diff --git a/devicemodel/hw/pci/passthrough.c b/devicemodel/hw/pci/passthrough.c
index c10206954..27f1c4101 100644
--- a/devicemodel/hw/pci/passthrough.c
+++ b/devicemodel/hw/pci/passthrough.c
@@ -37,6 +37,8 @@
 #include <errno.h>
 #include <pthread.h>
 #include <pciaccess.h>
+#include <fcntl.h>
+#include <unistd.h>
 
 #include "iodev.h"
 #include "vmmapi.h"
@@ -815,7 +817,7 @@ cfginit(struct vmctx *ctx, struct passthru_dev *ptdev, int bus,
 {
 	int irq_type = IRQ_MSI;
 	char reset_path[60];
-	FILE *f;
+	int fd;
 
 	bzero(&ptdev->sel, sizeof(struct pcisel));
 	ptdev->sel.bus = bus;
@@ -835,25 +837,28 @@ cfginit(struct vmctx *ctx, struct passthru_dev *ptdev, int bus,
 		irq_type = IRQ_INTX;
 	}
 
-	/* Check reset method for PCIe dev. If SOS kernel provides 'reset'
-	 * entry in sysfs, related dev has some reset capability, e.g. FLR, or
-	 * secondary bus reset. PCIe dev without any reset capability is
-	 * refused for passthrough.
+	/* If SOS kernel provides 'reset' entry in sysfs, related dev has some
+	 * reset capability, e.g. FLR, or secondary bus reset. We do 2 things:
+	 * - reset each dev before passthrough to achieve valid dev state after
+	 *   UOS reboot
+	 * - refuse to passthrough PCIe dev without any reset capability
 	 */
-	if (ptdev->pcie_cap) {
-		snprintf(reset_path, 40,
-			"/sys/bus/pci/devices/0000:%02x:%02x.%x/reset",
-			bus, slot, func);
+	snprintf(reset_path, 40,
+		"/sys/bus/pci/devices/0000:%02x:%02x.%x/reset",
+		bus, slot, func);
 
-		if ((f = fopen(reset_path, "r")))
-		       fclose(f);
-		else if (errno == ENOENT) {
-			warnx("No reset capability for PCIe %x/%x/%x, "
-					"remove it from ptdev list!!\n",
-					bus, slot, func);
-			if (!no_reset)
-				return -1;
-		}
+	fd = open(reset_path, O_WRONLY);
+	if (fd >= 0) {
+		if (write(fd, "1", 1) < 0)
+			warnx("reset dev %x/%x/%x failed!\n",
+			      bus, slot, func);
+		close(fd);
+	} else if (errno == ENOENT && ptdev->pcie_cap) {
+		warnx("No reset capability for PCIe %x/%x/%x, "
+				"remove it from ptdev list!!\n",
+				bus, slot, func);
+		if (!no_reset)
+			return -1;
 	}
 
 	if (cfginitbar(ctx, ptdev) != 0) {