[RFC v3 3/3] ktest: sys_move_phys_pages ktest

[Gregory Price]

Implement simple ktest that looks up the physical address via
/proc/self/pagemap and migrates the page based on that information.

Signed-off-by: Gregory Price <gregory.price@xxxxxxxxxxxx>
---
 tools/testing/selftests/mm/migration.c | 99 ++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/tools/testing/selftests/mm/migration.c b/tools/testing/selftests/mm/migration.c
index 6908569ef406..c005c98dbdc1 100644
--- a/tools/testing/selftests/mm/migration.c
+++ b/tools/testing/selftests/mm/migration.c
@@ -5,6 +5,8 @@
  */
 
 #include "../kselftest_harness.h"
+#include <stdint.h>
+#include <stdio.h>
 #include <strings.h>
 #include <pthread.h>
 #include <numa.h>
@@ -14,11 +16,17 @@
 #include <sys/types.h>
 #include <signal.h>
 #include <time.h>
+#include <unistd.h>
 
 #define TWOMEG (2<<20)
 #define RUNTIME (20)
 
+#define GET_BIT(X, Y) ((X & ((uint64_t)1<<Y)) >> Y)
+#define GET_PFN(X) (X & 0x7FFFFFFFFFFFFFull)
 #define ALIGN(x, a) (((x) + (a - 1)) & (~((a) - 1)))
+#define PAGEMAP_ENTRY 8
+const int __endian_bit = 1;
+#define is_bigendian() ((*(char *)&__endian_bit) == 0)
 
 FIXTURE(migration)
 {
@@ -94,6 +102,45 @@ int migrate(uint64_t *ptr, int n1, int n2)
 	return 0;
 }
 
+int migrate_phys(uint64_t paddr, int n1, int n2)
+{
+	int ret, tmp;
+	int status = 0;
+	struct timespec ts1, ts2;
+
+	if (clock_gettime(CLOCK_MONOTONIC, &ts1))
+		return -1;
+
+	while (1) {
+		if (clock_gettime(CLOCK_MONOTONIC, &ts2))
+			return -1;
+
+		if (ts2.tv_sec - ts1.tv_sec >= RUNTIME)
+			return 0;
+
+		/*
+		 * FIXME: move_phys_pages was syscall 462 during RFC.
+		 * Update this when an official syscall number is adopted
+		 * and the libnuma interface is implemented.
+		 */
+		ret = syscall(462, 1, (void **) &paddr, &n2, &status,
+			      MPOL_MF_MOVE_ALL);
+		if (ret) {
+			if (ret > 0)
+				printf("Didn't migrate %d pages\n", ret);
+			else
+				perror("Couldn't migrate pages");
+			return -2;
+		}
+
+		tmp = n2;
+		n2 = n1;
+		n1 = tmp;
+	}
+
+	return 0;
+}
+
 void *access_mem(void *ptr)
 {
 	volatile uint64_t y = 0;
@@ -199,4 +246,56 @@ TEST_F_TIMEOUT(migration, private_anon_thp, 2*RUNTIME)
 		ASSERT_EQ(pthread_cancel(self->threads[i]), 0);
 }
 
+/*
+ * Same as the basic migration, but test move_phys_pages.
+ */
+TEST_F_TIMEOUT(migration, phys_addr, 2*RUNTIME)
+{
+	uint64_t *ptr;
+	uint64_t pagemap_val, paddr, file_offset;
+	unsigned char c_buf[PAGEMAP_ENTRY];
+	int i, c, status;
+	FILE *f;
+
+	if (self->nthreads < 2 || self->n1 < 0 || self->n2 < 0)
+		SKIP(return, "Not enough threads or NUMA nodes available");
+
+	ptr = mmap(NULL, TWOMEG, PROT_READ | PROT_WRITE,
+		MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	ASSERT_NE(ptr, MAP_FAILED);
+
+	memset(ptr, 0xde, TWOMEG);
+
+	/* PFN of ptr from /proc/self/pagemap */
+	f = fopen("/proc/self/pagemap", "rb");
+	file_offset = ((uint64_t)ptr) / getpagesize() * PAGEMAP_ENTRY;
+	status = fseek(f, file_offset, SEEK_SET);
+	ASSERT_EQ(status, 0);
+	for (i = 0; i < PAGEMAP_ENTRY; i++) {
+		c = getc(f);
+		ASSERT_NE(c, EOF);
+		/* handle endiand differences */
+		if (is_bigendian())
+			c_buf[i] = c;
+		else
+			c_buf[PAGEMAP_ENTRY - i - 1] = c;
+	}
+	fclose(f);
+
+	for (i = 0; i < PAGEMAP_ENTRY; i++)
+		pagemap_val = (pagemap_val << 8) + c_buf[i];
+
+	ASSERT_TRUE(GET_BIT(pagemap_val, 63));
+	/* This reports a pfn, we need to shift this by page size */
+	paddr = GET_PFN(pagemap_val) << __builtin_ctz(getpagesize());
+
+	for (i = 0; i < self->nthreads - 1; i++)
+		if (pthread_create(&self->threads[i], NULL, access_mem, ptr))
+			perror("Couldn't create thread");
+
+	ASSERT_EQ(migrate_phys(paddr, self->n1, self->n2), 0);
+	for (i = 0; i < self->nthreads - 1; i++)
+		ASSERT_EQ(pthread_cancel(self->threads[i]), 0);
+}
+
 TEST_HARNESS_MAIN
-- 
2.39.1