[RFC v3 02/10] KVM: selftests: Add aligned guest physical page allocator

[Ritesh Harjani (IBM)]

From: Nicholas Piggin <npiggin@xxxxxxxxx>

powerpc will require this to allocate MMU tables in guest memory that
are larger than guest base page size.

Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
[Rebased to latest mainline tree]
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
---
 .../testing/selftests/kvm/include/kvm_util.h  | 20 +++++++++--
 tools/testing/selftests/kvm/lib/kvm_util.c    | 33 +++++++++----------
 2 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 3666a8530f31..c515c918c2c9 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -991,8 +991,8 @@ void kvm_gsi_routing_write(struct kvm_vm *vm, struct kvm_irq_routing *routing);
 const char *exit_reason_str(unsigned int exit_reason);
 
 gpa_t vm_phy_page_alloc(struct kvm_vm *vm, gpa_t min_gpa, u32 memslot);
-gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, gpa_t min_gpa,
-			   u32 memslot, bool protected);
+gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, size_t align,
+			   gpa_t min_gpa, u32 memslot, bool protected);
 gpa_t vm_alloc_page_table(struct kvm_vm *vm);
 
 static inline gpa_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
@@ -1003,10 +1003,24 @@ static inline gpa_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
 	 * protected memory, as the majority of memory for such VMs is
 	 * protected, i.e. using shared memory is effectively opt-in.
 	 */
-	return __vm_phy_pages_alloc(vm, num, min_gpa, memslot,
+	return __vm_phy_pages_alloc(vm, num, 1, min_gpa, memslot,
 				    vm_arch_has_protected_memory(vm));
 }
 
+static inline gpa_t vm_phy_pages_alloc_align(struct kvm_vm *vm, size_t num,
+					     size_t align, gpa_t min_gpa,
+					     u32 memslot)
+{
+	/*
+	 * By default, allocate memory as protected for VMs that support
+	 * protected memory, as the majority of memory for such VMs is
+	 * protected, i.e. using shared memory is effectively opt-in.
+	 */
+	return __vm_phy_pages_alloc(vm, num, align, min_gpa, memslot,
+				    vm_arch_has_protected_memory(vm));
+}
+
+
 /*
  * ____vm_create() does KVM_CREATE_VM and little else.  __vm_create() also
  * loads the test binary into guest memory and creates an IRQ chip (x86 only).
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index e08967ef7b7b..ac7215824203 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1442,7 +1442,7 @@ static gva_t ____vm_alloc(struct kvm_vm *vm, size_t sz, gva_t min_gva,
 	u64 pages = (sz >> vm->page_shift) + ((sz % vm->page_size) != 0);
 
 	virt_pgd_alloc(vm);
-	gpa_t gpa = __vm_phy_pages_alloc(vm, pages,
+	gpa_t gpa = __vm_phy_pages_alloc(vm, pages, 1,
 					   KVM_UTIL_MIN_PFN * vm->page_size,
 					   vm->memslots[type], protected);
 
@@ -2021,7 +2021,7 @@ const char *exit_reason_str(unsigned int exit_reason)
  * and their base address is returned. A TEST_ASSERT failure occurs if
  * not enough pages are available at or above min_gpa.
  */
-gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
+gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, size_t align,
 			   gpa_t min_gpa, u32 memslot,
 			   bool protected)
 {
@@ -2039,23 +2039,22 @@ gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
 	TEST_ASSERT(!protected || region->protected_phy_pages,
 		    "Region doesn't support protected memory");
 
-	base = pg = min_gpa >> vm->page_shift;
-	do {
-		for (; pg < base + num; ++pg) {
-			if (!sparsebit_is_set(region->unused_phy_pages, pg)) {
-				base = pg = sparsebit_next_set(region->unused_phy_pages, pg);
-				break;
+	base = min_gpa >> vm->page_shift;
+again:
+	base = (base + align - 1) & ~(align - 1);
+	for (pg = base; pg < base + num; ++pg) {
+		if (!sparsebit_is_set(region->unused_phy_pages, pg)) {
+			base = sparsebit_next_set(region->unused_phy_pages, pg);
+			if (!base) {
+				fprintf(stderr, "No guest physical page available, "
+					"min_gpa: 0x%lx page_size: 0x%x memslot: %u\n",
+					min_gpa, vm->page_size, memslot);
+				fputs("---- vm dump ----\n", stderr);
+				vm_dump(stderr, vm, 2);
+				abort();
 			}
+			goto again;
 		}
-	} while (pg && pg != base + num);
-
-	if (pg == 0) {
-		fprintf(stderr, "No guest physical page available, "
-			"min_gpa: 0x%lx page_size: 0x%x memslot: %u\n",
-			min_gpa, vm->page_size, memslot);
-		fputs("---- vm dump ----\n", stderr);
-		vm_dump(stderr, vm, 2);
-		abort();
 	}
 
 	for (pg = base; pg < base + num; ++pg) {
-- 
2.39.5