linux-kernel - [PATCH v4 6/7] KVM: selftests: Provide extra mmap flags in vm_mem

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Message-ID: <20250613202315.2790592-7-jthoughton@google.com>
Date: Fri, 13 Jun 2025 20:23:13 +0000
From: James Houghton <jthoughton@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com>
Cc: Vipin Sharma <vipinsh@...gle.com>, David Matlack <dmatlack@...gle.com>, 
	James Houghton <jthoughton@...gle.com>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v4 6/7] KVM: selftests: Provide extra mmap flags in vm_mem_add()

The immediate application here is to allow selftests to pass
MAP_POPULATE (to time fault time without having to allocate guest
memory).

Signed-off-by: James Houghton <jthoughton@...gle.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h    |  3 ++-
 tools/testing/selftests/kvm/lib/kvm_util.c        | 15 +++++++++------
 .../kvm/x86/private_mem_conversions_test.c        |  2 +-
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index bee65ca087217..4aafd5bf786e2 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -629,7 +629,8 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
 	uint32_t flags);
 void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 		uint64_t guest_paddr, uint32_t slot, uint64_t npages,
-		uint32_t flags, int guest_memfd_fd, uint64_t guest_memfd_offset);
+		uint32_t flags, int guest_memfd_fd, uint64_t guest_memfd_offset,
+		int extra_mmap_flags);
 
 #ifndef vm_arch_has_protected_memory
 static inline bool vm_arch_has_protected_memory(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 a055343a7bf75..8157a0fd7f8b3 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -977,13 +977,15 @@ void vm_set_user_memory_region2(struct kvm_vm *vm, uint32_t slot, uint32_t flags
 /* FIXME: This thing needs to be ripped apart and rewritten. */
 void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 		uint64_t guest_paddr, uint32_t slot, uint64_t npages,
-		uint32_t flags, int guest_memfd, uint64_t guest_memfd_offset)
+		uint32_t flags, int guest_memfd, uint64_t guest_memfd_offset,
+		int extra_mmap_flags)
 {
 	int ret;
 	struct userspace_mem_region *region;
 	size_t backing_src_pagesz = get_backing_src_pagesz(src_type);
 	size_t mem_size = npages * vm->page_size;
 	size_t alignment;
+	int mmap_flags;
 
 	TEST_REQUIRE_SET_USER_MEMORY_REGION2();
 
@@ -1066,9 +1068,11 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 		region->fd = kvm_memfd_alloc(region->mmap_size,
 					     src_type == VM_MEM_SRC_SHARED_HUGETLB);
 
+	mmap_flags = vm_mem_backing_src_alias(src_type)->flag |
+		     extra_mmap_flags;
+
 	region->mmap_start = mmap(NULL, region->mmap_size,
-				  PROT_READ | PROT_WRITE,
-				  vm_mem_backing_src_alias(src_type)->flag,
+				  PROT_READ | PROT_WRITE, mmap_flags,
 				  region->fd, 0);
 	TEST_ASSERT(region->mmap_start != MAP_FAILED,
 		    __KVM_SYSCALL_ERROR("mmap()", (int)(unsigned long)MAP_FAILED));
@@ -1143,8 +1147,7 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 	/* If shared memory, create an alias. */
 	if (region->fd >= 0) {
 		region->mmap_alias = mmap(NULL, region->mmap_size,
-					  PROT_READ | PROT_WRITE,
-					  vm_mem_backing_src_alias(src_type)->flag,
+					  PROT_READ | PROT_WRITE, mmap_flags,
 					  region->fd, 0);
 		TEST_ASSERT(region->mmap_alias != MAP_FAILED,
 			    __KVM_SYSCALL_ERROR("mmap()",  (int)(unsigned long)MAP_FAILED));
@@ -1159,7 +1162,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
 				 uint64_t guest_paddr, uint32_t slot,
 				 uint64_t npages, uint32_t flags)
 {
-	vm_mem_add(vm, src_type, guest_paddr, slot, npages, flags, -1, 0);
+	vm_mem_add(vm, src_type, guest_paddr, slot, npages, flags, -1, 0, 0);
 }
 
 /*
diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
index 82a8d88b5338e..637e9e57fce46 100644
--- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
@@ -399,7 +399,7 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, uint32_t
 	for (i = 0; i < nr_memslots; i++)
 		vm_mem_add(vm, src_type, BASE_DATA_GPA + slot_size * i,
 			   BASE_DATA_SLOT + i, slot_size / vm->page_size,
-			   KVM_MEM_GUEST_MEMFD, memfd, slot_size * i);
+			   KVM_MEM_GUEST_MEMFD, memfd, slot_size * i, 0);
 
 	for (i = 0; i < nr_vcpus; i++) {
 		uint64_t gpa =  BASE_DATA_GPA + i * per_cpu_size;
-- 
2.50.0.rc2.692.g299adb8693-goog