[PATCH v4 13/19] KVM: selftests: Add kvm_gettid() wrapper and convert users

[Josh Hilke <jrhilke@google.com>]

Add a KVM wrapper for the gettid() syscall to avoid compilation errors
in versions of Glibc that don't contain gettid(). Convert existing users
of the syscall to use this new wrapper.

This helper will be used in a future change in the KVM IRQ test to
migrate vCPU threads.

No functional changes intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Josh Hilke <jrhilke@google.com>
---
 tools/testing/selftests/kvm/demand_paging_test.c   | 2 +-
 tools/testing/selftests/kvm/include/kvm_syscalls.h | 5 +++++
 tools/testing/selftests/kvm/lib/assert.c           | 8 ++------
 tools/testing/selftests/kvm/lib/test_util.c        | 3 ++-
 tools/testing/selftests/kvm/rseq_test.c            | 2 +-
 5 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
index 0202b78f8680..4ebb2a9c3ba1 100644
--- a/tools/testing/selftests/kvm/demand_paging_test.c
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -57,7 +57,7 @@ static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
 static int handle_uffd_page_request(int uffd_mode, int uffd,
 		struct uffd_msg *msg)
 {
-	pid_t tid = syscall(__NR_gettid);
+	pid_t tid = kvm_gettid();
 	uint64_t addr = msg->arg.pagefault.address;
 	struct timespec start;
 	struct timespec ts_diff;
diff --git a/tools/testing/selftests/kvm/include/kvm_syscalls.h b/tools/testing/selftests/kvm/include/kvm_syscalls.h
index d4e613162bba..522ffff0462c 100644
--- a/tools/testing/selftests/kvm/include/kvm_syscalls.h
+++ b/tools/testing/selftests/kvm/include/kvm_syscalls.h
@@ -73,6 +73,11 @@ static inline int kvm_dup(int fd)
 	return new_fd;
 }
 
+static inline pid_t kvm_gettid(void)
+{
+	return syscall(__NR_gettid);
+}
+
 __KVM_SYSCALL_DEFINE(munmap, 2, void *, mem, size_t, size);
 __KVM_SYSCALL_DEFINE(close, 1, int, fd);
 __KVM_SYSCALL_DEFINE(fallocate, 4, int, fd, int, mode, loff_t, offset, loff_t, len);
diff --git a/tools/testing/selftests/kvm/lib/assert.c b/tools/testing/selftests/kvm/lib/assert.c
index b49690658c60..7914046d334d 100644
--- a/tools/testing/selftests/kvm/lib/assert.c
+++ b/tools/testing/selftests/kvm/lib/assert.c
@@ -10,6 +10,7 @@
 #include <sys/syscall.h>
 
 #include "kselftest.h"
+#include "kvm_syscalls.h"
 
 /* Dumps the current stack trace to stderr. */
 static void __attribute__((noinline)) test_dump_stack(void);
@@ -58,11 +59,6 @@ static void test_dump_stack(void)
 #pragma GCC diagnostic pop
 }
 
-static pid_t _gettid(void)
-{
-	return syscall(SYS_gettid);
-}
-
 void __attribute__((noinline))
 test_assert(bool exp, const char *exp_str,
 	const char *file, unsigned int line, const char *fmt, ...)
@@ -75,7 +71,7 @@ test_assert(bool exp, const char *exp_str,
 		fprintf(stderr, "==== Test Assertion Failure ====\n"
 			"  %s:%u: %s\n"
 			"  pid=%d tid=%d errno=%d - %s\n",
-			file, line, exp_str, getpid(), _gettid(),
+			file, line, exp_str, getpid(), kvm_gettid(),
 			errno, strerror(errno));
 		test_dump_stack();
 		if (fmt) {
diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
index dc47ed9736e9..2006e46926d3 100644
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c
@@ -17,6 +17,7 @@
 #include "linux/kernel.h"
 
 #include "test_util.h"
+#include "kvm_syscalls.h"
 
 sigjmp_buf expect_sigbus_jmpbuf;
 
@@ -395,7 +396,7 @@ long get_run_delay(void)
 	long val[2];
 	FILE *fp;
 
-	sprintf(path, "/proc/%ld/schedstat", syscall(SYS_gettid));
+	sprintf(path, "/proc/%ld/schedstat", (long)kvm_gettid());
 	fp = fopen(path, "r");
 	/* Return MIN_RUN_DELAY_NS upon failure just to be safe */
 	if (fscanf(fp, "%ld %ld ", &val[0], &val[1]) < 2)
diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
index f80ad6b47d16..6510fbfd64f1 100644
--- a/tools/testing/selftests/kvm/rseq_test.c
+++ b/tools/testing/selftests/kvm/rseq_test.c
@@ -244,7 +244,7 @@ int main(int argc, char *argv[])
 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
 
 	pthread_create(&migration_thread, NULL, migration_worker,
-		       (void *)(unsigned long)syscall(SYS_gettid));
+		       (void *)(unsigned long)kvm_gettid());
 
 	if (latency >= 0) {
 		/*
-- 
2.54.0.929.g9b7fa37559-goog