device-assignment: Rework "name" of assigned pci device

Quoted 11 lines

When assign one PCI device, qemu fail to parse the command line:
qemu-system_x86 -smp 2 -m 1024 -hda /path/to/img -pcidevice host=00:19.0 Error:
qemu-system-x86_64: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. pcidevice argument parse error; please check the help text for usage Could not add assigned device host=00:19.0

https://bugs.launchpad.net/qemu/+bug/597932

This issue caused by qemu-kvm commit b560a9ab9be06afcbb78b3791ab836dad208a239.

Quoted 11 lines · Xudong

Quoted 11 lines

When assign one PCI device, qemu fail to parse the command line:
qemu-system_x86 -smp 2 -m 1024 -hda /path/to/img -pcidevice host=00:19.0 Error:
qemu-system-x86_64: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. pcidevice argument parse error; please check the help text for usage Could not add assigned device host=00:19.0

https://bugs.launchpad.net/qemu/+bug/597932

This issue caused by qemu-kvm commit b560a9ab9be06afcbb78b3791ab836dad208a239.

This patch is a response to the above report.

Thanks,
H.Seto

=====

Because use of some characters in "id" is restricted recently, assigned device start to fail having implicit "id" that uses address string of host device, like "00:19.0" which includes restricted character ':'.

It seems that this implicit "id" is intended to be run as "name" that could be passed with option "-pcidevice ... ,name=..." to specify a string to be used in log outputs. In other words it seems that dev->dev.qdev.id of assigned device had been used to have such "name", that is user-defined string or address string of "host".

The problem is that "name" for specific use is not equal to "id" for universal use. So it is better to remove this tricky mix up here.

This patch introduces new function assigned_dev_name() that returns proper name string for the device.
Now property "name" is explicitly defined in struct AssignedDevice.

When if the device have neither "name" nor "id", address string like "0000:00:19.0" will be created and passed instead. Once created, new field r_name holds the string to be reused and to be released later.

Signed-off-by Hidetoshi Seto <[email protected]>

---
 hw/device-assignment.c |   59 ++++++++++++++++++++++++++++++++++-------------
 hw/device-assignment.h |    2 +
 2 files changed, 44 insertions(+), 17 deletions(-)

hw/device-assignment.c +28 -5

index 585162b..d73516f 100644
@@ -62,6 +62,25 @@ static void assigned_dev_load_option_rom(AssignedDevice *dev);
 
 static void assigned_dev_unregister_msix_mmio(AssignedDevice *dev);
 
+static const char *assigned_dev_name(AssignedDevice *dev)
+{
+    /* use user-defined "name" if specified */
+    if (dev->u_name)
+        return dev->u_name;
+    /* else use "id" if available */
+    if (dev->dev.qdev.id)
+        return dev->dev.qdev.id;
+    /* otherwise use address of host device instead */
+    if (!dev->r_name) {
+        char buf[32];
+
+        snprintf(buf, sizeof(buf), "%04x:%02x:%02x.%01x",
+                 dev->host.seg, dev->host.bus, dev->host.dev, dev->host.func);
+        dev->r_name = qemu_strdup(buf);
+    }
+    return dev->r_name;
+}
+
 static uint32_t guest_to_host_ioport(AssignedDevRegion *region, uint32_t addr)
 {
     return region->u.r_baseport + (addr - region->e_physbase);

@@ -798,6 +817,10 @@ static void free_assigned_device(AssignedDevice *dev)
             dev->real_device.config_fd = 0;
         }
 
+    if (dev->r_name) {
+        qemu_free(dev->r_name);
+    }
+
 #ifdef KVM_CAP_IRQ_ROUTING
         free_dev_irq_entries(dev);
 #endif

@@ -885,7 +908,7 @@ static int assign_device(AssignedDevice *dev)
     if (dev->use_iommu) {
         if (!kvm_check_extension(kvm_state, KVM_CAP_IOMMU)) {
             fprintf(stderr, "No IOMMU found.  Unable to assign device \"%s\"\n",
-                    dev->dev.qdev.id);
+                    assigned_dev_name(dev));
             return -ENODEV;
         }
         assigned_dev_data.flags |= KVM_DEV_ASSIGN_ENABLE_IOMMU;

@@ -897,7 +920,7 @@ static int assign_device(AssignedDevice *dev)
     r = kvm_assign_pci_device(kvm_context, &assigned_dev_data);
     if (r < 0) {
         fprintf(stderr, "Failed to assign device \"%s\" : %s\n",
-                dev->dev.qdev.id, strerror(-r));
+                assigned_dev_name(dev), strerror(-r));
 
         switch (r) {
             case -EBUSY:

@@ -953,7 +976,7 @@ static int assign_irq(AssignedDevice *dev)
     r = kvm_assign_irq(kvm_context, &assigned_irq_data);
     if (r < 0) {
         fprintf(stderr, "Failed to assign irq for \"%s\": %s\n",
-                dev->dev.qdev.id, strerror(-r));
+                assigned_dev_name(dev), strerror(-r));
         fprintf(stderr, "Perhaps you are assigning a device "
                 "that shares an IRQ with another device?\n");
         return r;

@@ -977,7 +1000,7 @@ static void deassign_device(AssignedDevice *dev)
     r = kvm_deassign_pci_device(kvm_context, &assigned_dev_data);
     if (r < 0)
 	fprintf(stderr, "Failed to deassign device \"%s\" : %s\n",
-                dev->dev.qdev.id, strerror(-r));
+                assigned_dev_name(dev), strerror(-r));
 #endif
 }
 

@@ -1421,7 +1444,7 @@ static int assigned_initfn(struct PCIDevice *pci_dev)
     if (get_real_device(dev, dev->host.seg, dev->host.bus,
                         dev->host.dev, dev->host.func)) {
         error_report("pci-assign: Error: Couldn't get real device (%s)!",
-                     dev->dev.qdev.id);
+                     assigned_dev_name(dev));
         goto out;
     }
 

@@ -1487,8 +1510,9 @@ static int parse_hostaddr(DeviceState *dev, Property *prop, const char *str)
     PCIHostDevice *ptr = qdev_get_prop_ptr(dev, prop);

hw/device-assignment.c +3 -1

 PropertyInfo qdev_prop_hostaddr = {

@@ -1520,6 +1545,7 @@ static PCIDeviceInfo assign_info = {
         DEFINE_PROP("host", AssignedDevice, host, qdev_prop_hostaddr, PCIHostDevice),
         DEFINE_PROP_UINT32("iommu", AssignedDevice, use_iommu, 1),
         DEFINE_PROP_STRING("configfd", AssignedDevice, configfd_name),
+        DEFINE_PROP_STRING("name", AssignedDevice, u_name),
         DEFINE_PROP_END_OF_LIST(),
     },
 };

@@ -1545,24 +1571,25 @@ device_init(assign_register_devices)
 QemuOpts *add_assigned_device(const char *arg)
 {
     QemuOpts *opts = NULL;
-    char host[64], id[64], dma[8];
+    char host[64], buf[64], dma[8];
     int r;
 
+    /* "host" must be with -pcidevice */
     r = get_param_value(host, sizeof(host), "host", arg);

hw/device-assignment.c +5 -2

     if (!opts)
         goto bad;
     qemu_opt_set(opts, "driver", "pci-assign");
     qemu_opt_set(opts, "host", host);
 
+    /* Log outputs use "name" if specified */
+    r = get_param_value(buf, sizeof(buf), "name", arg);
+    if (r)
+        qemu_opt_set(opts, "name", buf);
+
 #ifdef KVM_CAP_IOMMU
     r = get_param_value(dma, sizeof(dma), "dma", arg);
     if (r && !strncmp(dma, "none", 4))

@@ -1574,8 +1601,6 @@ QemuOpts *add_assigned_device(const char *arg)
 bad:
     fprintf(stderr, "pcidevice argument parse error; "
             "please check the help text for usage\n");
-    if (opts)
-        qemu_opts_del(opts);
     return NULL;
 }
 

hw/device-assignment.h +0 -0

index 4e7fe87..fb00e29 100644

Quoted 24 lines · Hidetoshi Seto

Quoted 11 lines · Xudong

Quoted 11 lines

When assign one PCI device, qemu fail to parse the command line:
qemu-system_x86 -smp 2 -m 1024 -hda /path/to/img -pcidevice host=00:19.0 Error:
qemu-system-x86_64: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. pcidevice argument parse error; please check the help text for usage Could not add assigned device host=00:19.0

https://bugs.launchpad.net/qemu/+bug/597932

This issue caused by qemu-kvm commit b560a9ab9be06afcbb78b3791ab836dad208a239.

