KVM: selftests: Add PTE helper for x86-64 in preparation for hugepages

Add a helper to retrieve a PTE pointer given a PFN, address, and level
in preparation for adding hugepage support.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622200529.3650424-17-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index fa4ad136b34d9b1443e879e62f44767ad9d03373..6796b65e181c6ef272e5fb26fd3ce32ce9375212 100644 (file)
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -216,10 +216,21 @@ void virt_pgd_alloc(struct kvm_vm *vm)
        }
 }
 
+static void *virt_get_pte(struct kvm_vm *vm, uint64_t pt_pfn, uint64_t vaddr,
+                         int level)
+{
+       uint64_t *page_table = addr_gpa2hva(vm, pt_pfn << vm->page_shift);
+       int index = vaddr >> (vm->page_shift + level * 9) & 0x1ffu;
+
+       return &page_table[index];
+}
+
 void virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
 {
-       uint16_t index[4];
        struct pageMapL4Entry *pml4e;
+       struct pageDirectoryPointerEntry *pdpe;
+       struct pageDirectoryEntry *pde;
+       struct pageTableEntry *pte;
 
        TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
                "unknown or unsupported guest mode, mode: 0x%x", vm->mode);
@@ -241,43 +252,35 @@ void virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
                "  paddr: 0x%lx vm->max_gfn: 0x%lx vm->page_size: 0x%x",
                paddr, vm->max_gfn, vm->page_size);
 
-       index[0] = (vaddr >> 12) & 0x1ffu;
-       index[1] = (vaddr >> 21) & 0x1ffu;
-       index[2] = (vaddr >> 30) & 0x1ffu;
-       index[3] = (vaddr >> 39) & 0x1ffu;
-
        /* Allocate page directory pointer table if not present. */
-       pml4e = addr_gpa2hva(vm, vm->pgd);
-       if (!pml4e[index[3]].present) {
-               pml4e[index[3]].pfn = vm_alloc_page_table(vm) >> vm->page_shift;
-               pml4e[index[3]].writable = true;
-               pml4e[index[3]].present = true;
+       pml4e = virt_get_pte(vm, vm->pgd >> vm->page_shift, vaddr, 3);
+       if (!pml4e->present) {
+               pml4e->pfn = vm_alloc_page_table(vm) >> vm->page_shift;
+               pml4e->writable = true;
+               pml4e->present = true;
        }
 
        /* Allocate page directory table if not present. */
-       struct pageDirectoryPointerEntry *pdpe;
-       pdpe = addr_gpa2hva(vm, pml4e[index[3]].pfn * vm->page_size);
-       if (!pdpe[index[2]].present) {
-               pdpe[index[2]].pfn = vm_alloc_page_table(vm) >> vm->page_shift;
-               pdpe[index[2]].writable = true;
-               pdpe[index[2]].present = true;
+       pdpe = virt_get_pte(vm, pml4e->pfn, vaddr, 2);
+       if (!pdpe->present) {
+               pdpe->pfn = vm_alloc_page_table(vm) >> vm->page_shift;
+               pdpe->writable = true;
+               pdpe->present = true;
        }
 
        /* Allocate page table if not present. */
-       struct pageDirectoryEntry *pde;
-       pde = addr_gpa2hva(vm, pdpe[index[2]].pfn * vm->page_size);
-       if (!pde[index[1]].present) {
-               pde[index[1]].pfn = vm_alloc_page_table(vm) >> vm->page_shift;
-               pde[index[1]].writable = true;
-               pde[index[1]].present = true;
+       pde = virt_get_pte(vm, pdpe->pfn, vaddr, 1);
+       if (!pde->present) {
+               pde->pfn = vm_alloc_page_table(vm) >> vm->page_shift;
+               pde->writable = true;
+               pde->present = true;
        }
 
        /* Fill in page table entry. */
-       struct pageTableEntry *pte;
-       pte = addr_gpa2hva(vm, pde[index[1]].pfn * vm->page_size);
-       pte[index[0]].pfn = paddr >> vm->page_shift;
-       pte[index[0]].writable = true;
-       pte[index[0]].present = 1;
+       pte = virt_get_pte(vm, pde->pfn, vaddr, 0);
+       pte->pfn = paddr >> vm->page_shift;
+       pte->writable = true;
+       pte->present = 1;
 }
 
 void virt_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent)