KVM: selftests: Add wrapper to allocate page table page

Add a helper to allocate a page for use in constructing the guest's page
tables.  All architectures have identical address and memslot
requirements (which appear to be arbitrary anyways).

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622200529.3650424-15-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/include/kvm_util.h

@@ -30,6 +30,7 @@ typedef uint64_t vm_vaddr_t; /* Virtual Machine (Guest) virtual address */
 
 /* Minimum allocated guest virtual and physical addresses */
 #define KVM_UTIL_MIN_VADDR		0x2000
+#define KVM_GUEST_PAGE_TABLE_MIN_PADDR	0x180000
 
 #define DEFAULT_GUEST_PHY_PAGES		512
 #define DEFAULT_GUEST_STACK_VADDR_MIN	0xab6000
@@ -262,6 +263,7 @@ vm_paddr_t vm_phy_page_alloc(struct kvm_vm *vm, vm_paddr_t paddr_min,
 			     uint32_t memslot);
 vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
 			      vm_paddr_t paddr_min, uint32_t memslot);
+vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
 
 /*
  * Create a VM with reasonable defaults

tools/testing/selftests/kvm/lib/aarch64/processor.c

@@ -11,7 +11,6 @@
 #include "../kvm_util_internal.h"
 #include "processor.h"
 
-#define KVM_GUEST_PAGE_TABLE_MIN_PADDR		0x180000
 #define DEFAULT_ARM64_GUEST_STACK_VADDR_MIN	0xac0000
 
 static uint64_t page_align(struct kvm_vm *vm, uint64_t v)
@@ -104,25 +103,19 @@ static void _virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
 		paddr, vm->max_gfn, vm->page_size);
 
 	ptep = addr_gpa2hva(vm, vm->pgd) + pgd_index(vm, vaddr) * 8;
-	if (!*ptep) {
-		*ptep = vm_phy_page_alloc(vm, KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
-		*ptep |= 3;
-	}
+	if (!*ptep)
+		*ptep = vm_alloc_page_table(vm) | 3;
 
 	switch (vm->pgtable_levels) {
 	case 4:
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pud_index(vm, vaddr) * 8;
-		if (!*ptep) {
-			*ptep = vm_phy_page_alloc(vm, KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
-			*ptep |= 3;
-		}
+		if (!*ptep)
+			*ptep = vm_alloc_page_table(vm) | 3;
 		/* fall through */
 	case 3:
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pmd_index(vm, vaddr) * 8;
-		if (!*ptep) {
-			*ptep = vm_phy_page_alloc(vm, KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
-			*ptep |= 3;
-		}
+		if (!*ptep)
+			*ptep = vm_alloc_page_table(vm) | 3;
 		/* fall through */
 	case 2:
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pte_index(vm, vaddr) * 8;

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -2209,6 +2209,14 @@ vm_paddr_t vm_phy_page_alloc(struct kvm_vm *vm, vm_paddr_t paddr_min,
 	return vm_phy_pages_alloc(vm, 1, paddr_min, memslot);
 }
 
+/* Arbitrary minimum physical address used for virtual translation tables. */
+#define KVM_GUEST_PAGE_TABLE_MIN_PADDR 0x180000
+
+vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm)
+{
+	return vm_phy_page_alloc(vm, KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
+}
+
 /*
  * Address Guest Virtual to Host Virtual
  *

tools/testing/selftests/kvm/lib/s390x/processor.c

@@ -9,8 +9,6 @@
 #include "kvm_util.h"
 #include "../kvm_util_internal.h"
 
-#define KVM_GUEST_PAGE_TABLE_MIN_PADDR		0x180000
-
 #define PAGES_PER_REGION 4
 
 void virt_pgd_alloc(struct kvm_vm *vm)

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

@@ -17,9 +17,6 @@
 #define DEFAULT_CODE_SELECTOR 0x8
 #define DEFAULT_DATA_SELECTOR 0x10
 
-/* Minimum physical address used for virtual translation tables. */
-#define KVM_GUEST_PAGE_TABLE_MIN_PADDR 0x180000
-
 vm_vaddr_t exception_handlers;
 