This patch is a response to the above report.

Thanks,
H.Seto

=====

Because use of some characters in "id" is restricted recently, assigned device start to fail having implicit "id" that uses address string of host device, like "00:19.0" which includes restricted character ':'.

Quoted 5 lines

It seems that this implicit "id" is intended to be run as "name" that could be passed with option "-pcidevice ... ,name=..." to specify a string to be used in log outputs. In other words it seems that dev->dev.qdev.id of assigned device had been used to have such "name", that is user-defined string or address string of "host".

As far as I can tell, option "name" is just a leftover from pre-qdev days, kept for compatibility.

Quoted 7 lines

The problem is that "name" for specific use is not equal to "id" for universal use. So it is better to remove this tricky mix up here.

This patch introduces new function assigned_dev_name() that returns proper name string for the device.
Now property "name" is explicitly defined in struct AssignedDevice.

Quoted 5 lines

When if the device have neither "name" nor "id", address string like "0000:00:19.0" will be created and passed instead. Once created, new field r_name holds the string to be reused and to be released later.

Signed-off-by Hidetoshi Seto <[email protected]>

Comments inline.

Quoted 95 lines

---
 hw/device-assignment.c |   59 ++++++++++++++++++++++++++++++++++-------------
 hw/device-assignment.h |    2 +
 2 files changed, 44 insertions(+), 17 deletions(-)

hw/device-assignment.c +28 -5

index 585162b..d73516f 100644
@@ -62,6 +62,25 @@ static void assigned_dev_load_option_rom(AssignedDevice *dev);
 
 static void assigned_dev_unregister_msix_mmio(AssignedDevice *dev);
 
+static const char *assigned_dev_name(AssignedDevice *dev)
+{
+    /* use user-defined "name" if specified */
+    if (dev->u_name)
+        return dev->u_name;
+    /* else use "id" if available */
+    if (dev->dev.qdev.id)
+        return dev->dev.qdev.id;
+    /* otherwise use address of host device instead */
+    if (!dev->r_name) {
+        char buf[32];
+
+        snprintf(buf, sizeof(buf), "%04x:%02x:%02x.%01x",
+                 dev->host.seg, dev->host.bus, dev->host.dev, dev->host.func);
+        dev->r_name = qemu_strdup(buf);
+    }
+    return dev->r_name;
+}
+
 static uint32_t guest_to_host_ioport(AssignedDevRegion *region, uint32_t addr)
 {
     return region->u.r_baseport + (addr - region->e_physbase);

@@ -798,6 +817,10 @@ static void free_assigned_device(AssignedDevice *dev)
             dev->real_device.config_fd = 0;
         }
 
+    if (dev->r_name) {
+        qemu_free(dev->r_name);
+    }
+
 #ifdef KVM_CAP_IRQ_ROUTING
         free_dev_irq_entries(dev);
 #endif

@@ -885,7 +908,7 @@ static int assign_device(AssignedDevice *dev)
     if (dev->use_iommu) {
         if (!kvm_check_extension(kvm_state, KVM_CAP_IOMMU)) {
             fprintf(stderr, "No IOMMU found.  Unable to assign device \"%s\"\n",
-                    dev->dev.qdev.id);
+                    assigned_dev_name(dev));
             return -ENODEV;
         }
         assigned_dev_data.flags |= KVM_DEV_ASSIGN_ENABLE_IOMMU;

@@ -897,7 +920,7 @@ static int assign_device(AssignedDevice *dev)
     r = kvm_assign_pci_device(kvm_context, &assigned_dev_data);
     if (r < 0) {
         fprintf(stderr, "Failed to assign device \"%s\" : %s\n",
-                dev->dev.qdev.id, strerror(-r));
+                assigned_dev_name(dev), strerror(-r));
 
         switch (r) {
             case -EBUSY:

