[PATCH 06/20] KVM: selftests: Extend page allocator to support naturally aligned allocations

Extend the page allocator to support naturally aligned allocations, as some
flavors of PowerPC page tables require multiple guest pages per table, and
those tables need to be naturally aligned.

Take care to align the potential base address *inside* the retry loop, i.e.
the base needs to be (re)aligned on every attempt.

Signed-off-by: Sean Christopherson <[email protected]>
---
 tools/testing/selftests/kvm/include/kvm_util.h |  2 ++
 tools/testing/selftests/kvm/lib/kvm_util.c     | 13 +++++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index b1c5597b1def..96c8251c224a 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -991,6 +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 nr_pages, gpa_t min_gpa,
+			     u32 memslot, bool protected, bool naturally_aligned);
 gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
 			   u32 memslot, bool protected);
 gpa_t vm_alloc_page_table(struct kvm_vm *vm);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index bbf6d7684c0c..896da440659e 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 #include <unistd.h>
+#include <linux/align.h>
 #include <linux/kernel.h>
 
 #define KVM_UTIL_MIN_PFN	2
@@ -2032,9 +2033,10 @@ const char *exit_reason_str(unsigned int exit_reason)
  *
  * Note, success is guaranteed!
  */
-gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
-			   u32 memslot, bool protected)
+gpa_t ____vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
+			     u32 memslot, bool protected, bool naturally_aligned)
 {
+	size_t alignment = naturally_aligned ? nr_pages : 1;
 	struct userspace_mem_region *region;
 	sparsebit_idx_t pg, base;
 
@@ -2051,6 +2053,7 @@ gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
 
 	base = min_gpa >> vm->page_shift;
 again:
+	base = ALIGN(base, alignment);
 	for (pg = base; pg < base + nr_pages; ++pg) {
 		if (!sparsebit_is_set(region->unused_phy_pages, pg)) {
 			base = sparsebit_next_set(region->unused_phy_pages, pg);
@@ -2077,6 +2080,12 @@ gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
 	__builtin_unreachable();
 }
 
+gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
+			   u32 memslot, bool protected)
+{
+	return ____vm_phy_pages_alloc(vm, nr_pages, min_gpa, memslot, protected, false);
+}
+
 gpa_t vm_phy_page_alloc(struct kvm_vm *vm, gpa_t min_gpa, u32 memslot)
 {
 	return vm_phy_pages_alloc(vm, 1, min_gpa, memslot);
-- 
2.55.0.887.g758fc8c411-goog