[PATCH] Inform users about busy device assignment attempt

* [PATCH] Inform users about busy device assignment attempt
@ 2009-12-09 20:13 Alexander Graf
  0 siblings, 0 replies; 12+ messages in thread
From: Alexander Graf @ 2009-12-09 20:13 UTC (permalink / raw)
  To: kvm; +Cc: Daniel P. Berrange

When using -pcidevice on a device that is already in use by a kernel driver
all the user gets is the following (very useful) information:

  Failed to assign device "04:00.0" : Device or resource busy
  Failed to deassign device "04:00.0" : Invalid argument
  Error initializing device pci-assign

Since I usually prefer to have my computer do the thinking for me, I figured
it might be a good idea to check and see if a device is actually used by a
driver. If so, tell the user.

So with this patch applied you get the following output:

  Failed to assign device "04:00.0" : Device or resource busy
  *** The driver 'igb' is occupying your device 04:00.0.
  ***
  *** You can try the following commands to free it:
  ***
  *** $ echo "8086 150a" > /sys/bus/pci/drivers/pci-stub/new_id
  *** $ echo "04:00.0" > /sys/bus/pci/drivers/igb/unbind
  *** $ echo "04:00.0" > /sys/bus/pci/drivers/pci-stub/bind
  *** $ echo "8086 150a" > /sys/bus/pci/drivers/pci-stub/remove_id
  ***
  Failed to deassign device "04:00.0" : Invalid argument
  Error initializing device pci-assign

That should keep people like me from doing the most obvious misuses :-).

CC: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

  - add more helpful guidance thanks to Daniel Berrange
---
 hw/device-assignment.c |  106 +++++++++++++++++++++++++++++++++++++----------
 1 files changed, 83 insertions(+), 23 deletions(-)

diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index beb488c..9fbddcf 100644
--- a/hw/device-assignment.c
+++ b/hw/device-assignment.c
@@ -572,6 +572,36 @@ static int assigned_dev_register_regions(PCIRegion *io_regions,
     return 0;
 }
 
+static int get_real_id(const char *devpath, const char *idname, uint16_t *val)
+{
+    FILE *f;
+    char name[128];
+    long id;
+
+    snprintf(name, sizeof(name), "%s%s", devpath, idname);
+    f = fopen(name, "r");
+    if (f == NULL) {
+        fprintf(stderr, "%s: %s: %m\n", __func__, name);
+        return -1;
+    }
+    if (fscanf(f, "%li\n", &id) == 1) {
+        *val = id;
+    }
+    fclose(f);
+
+    return 0;
+}
+
+static int get_real_vendor_id(const char *devpath, uint16_t *val)
+{
+    return get_real_id(devpath, "vendor", val);
+}
+
+static int get_real_device_id(const char *devpath, uint16_t *val)
+{
+    return get_real_id(devpath, "device", val);
+}
+
 static int get_real_device(AssignedDevice *pci_dev, uint8_t r_bus,
                            uint8_t r_dev, uint8_t r_func)
 {
@@ -579,7 +609,7 @@ static int get_real_device(AssignedDevice *pci_dev, uint8_t r_bus,
     int fd, r = 0;
     FILE *f;
     unsigned long long start, end, size, flags;
-    unsigned long id;
+    uint16_t id;
     struct stat statbuf;
     PCIRegion *rp;
     PCIDevRegions *dev = &pci_dev->real_device;
@@ -645,31 +675,21 @@ again:
 
     fclose(f);
 
-    /* read and fill device ID */
-    snprintf(name, sizeof(name), "%svendor", dir);
-    f = fopen(name, "r");
-    if (f == NULL) {
-        fprintf(stderr, "%s: %s: %m\n", __func__, name);
+    /* read and fill vendor ID */
+    r = get_real_vendor_id(dir, &id);
+    if (r) {
         return 1;
     }
-    if (fscanf(f, "%li\n", &id) == 1) {
-	pci_dev->dev.config[0] = id & 0xff;
-	pci_dev->dev.config[1] = (id & 0xff00) >> 8;
-    }
-    fclose(f);
+    pci_dev->dev.config[0] = id & 0xff;
+    pci_dev->dev.config[1] = (id & 0xff00) >> 8;
 
-    /* read and fill vendor ID */
-    snprintf(name, sizeof(name), "%sdevice", dir);
-    f = fopen(name, "r");
-    if (f == NULL) {
-        fprintf(stderr, "%s: %s: %m\n", __func__, name);
+    /* read and fill device ID */
+    r = get_real_device_id(dir, &id);
+    if (r) {
         return 1;
     }
-    if (fscanf(f, "%li\n", &id) == 1) {
-	pci_dev->dev.config[2] = id & 0xff;
-	pci_dev->dev.config[3] = (id & 0xff00) >> 8;
-    }
-    fclose(f);
+    pci_dev->dev.config[2] = id & 0xff;
+    pci_dev->dev.config[3] = (id & 0xff00) >> 8;
 
     /* dealing with virtual function device */
     snprintf(name, sizeof(name), "%sphysfn/", dir);
@@ -747,7 +767,9 @@ static uint32_t calc_assigned_dev_id(uint8_t bus, uint8_t devfn)
 static int assign_device(AssignedDevice *dev)
 {
     struct kvm_assigned_pci_dev assigned_dev_data;
-    int r;
+    char name[128], dir[128], driver[128], *ns;
+    uint16_t vendor_id, device_id;
+    int r, v;
 
     memset(&assigned_dev_data, 0, sizeof(assigned_dev_data));
     assigned_dev_data.assigned_dev_id  =
@@ -769,9 +791,47 @@ static int assign_device(AssignedDevice *dev)
 #endif
 
     r = kvm_assign_pci_device(kvm_context, &assigned_dev_data);
-    if (r < 0)
+    if (r < 0) {
 	fprintf(stderr, "Failed to assign device \"%s\" : %s\n",
                 dev->dev.qdev.id, strerror(-r));
+
+        snprintf(dir, sizeof(dir),
+                 "/sys/bus/pci/devices/0000:%02x:%02x.%x/",
+	         dev->host.bus, dev->host.dev, dev->host.func);
+
+        snprintf(name, sizeof(name), "%sdriver", dir);
+
+        v = readlink(name, driver, sizeof(driver));
+        if ((v <= 0) || !(ns = strrchr(driver, '/'))) {
+            return r;
+        }
+
+        ns++;
+
+        if (get_real_vendor_id(dir, &vendor_id) ||
+            get_real_device_id(dir, &device_id)) {
+            return r;
+        }
+
+        fprintf(stderr, "*** The driver '%s' is occupying your device "
+                        "%02x:%02x.%x.\n",
+                ns, dev->host.bus, dev->host.dev, dev->host.func);
+        fprintf(stderr, "***\n");
+        fprintf(stderr, "*** You can try the following commands to free "
+                        "it:\n");
+        fprintf(stderr, "***\n");
+        fprintf(stderr, "*** $ echo \"%04x %04x\" > /sys/bus/pci/drivers/"
+                        "pci-stub/new_id\n", vendor_id, device_id);
+        fprintf(stderr, "*** $ echo \"%02x:%02x.%x\" > /sys/bus/pci/drivers/%s"
+                        "/unbind\n", dev->host.bus, dev->host.dev,
+                                     dev->host.func, ns);
+        fprintf(stderr, "*** $ echo \"%02x:%02x.%x\" > /sys/bus/pci/drivers/"
+                        "pci-stub/bind\n", dev->host.bus, dev->host.dev,
+                                           dev->host.func);
+        fprintf(stderr, "*** $ echo \"%x %x\" > /sys/bus/pci/drivers/pci-stub"
+                        "/remove_id\n", vendor_id, device_id);
+        fprintf(stderr, "***\n");
+    }
     return r;
 }
 
-- 
1.6.0.2


^ permalink raw reply related	[flat|nested] 12+ messages in thread