@@ -953,7 +976,7 @@ static int assign_irq(AssignedDevice *dev)
     r = kvm_assign_irq(kvm_context, &assigned_irq_data);
     if (r < 0) {
         fprintf(stderr, "Failed to assign irq for \"%s\": %s\n",
-                dev->dev.qdev.id, strerror(-r));
+                assigned_dev_name(dev), strerror(-r));
         fprintf(stderr, "Perhaps you are assigning a device "
                 "that shares an IRQ with another device?\n");
         return r;

@@ -977,7 +1000,7 @@ static void deassign_device(AssignedDevice *dev)
     r = kvm_deassign_pci_device(kvm_context, &assigned_dev_data);
     if (r < 0)
 	fprintf(stderr, "Failed to deassign device \"%s\" : %s\n",
-                dev->dev.qdev.id, strerror(-r));
+                assigned_dev_name(dev), strerror(-r));
 #endif
 }
 

@@ -1421,7 +1444,7 @@ static int assigned_initfn(struct PCIDevice *pci_dev)
     if (get_real_device(dev, dev->host.seg, dev->host.bus,
                         dev->host.dev, dev->host.func)) {
         error_report("pci-assign: Error: Couldn't get real device (%s)!",
-                     dev->dev.qdev.id);
+                     assigned_dev_name(dev));
         goto out;
     }
 

@@ -1487,8 +1510,9 @@ static int parse_hostaddr(DeviceState *dev, Property *prop, const char *str)
     PCIHostDevice *ptr = qdev_get_prop_ptr(dev, prop);
     int rc;
 

hw/device-assignment.c static int parse_hostaddr(DeviceState *dev, Property *prop, const char *str) · line 1518

Quoted 8 lines

hw/device-assignment.c +3 -2

-    rc = pci_parse_host_devaddr(str, &ptr->seg, &ptr->bus, &ptr->dev, &ptr->func);
-    if (rc != 0)
+    rc = pci_parse_host_devaddr(str,
+                                &ptr->seg, &ptr->bus, &ptr->dev, &ptr->func);
+    if (rc)
         return -1;
     return 0;
 }

This is style cleanup. Please don't mix that with functional changes in the same patch.

hw/device-assignment.c static int print_hostaddr(DeviceState *dev, Property *prop, char *dest, size_t l · line 1526

Quoted 8 lines

hw/device-assignment.c +2 -1

@@ -1497,7 +1521,8 @@ static int print_hostaddr(DeviceState *dev, Property *prop, char *dest, size_t l
 {
     PCIHostDevice *ptr = qdev_get_prop_ptr(dev, prop);
 
-    return snprintf(dest, len, "%02x:%02x.%x", ptr->bus, ptr->dev, ptr->func);
+    return snprintf(dest, len, "%04x:%02x:%02x.%x",
+                    ptr->seg, ptr->bus, ptr->dev, ptr->func);
 }

Properly covering seg here is an unrelated fix. Separate patch please.

Quoted 28 lines

hw/device-assignment.c +3 -6

 PropertyInfo qdev_prop_hostaddr = {

@@ -1520,6 +1545,7 @@ static PCIDeviceInfo assign_info = {
         DEFINE_PROP("host", AssignedDevice, host, qdev_prop_hostaddr, PCIHostDevice),
         DEFINE_PROP_UINT32("iommu", AssignedDevice, use_iommu, 1),
         DEFINE_PROP_STRING("configfd", AssignedDevice, configfd_name),
+        DEFINE_PROP_STRING("name", AssignedDevice, u_name),
         DEFINE_PROP_END_OF_LIST(),
     },
 };

@@ -1545,24 +1571,25 @@ device_init(assign_register_devices)
 QemuOpts *add_assigned_device(const char *arg)
 {
     QemuOpts *opts = NULL;
-    char host[64], id[64], dma[8];
+    char host[64], buf[64], dma[8];
     int r;
 
