a common helper,
direct_page_fault(). Except for unique max level conditions, the tdp
and nonpaging fault handlers are functionally identical.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 166 +++++++++++++++--------------------------
1 file changed, 61 insertions(+), 105 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a09a3bc0b6ae..929fca02b075 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4169,67 +4169,72 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
return false;
}

-static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa,
- u32 error_code, bool prefault)
+static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
+ bool prefault, int max_level, bool is_tdp)
{
- int r;
- int level;
- kvm_pfn_t pfn;
- unsigned long mmu_seq;
- gfn_t gfn = gpa >> PAGE_SHIFT;
bool write = error_code & PFERR_WRITE_MASK;
- bool map_writable;
bool exec = error_code & PFERR_FETCH_MASK;
bool lpage_disallowed = exec && is_nx_huge_page_enabled();
- int max_level;
+ bool map_writable;

- /* Note, paging is disabled, ergo gva == gpa. */
+ gfn_t gfn = gpa >> PAGE_SHIFT;
+ unsigned long mmu_seq;
+ kvm_pfn_t pfn;
+ int level, r;
+
+ MMU_WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa));
+
+ if (page_fault_handle_page_track(vcpu, error_code, gfn))
+ return RET_PF_EMULATE;
+
+ r = mmu_topup_memory_caches(vcpu);
+ if (r)
+ return r;
+
+ if (lpage_disallowed)
+ max_level = PT_PAGE_TABLE_LEVEL;
+
+ level = mapping_level(vcpu, gfn, &max_level);
+ if (level > PT_PAGE_TABLE_LEVEL)
+ gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
+
+ if (fast_page_fault(vcpu, gpa, level, error_code))
+ return RET_PF_RETRY;
+
+ mmu_seq = vcpu->kvm->mmu_notifier_seq;
+ smp_rmb();
+
+ if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
+ return RET_PF_RETRY;
+
+ if (handle_abnormal_pfn(vcpu, is_tdp ? 0 : gpa, gfn, pfn, ACC_ALL, &r))
+ return r;
+
+ r = RET_PF_RETRY;
+ spin_lock(&vcpu->kvm->mmu_lock);
+ if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
+ goto out_unlock;
+ if (make_mmu_pages_available(vcpu) < 0)
+ goto out_unlock;
+ if (likely(max_level > PT_PAGE_TABLE_LEVEL))
+ transparent_hugepage_adjust(vcpu, gfn, &pfn, &level);
+ r = __direct_map(vcpu, gpa, write, map_writable, level, pfn, prefault,
+ is_tdp && lpage_disallowed);
+
+out_unlock:
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ kvm_release_pfn_clean(pfn);
+ return r;
+}
+
+static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa,
+ u32 error_code, bool prefault)
+{
pgprintk("%s: gva %lx error %x\n", __func__, gpa, error_code);

- gpa &= PAGE_MASK;
-
- if (page_fault_handle_page_track(vcpu, error_code, gfn))
- return RET_PF_EMULATE;
-
- r = mmu_topup_memory_caches(vcpu);
- if (r)
- return r;
-
- MMU_WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa));
-
/* This path builds a PAE pagetable, we can map 2mb pages at maximum. */
- max_level = lpage_disallowed ? PT_PAGE_TABLE_LEVEL : PT_DIRECTORY_LEVEL;
-
- level = mapping_level(vcpu, gfn, &max_level);
- if (level > PT_PAGE_TABLE_LEVEL)
- gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
-
- if (fast_page_fault(vcpu, gpa, level, error_code))
- return RET_PF_RETRY;
-
- mmu_seq = vcpu->kvm->mmu_notifier_seq;
- smp_rmb();
-
- if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
- return RET_PF_RETRY;
-
- if (handle_abnormal_pfn(vcpu, gpa, gfn, pfn, ACC_ALL, &r))
- return r;
-
- r = RET_PF_RETRY;
- spin_lock(&vcpu->kvm->mmu_lock);
- if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
- goto out_unlock;
- if (make_mmu_pages_available(vcpu) < 0)
- goto out_unlock;
- if (likely(max_level > PT_PAGE_TABLE_LEVEL))
- transparent_hugepage_adjust(vcpu, gfn, &pfn, &level);
- r = __direct_map(vcpu, gpa, write, map_writable, level, pfn,
- prefault, false);
-out_unlock:
- spin_unlock(&vcpu->kvm->mmu_lock);
- kvm_release_pfn_clean(pfn);
- return r;
+ return direct_page_fault(vcpu, gpa & PAGE_MASK, error_code, prefault,
+ PT_DIRECTORY_LEVEL, false);
}

int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
@@ -4273,69 +4278,20 @@ EXPORT_SYMBOL_GPL(kvm_handle_page_fault);
static int tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
bool prefault)
{
- kvm_pfn_t pfn;
- int r;
- int level;
- gfn_t gfn = gpa >> PAGE_SHIFT;
- unsigned long mmu_seq;
- int write = error_code & PFERR_WRITE_MASK;
- 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));
-
- if (page_fault_handle_page_track(vcpu, error_code, gfn))
- return RET_PF_EMULATE;
-
- r = mmu_topup_memory_caches(vcpu);
- if (r)
- return r;
-
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);
+ gfn_t base = (gpa >> PAGE_SHIFT) & ~(page_num - 1);

if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num))
break;
}

- if (lpage_disallowed)
- max_level = PT_PAGE_TABLE_LEVEL;
-
- level = mapping_level(vcpu, gfn, &max_level);
- if (level > PT_PAGE_TABLE_LEVEL)
- gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
-
- if (fast_page_fault(vcpu, gpa, level, error_code))
- return RET_PF_RETRY;
-
- mmu_seq = vcpu->kvm->mmu_notifier_seq;
- smp_rmb();
-
- if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
- return RET_PF_RETRY;
-
- if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
- return r;
-
- r = RET_PF_RETRY;
- spin_lock(&vcpu->kvm->mmu_lock);
- if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
- goto out_unlock;
- if (make_mmu_pages_available(vcpu) < 0)
- goto out_unlock;
- if (likely(max_level > PT_PAGE_TABLE_LEVEL))
- transparent_hugepage_adjust(vcpu, gfn, &pfn, &level);
- r = __direct_map(vcpu, gpa, write, map_writable, level, pfn,
- prefault, lpage_disallowed);
-out_unlock:
- spin_unlock(&vcpu->kvm->mmu_lock);
- kvm_release_pfn_clean(pfn);
- return r;
+ return direct_page_fault(vcpu, gpa, error_code, prefault,
+ max_level, true);
}

static void nonpaging_init_context(struct kvm_vcpu *vcpu,
--
2.24.0
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