KVM: selftests: Drop helpers to read/write page table entries

Drop vm_{g,s}et_page_table_entry() and instead expose the "inner"
helper (was _vm_get_page_table_entry()) that returns a _pointer_ to the
PTE, i.e. let tests directly modify PTEs instead of bouncing through
helpers that just make life difficult.

Opportunsitically use BIT_ULL() in emulator_error_test, and use the
MAXPHYADDR define to set the "rogue" GPA bit instead of open coding the
same value.

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-2-seanjc@google.com

tools/testing/selftests/kvm/include/x86_64/processor.h

@@ -827,10 +827,8 @@ static inline uint8_t wrmsr_safe(uint32_t msr, uint64_t val)
 
 bool kvm_is_tdp_enabled(void);
 
-uint64_t vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
-				 uint64_t vaddr);
-void vm_set_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
-			     uint64_t vaddr, uint64_t pte);
+uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
+				  uint64_t vaddr);
 
 uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2,
 		       uint64_t a3);

tools/testing/selftests/kvm/lib/x86_64/processor.c

@@ -241,9 +241,8 @@ void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
 	}
 }
 
-static uint64_t *_vm_get_page_table_entry(struct kvm_vm *vm,
-					  struct kvm_vcpu *vcpu,
-					  uint64_t vaddr)
+uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
+				  uint64_t vaddr)
 {
 	uint16_t index[4];
 	uint64_t *pml4e, *pdpe, *pde;
@@ -313,22 +312,6 @@ static uint64_t *_vm_get_page_table_entry(struct kvm_vm *vm,
 	return &pte[index[0]];
 }
 
-uint64_t vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
-				 uint64_t vaddr)
-{
-	uint64_t *pte = _vm_get_page_table_entry(vm, vcpu, vaddr);
-
-	return *(uint64_t *)pte;
-}
-
-void vm_set_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
-			     uint64_t vaddr, uint64_t pte)
-{
-	uint64_t *new_pte = _vm_get_page_table_entry(vm, vcpu, vaddr);
-
-	*(uint64_t *)new_pte = pte;
-}
-
 void virt_arch_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent)
 {
 	uint64_t *pml4e, *pml4e_start;

tools/testing/selftests/kvm/x86_64/emulator_error_test.c

@@ -152,8 +152,9 @@ int main(int argc, char *argv[])
 {
 	struct kvm_vcpu *vcpu;
 	struct kvm_vm *vm;
-	uint64_t gpa, pte;
+	uint64_t *pte;
 	uint64_t *hva;
+	uint64_t gpa;
 	int rc;
 
 	/* Tell stdout not to buffer its content */
@@ -178,8 +179,9 @@ int main(int argc, char *argv[])
 	virt_map(vm, MEM_REGION_GVA, MEM_REGION_GPA, 1);
 	hva = addr_gpa2hva(vm, MEM_REGION_GPA);
 	memset(hva, 0, PAGE_SIZE);
+
 	pte = vm_get_page_table_entry(vm, vcpu, MEM_REGION_GVA);
-	vm_set_page_table_entry(vm, vcpu, MEM_REGION_GVA, pte | (1ull << 36));
+	*pte |= BIT_ULL(MAXPHYADDR);
 
 	vcpu_run(vcpu);
 	process_exit_on_emulation_error(vcpu);