 /* Virtual translation table structure declarations */
@@ -214,9 +211,7 @@ void virt_pgd_alloc(struct kvm_vm *vm)
 
 	/* If needed, create page map l4 table. */
 	if (!vm->pgd_created) {
-		vm_paddr_t paddr = vm_phy_page_alloc(vm,
-			KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
-		vm->pgd = paddr;
+		vm->pgd = vm_alloc_page_table(vm);
 		vm->pgd_created = true;
 	}
 }
@@ -254,9 +249,7 @@ void virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
 	/* Allocate page directory pointer table if not present. */
 	pml4e = addr_gpa2hva(vm, vm->pgd);
 	if (!pml4e[index[3]].present) {
-		pml4e[index[3]].address = vm_phy_page_alloc(vm,
-			KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0)
-			>> vm->page_shift;
+		pml4e[index[3]].address = vm_alloc_page_table(vm) >> vm->page_shift;
 		pml4e[index[3]].writable = true;
 		pml4e[index[3]].present = true;
 	}
@@ -265,9 +258,7 @@ void virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
 	struct pageDirectoryPointerEntry *pdpe;
 	pdpe = addr_gpa2hva(vm, pml4e[index[3]].address * vm->page_size);
 	if (!pdpe[index[2]].present) {
-		pdpe[index[2]].address = vm_phy_page_alloc(vm,
-			KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0)
-			>> vm->page_shift;
+		pdpe[index[2]].address = vm_alloc_page_table(vm) >> vm->page_shift;
 		pdpe[index[2]].writable = true;
 		pdpe[index[2]].present = true;
 	}
@@ -276,9 +267,7 @@ void virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
 	struct pageDirectoryEntry *pde;
 	pde = addr_gpa2hva(vm, pdpe[index[2]].address * vm->page_size);
 	if (!pde[index[1]].present) {
-		pde[index[1]].address = vm_phy_page_alloc(vm,
-			KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0)
-			>> vm->page_shift;
+		pde[index[1]].address = vm_alloc_page_table(vm) >> vm->page_shift;
 		pde[index[1]].writable = true;
 		pde[index[1]].present = true;
 	}

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

@@ -426,9 +426,7 @@ void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
 	/* Allocate page directory pointer table if not present. */
 	pml4e = vmx->eptp_hva;
 	if (!pml4e[index[3]].readable) {
-		pml4e[index[3]].address = vm_phy_page_alloc(vm,
-			  KVM_EPT_PAGE_TABLE_MIN_PADDR, 0)
-			>> vm->page_shift;
+		pml4e[index[3]].address = vm_alloc_page_table(vm) >> vm->page_shift;
 		pml4e[index[3]].writable = true;
 		pml4e[index[3]].readable = true;
 		pml4e[index[3]].executable = true;
@@ -438,9 +436,7 @@ void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
 	struct eptPageTableEntry *pdpe;
 	pdpe = addr_gpa2hva(vm, pml4e[index[3]].address * vm->page_size);
 	if (!pdpe[index[2]].readable) {
-		pdpe[index[2]].address = vm_phy_page_alloc(vm,
-			  KVM_EPT_PAGE_TABLE_MIN_PADDR, 0)
-			>> vm->page_shift;
+		pdpe[index[2]].address = vm_alloc_page_table(vm) >> vm->page_shift;
 		pdpe[index[2]].writable = true;
 		pdpe[index[2]].readable = true;
 		pdpe[index[2]].executable = true;
@@ -450,9 +446,7 @@ void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
 	struct eptPageTableEntry *pde;
 	pde = addr_gpa2hva(vm, pdpe[index[2]].address * vm->page_size);
 	if (!pde[index[1]].readable) {
-		pde[index[1]].address = vm_phy_page_alloc(vm,
-			  KVM_EPT_PAGE_TABLE_MIN_PADDR, 0)
-			>> vm->page_shift;
+		pde[index[1]].address = vm_alloc_page_table(vm) >> vm->page_shift;
 		pde[index[1]].writable = true;
 		pde[index[1]].readable = true;
 		pde[index[1]].executable = true;