[Intel-gfx] [PATCH 02/27] KVM: x86/mmu: Factor out helper to get max mapping size of a memslot

[Sean Christopherson]

Extract the memslot-related logic of kvm_mmu_max_mapping_level() into a
new helper so that KVMGT can determine whether or not mapping a 2MiB page
into the guest is (dis)allowed per KVM's memslots.

No functional change intended.

Signed-off-by: Sean Christopherson <sea...@google.com>
---
 arch/x86/kvm/mmu/mmu.c          | 21 +++++++++++++++------
 arch/x86/kvm/mmu/mmu_internal.h |  2 ++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 254bc46234e0..ca7428b68eba 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3064,20 +3064,29 @@ static int host_pfn_mapping_level(struct kvm *kvm, 
gfn_t gfn,
        return level;
 }
 
+int kvm_mmu_max_slot_mapping_level(const struct kvm_memory_slot *slot,
+                                  gfn_t gfn, int max_level)
+{
+       struct kvm_lpage_info *linfo;
+
+       for ( ; max_level > PG_LEVEL_4K; max_level--) {
+               linfo = lpage_info_slot(gfn, slot, max_level);
+               if (!linfo->disallow_lpage)
+                       break;
+       }
+       return max_level;
+}
+
 int kvm_mmu_max_mapping_level(struct kvm *kvm,
                              const struct kvm_memory_slot *slot, gfn_t gfn,
                              int max_level)
 {
-       struct kvm_lpage_info *linfo;
        int host_level;
 
        max_level = min(max_level, max_huge_page_level);
-       for ( ; max_level > PG_LEVEL_4K; max_level--) {
-               linfo = lpage_info_slot(gfn, slot, max_level);
-               if (!linfo->disallow_lpage)
-                       break;
-       }
+       max_level = kvm_mmu_max_slot_mapping_level(slot, gfn, max_level);
 
+       /* Avoid walking the host page tables if a hugepage is impossible. */
        if (max_level == PG_LEVEL_4K)
                return PG_LEVEL_4K;
 
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index ac00bfbf32f6..b078c29e5674 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -314,6 +314,8 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu 
*vcpu, gpa_t cr2_or_gpa,
        return r;
 }
 
+int kvm_mmu_max_slot_mapping_level(const struct kvm_memory_slot *slot,
+                                  gfn_t gfn, int max_level);
 int kvm_mmu_max_mapping_level(struct kvm *kvm,
                              const struct kvm_memory_slot *slot, gfn_t gfn,
                              int max_level);
-- 
2.39.0.314.g84b9a713c41-goog