+    /* "host" must be with -pcidevice */
     r = get_param_value(host, sizeof(host), "host", arg);
     if (!r)
          goto bad;
-    r = get_param_value(id, sizeof(id), "id", arg);
-    if (!r)
-        r = get_param_value(id, sizeof(id), "name", arg);
-    if (!r)
-        r = get_param_value(id, sizeof(id), "host", arg);
 

hw/device-assignment.c device_init(assign_register_devices) · line 1582

Quoted 2 lines

hw/device-assignment.c +1 -1

-    opts = qemu_opts_create(&qemu_device_opts, id, 0);
+    opts = qemu_opts_create(&qemu_device_opts, NULL, 0);

I think you break option id here. Its value must become the qdev ID, visible in info qtree and usable as argument to device_del. And if option id is missing, option name must become the qdev ID, for backwards compatibility.

Quoted 22 lines

hw/device-assignment.c +5 -2

     if (!opts)
         goto bad;
     qemu_opt_set(opts, "driver", "pci-assign");
     qemu_opt_set(opts, "host", host);
 
+    /* Log outputs use "name" if specified */
+    r = get_param_value(buf, sizeof(buf), "name", arg);
+    if (r)
+        qemu_opt_set(opts, "name", buf);
+
 #ifdef KVM_CAP_IOMMU
     r = get_param_value(dma, sizeof(dma), "dma", arg);
     if (r && !strncmp(dma, "none", 4))

@@ -1574,8 +1601,6 @@ QemuOpts *add_assigned_device(const char *arg)
 bad:
     fprintf(stderr, "pcidevice argument parse error; "
             "please check the help text for usage\n");
-    if (opts)
-        qemu_opts_del(opts);
     return NULL;
 }
 

hw/device-assignment.h typedef struct AssignedDevice { · line 93

Quoted 13 lines

hw/device-assignment.h +2 -0

index 4e7fe87..fb00e29 100644
@@ -86,6 +86,8 @@ typedef struct AssignedDevice {
     unsigned int h_segnr;
     unsigned char h_busnr;
     unsigned int h_devfn;
+    char *u_name;
+    char *r_name;
     int irq_requested_type;
     int bound;
     struct {

Do you really need u_name? There's id.

Thanks Markus,

Quoted 32 lines · Markus Armbruster

Quoted 29 lines · Hidetoshi Seto

Quoted 11 lines · Xudong

Quoted 11 lines

When assign one PCI device, qemu fail to parse the command line:
qemu-system_x86 -smp 2 -m 1024 -hda /path/to/img -pcidevice host=00:19.0 Error:
qemu-system-x86_64: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. pcidevice argument parse error; please check the help text for usage Could not add assigned device host=00:19.0

https://bugs.launchpad.net/qemu/+bug/597932

This issue caused by qemu-kvm commit b560a9ab9be06afcbb78b3791ab836dad208a239.

This patch is a response to the above report.

Thanks,
H.Seto

=====

Because use of some characters in "id" is restricted recently, assigned device start to fail having implicit "id" that uses address string of host device, like "00:19.0" which includes restricted character ':'.

It seems that this implicit "id" is intended to be run as "name" that could be passed with option "-pcidevice ... ,name=..." to specify a string to be used in log outputs. In other words it seems that dev->dev.qdev.id of assigned device had been used to have such "name", that is user-defined string or address string of "host".

Quoted 2 lines

As far as I can tell, option "name" is just a leftover from pre-qdev days, kept for compatibility.

Yea, I see.
I don't know well about the history of such pre-qdev days...

Quoted 10 lines

Quoted 10 lines

The problem is that "name" for specific use is not equal to "id" for universal use. So it is better to remove this tricky mix up here.

This patch introduces new function assigned_dev_name() that returns proper name string for the device.
Now property "name" is explicitly defined in struct AssignedDevice.

When if the device have neither "name" nor "id", address string like "0000:00:19.0" will be created and passed instead. Once created, new field r_name holds the string to be reused and to be released later.

