[RFC PATCH v3 09/16] KVM: arm64: Use separate function for the mapping size in user_mem_abort()

[Alexandru Elisei]

user_mem_abort() is already a long and complex function, let's make it
slightly easier to understand by abstracting the algorithm for choosing the
stage 2 IPA entry size into its own function.

This also makes it possible to reuse the code when guest SPE support will
be added.

Signed-off-by: Alexandru Elisei <alexandru.elisei at arm.com>
---
 arch/arm64/kvm/mmu.c | 55 ++++++++++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 19aacc7d64de..c3c43555490d 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -738,12 +738,43 @@ transparent_hugepage_adjust(struct kvm_memory_slot *memslot,
 	return PAGE_SIZE;
 }
 
+static short stage2_max_pageshift(struct kvm_memory_slot *memslot,
+				  struct vm_area_struct *vma, hva_t hva,
+				  bool *force_pte)
+{
+	short pageshift;
+
+	*force_pte = false;
+
+	if (is_vm_hugetlb_page(vma))
+		pageshift = huge_page_shift(hstate_vma(vma));
+	else
+		pageshift = PAGE_SHIFT;
+
+	if (memslot_is_logging(memslot) || (vma->vm_flags & VM_PFNMAP)) {
+		*force_pte = true;
+		pageshift = PAGE_SHIFT;
+	}
+
+	if (pageshift == PUD_SHIFT &&
+	    !fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
+		pageshift = PMD_SHIFT;
+
+	if (pageshift == PMD_SHIFT &&
+	    !fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) {
+		*force_pte = true;
+		pageshift = PAGE_SHIFT;
+	}
+
+	return pageshift;
+}
+
 static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 			  struct kvm_memory_slot *memslot, unsigned long hva,
 			  unsigned long fault_status)
 {
 	int ret = 0;
-	bool write_fault, writable, force_pte = false;
+	bool write_fault, writable, force_pte;
 	bool exec_fault;
 	bool device = false;
 	unsigned long mmu_seq;
@@ -776,27 +807,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		return -EFAULT;
 	}
 
-	if (is_vm_hugetlb_page(vma))
-		vma_shift = huge_page_shift(hstate_vma(vma));
-	else
-		vma_shift = PAGE_SHIFT;
-
-	if (logging_active ||
-	    (vma->vm_flags & VM_PFNMAP)) {
-		force_pte = true;
-		vma_shift = PAGE_SHIFT;
-	}
-
-	if (vma_shift == PUD_SHIFT &&
-	    !fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
-	       vma_shift = PMD_SHIFT;
-
-	if (vma_shift == PMD_SHIFT &&
-	    !fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) {
-		force_pte = true;
-		vma_shift = PAGE_SHIFT;
-	}
-
+	vma_shift = stage2_max_pageshift(memslot, vma, hva, &force_pte);
 	vma_pagesize = 1UL << vma_shift;
 	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
 		fault_ipa &= ~(vma_pagesize - 1);
-- 
2.29.1