1 files changed, 62 insertions, 0 deletions
diff --git a/tools/guest-diag/nvkmstrace.c b/tools/guest-diag/nvkmstrace.c
new file mode 100644
index 0000000..ca72e46
--- /dev/null
+++ b/tools/guest-diag/nvkmstrace.c
@@ -0,0 +1,62 @@
+// nvkmstrace.c - LD_PRELOAD shim: log NVKMS_IOCTL_IOWR commands
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <string.h>
+#include <dlfcn.h>
+#include <sys/ioctl.h>
+
+struct nvkms_ioctl_params {
+	uint32_t cmd;
+	uint32_t size;
+	uint64_t address;
+};
+
+#define NVKMS_REQ 0xC0106D00UL
+
+static int (*real_ioctl)(int, unsigned long, ...);
+
+int ioctl(int fd, unsigned long req, ...)
+{
+	va_list ap;
+	void *arg;
+
+	va_start(ap, req);
+	arg = va_arg(ap, void *);
+	va_end(ap);
+	if (!real_ioctl)
+		real_ioctl = dlsym(RTLD_NEXT, "ioctl");
+	if (req == NVKMS_REQ && arg) {
+		struct nvkms_ioctl_params *p = arg;
+		int rc;
+
+		rc = real_ioctl(fd, req, arg);
+		fprintf(stderr, "NVKMS_IOCTL cmd=%u size=%u addr=%p rc=%d\n",
+			p->cmd, p->size, (void *)(uintptr_t)p->address, rc);
+		if (p->address && p->size) {
+			unsigned char *q = (unsigned char *)(uintptr_t)p->address;
+			unsigned n = p->size < 64 ? p->size : 64, i;
+
+			fprintf(stderr, "  data:");
+			for (i = 0; i < n; i++)
+				fprintf(stderr, " %02x", q[i]);
+			fprintf(stderr, "\n");
+			if (p->size >= 700) {
+				/* reply.status candidates: request = 32 + 4 +
+				 * 4*1 (NvBool=NvU8) + 16*(32+4) = 616 bytes */
+				unsigned o;
+
+				for (o = 600; o <= 700; o += 4) {
+					unsigned v;
+					memcpy(&v, q + o, 4);
+					if (v <= 16)
+						fprintf(stderr, "  small@%u=%u\n",
+							o, v);
+				}
+			}
+		}
+		return rc;
+	}
+	return real_ioctl(fd, req, arg);
+}