Quoted 26 lines

Quoted 26 lines

hw/device-assignment.c +3 -6

@@ -1520,6 +1545,7 @@ static PCIDeviceInfo assign_info = {
         DEFINE_PROP("host", AssignedDevice, host, qdev_prop_hostaddr, PCIHostDevice),
         DEFINE_PROP_UINT32("iommu", AssignedDevice, use_iommu, 1),
         DEFINE_PROP_STRING("configfd", AssignedDevice, configfd_name),
+        DEFINE_PROP_STRING("name", AssignedDevice, u_name),
         DEFINE_PROP_END_OF_LIST(),
     },
 };

@@ -1545,24 +1571,25 @@ device_init(assign_register_devices)
 QemuOpts *add_assigned_device(const char *arg)
 {
     QemuOpts *opts = NULL;
-    char host[64], id[64], dma[8];
+    char host[64], buf[64], dma[8];
     int r;
 
+    /* "host" must be with -pcidevice */
     r = get_param_value(host, sizeof(host), "host", arg);
     if (!r)
          goto bad;
-    r = get_param_value(id, sizeof(id), "id", arg);
-    if (!r)
-        r = get_param_value(id, sizeof(id), "name", arg);
-    if (!r)
-        r = get_param_value(id, sizeof(id), "host", arg);
 

Quoted 7 lines

hw/device-assignment.c device_init(assign_register_devices) · line 1582

Quoted 2 lines

hw/device-assignment.c +1 -1

-    opts = qemu_opts_create(&qemu_device_opts, id, 0);
+    opts = qemu_opts_create(&qemu_device_opts, NULL, 0);

I think you break option id here. Its value must become the qdev ID, visible in info qtree and usable as argument to device_del. And if option id is missing, option name must become the qdev ID, for backwards compatibility.

Ah, I missed to check hot-add path - I had wonder why id could be here since I could not find documents that mentions use of id with -pcidevice.

So, I should use id here if specified. That's right,

But in case if id is missing and name is specified, I think there is no reason that the characters in name should be restricted in same manner with that in id.

In case that there is neither id nor name but host (in fact it is original case) now ID "BB:DD.F" (like 00:19.0) will be rejected (because it starts with digit, plus it uses restricted ':').

In other words, your change already breaks backwards compatibility because it prevents "-pcidevice host=BB:DD.F" from creating ID "BB:DD.F" that might be used as argument to device_del etc.

BTW I think "-pcidevice host=BB:DD.F,name=1394" is an another litmus test.

My opinion is that we should not do any fall back here if id is missing. Using name or host as id is wrong, since it could be said that in such case id is specified as "unspecified".

Quoted 22 lines

Quoted 22 lines

hw/device-assignment.c +5 -2

     if (!opts)
         goto bad;
     qemu_opt_set(opts, "driver", "pci-assign");
     qemu_opt_set(opts, "host", host);
 
+    /* Log outputs use "name" if specified */
+    r = get_param_value(buf, sizeof(buf), "name", arg);
+    if (r)
+        qemu_opt_set(opts, "name", buf);
+
 #ifdef KVM_CAP_IOMMU
     r = get_param_value(dma, sizeof(dma), "dma", arg);
     if (r && !strncmp(dma, "none", 4))

@@ -1574,8 +1601,6 @@ QemuOpts *add_assigned_device(const char *arg)
 bad:
     fprintf(stderr, "pcidevice argument parse error; "
             "please check the help text for usage\n");
-    if (opts)
-        qemu_opts_del(opts);
     return NULL;
 }
 

Quoted 15 lines

hw/device-assignment.h typedef struct AssignedDevice { · line 93

Quoted 13 lines

hw/device-assignment.h +2 -0

index 4e7fe87..fb00e29 100644
@@ -86,6 +86,8 @@ typedef struct AssignedDevice {
     unsigned int h_segnr;
     unsigned char h_busnr;
     unsigned int h_devfn;
+    char *u_name;
+    char *r_name;
     int irq_requested_type;
     int bound;
     struct {

Do you really need u_name? There's id.

For backwards compatibility, and to have name string with no restriction, it is needed, I think.

(Personally speaking I agree to recommend '-device + id=' instead of
'-pcidevice + name=')

Summary: upstream qemu commit b560a9ab broke -pcidevice and pci_add host in two ways:

* Use without options id and name is broken when option host contains ':'. That's because id defaults to host. I recommend to fix it
incompatibly: don't default id to host. The alternative is to get upstream qemu to accept ':' in qdev IDs again.

