Commit 7c236b81 authored by David Matlack's avatar David Matlack Committed by Paolo Bonzini
Browse files

KVM: selftests: Create a separate dirty bitmap per slot 



The calculation to get the per-slot dirty bitmap was incorrect leading
to a buffer overrun. Fix it by splitting out the dirty bitmap into a
separate bitmap per slot.

Fixes: 609e6202 ("KVM: selftests: Support multiple slots in dirty_log_perf_test")
Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
Reviewed-by: default avatarAndrew Jones <drjones@redhat.com>
Message-Id: <20210917173657.44011-4-dmatlack@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9f2fc555

tools/testing/selftests/kvm/dirty_log_perf_test.c

+39 −15
Original line number Diff line number Diff line
@@ -118,42 +118,64 @@ static inline void disable_dirty_logging(struct kvm_vm *vm, int slots) 
	toggle_dirty_logging(vm, slots, false);

}



static void get_dirty_log(struct kvm_vm *vm, int slots, unsigned long *bitmap,

			  uint64_t nr_pages)

static void get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots)

{

	uint64_t slot_pages = nr_pages / slots;

	int i;



	for (i = 0; i < slots; i++) {

		int slot = PERF_TEST_MEM_SLOT_INDEX + i;

		unsigned long *slot_bitmap = bitmap + i * slot_pages;



		kvm_vm_get_dirty_log(vm, slot, slot_bitmap);

		kvm_vm_get_dirty_log(vm, slot, bitmaps[i]);

	}

}



static void clear_dirty_log(struct kvm_vm *vm, int slots, unsigned long *bitmap,

			    uint64_t nr_pages)

static void clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[],

			    int slots, uint64_t pages_per_slot)

{

	uint64_t slot_pages = nr_pages / slots;

	int i;



	for (i = 0; i < slots; i++) {

		int slot = PERF_TEST_MEM_SLOT_INDEX + i;

		unsigned long *slot_bitmap = bitmap + i * slot_pages;



		kvm_vm_clear_dirty_log(vm, slot, slot_bitmap, 0, slot_pages);

		kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot);

	}

}



static unsigned long **alloc_bitmaps(int slots, uint64_t pages_per_slot)

{

	unsigned long **bitmaps;

	int i;



	bitmaps = malloc(slots * sizeof(bitmaps[0]));

	TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array.");



	for (i = 0; i < slots; i++) {

		bitmaps[i] = bitmap_zalloc(pages_per_slot);

		TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap.");

	}



	return bitmaps;

}



static void free_bitmaps(unsigned long *bitmaps[], int slots)

{

	int i;



	for (i = 0; i < slots; i++)

		free(bitmaps[i]);



	free(bitmaps);

}



static void run_test(enum vm_guest_mode mode, void *arg)

{

	struct test_params *p = arg;

	pthread_t *vcpu_threads;

	struct kvm_vm *vm;

	unsigned long *bmap;

	unsigned long **bitmaps;

	uint64_t guest_num_pages;

	uint64_t host_num_pages;

	uint64_t pages_per_slot;

	int vcpu_id;

	struct timespec start;

	struct timespec ts_diff;
@@ -171,7 +193,9 @@ static void run_test(enum vm_guest_mode mode, void *arg) 
	guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm);

	guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);

	host_num_pages = vm_num_host_pages(mode, guest_num_pages);

	bmap = bitmap_zalloc(host_num_pages);

	pages_per_slot = host_num_pages / p->slots;



	bitmaps = alloc_bitmaps(p->slots, pages_per_slot);



	if (dirty_log_manual_caps) {

		cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2;
@@ -239,7 +263,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) 
			iteration, ts_diff.tv_sec, ts_diff.tv_nsec);



		clock_gettime(CLOCK_MONOTONIC, &start);

		get_dirty_log(vm, p->slots, bmap, host_num_pages);

		get_dirty_log(vm, bitmaps, p->slots);

		ts_diff = timespec_elapsed(start);

		get_dirty_log_total = timespec_add(get_dirty_log_total,

						   ts_diff);
@@ -248,7 +272,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) 


		if (dirty_log_manual_caps) {

			clock_gettime(CLOCK_MONOTONIC, &start);

			clear_dirty_log(vm, p->slots, bmap, host_num_pages);

			clear_dirty_log(vm, bitmaps, p->slots, pages_per_slot);

			ts_diff = timespec_elapsed(start);

			clear_dirty_log_total = timespec_add(clear_dirty_log_total,

							     ts_diff);
@@ -281,7 +305,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) 
			clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);

	}



	free(bmap);

	free_bitmaps(bitmaps, p->slots);

	free(vcpu_threads);

	perf_test_destroy_vm(vm);

}