* Funny characters in option name no longer work. Same as funny characters in id options all over the place. Intentional change. I recommend to do nothing.

Details inline.

Quoted 35 lines · Hidetoshi Seto

Thanks Markus,

Quoted 32 lines · Markus Armbruster

Quoted 29 lines · Hidetoshi Seto

Quoted 11 lines · Xudong

Quoted 11 lines

When assign one PCI device, qemu fail to parse the command line:
qemu-system_x86 -smp 2 -m 1024 -hda /path/to/img -pcidevice host=00:19.0 Error:
qemu-system-x86_64: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. pcidevice argument parse error; please check the help text for usage Could not add assigned device host=00:19.0

https://bugs.launchpad.net/qemu/+bug/597932

This issue caused by qemu-kvm commit b560a9ab9be06afcbb78b3791ab836dad208a239.

This patch is a response to the above report.

Thanks,
H.Seto

=====

Because use of some characters in "id" is restricted recently, assigned device start to fail having implicit "id" that uses address string of host device, like "00:19.0" which includes restricted character ':'.

It seems that this implicit "id" is intended to be run as "name" that could be passed with option "-pcidevice ... ,name=..." to specify a string to be used in log outputs. In other words it seems that dev->dev.qdev.id of assigned device had been used to have such "name", that is user-defined string or address string of "host".

Quoted 5 lines

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As far as I can tell, option "name" is just a leftover from pre-qdev days, kept for compatibility.

Yea, I see.
I don't know well about the history of such pre-qdev days...

It's often useful to examine history to figure out what a piece of code attempts to accomplish. git-blame and git-log are your friends :)

Quoted 10 lines

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The problem is that "name" for specific use is not equal to "id" for universal use. So it is better to remove this tricky mix up here.

This patch introduces new function assigned_dev_name() that returns proper name string for the device.
Now property "name" is explicitly defined in struct AssignedDevice.

When if the device have neither "name" nor "id", address string like "0000:00:19.0" will be created and passed instead. Once created, new field r_name holds the string to be reused and to be released later.

[...]

Quoted 51 lines

Quoted 26 lines

Quoted 26 lines

hw/device-assignment.c +3 -6

@@ -1520,6 +1545,7 @@ static PCIDeviceInfo assign_info = {
         DEFINE_PROP("host", AssignedDevice, host, qdev_prop_hostaddr, PCIHostDevice),
         DEFINE_PROP_UINT32("iommu", AssignedDevice, use_iommu, 1),
         DEFINE_PROP_STRING("configfd", AssignedDevice, configfd_name),
+        DEFINE_PROP_STRING("name", AssignedDevice, u_name),
         DEFINE_PROP_END_OF_LIST(),
     },
 };

@@ -1545,24 +1571,25 @@ device_init(assign_register_devices)
 QemuOpts *add_assigned_device(const char *arg)
 {
     QemuOpts *opts = NULL;
-    char host[64], id[64], dma[8];
+    char host[64], buf[64], dma[8];
     int r;
 
+    /* "host" must be with -pcidevice */
     r = get_param_value(host, sizeof(host), "host", arg);
     if (!r)
          goto bad;
-    r = get_param_value(id, sizeof(id), "id", arg);
-    if (!r)
-        r = get_param_value(id, sizeof(id), "name", arg);
-    if (!r)
-        r = get_param_value(id, sizeof(id), "host", arg);
 

Quoted 7 lines

hw/device-assignment.c device_init(assign_register_devices) · line 1582

Quoted 2 lines

hw/device-assignment.c +1 -1

-    opts = qemu_opts_create(&qemu_device_opts, id, 0);
+    opts = qemu_opts_create(&qemu_device_opts, NULL, 0);

I think you break option id here. Its value must become the qdev ID, visible in info qtree and usable as argument to device_del. And if option id is missing, option name must become the qdev ID, for backwards compatibility.

Ah, I missed to check hot-add path - I had wonder why id could be here since I could not find documents that mentions use of id with -pcidevice.

So, I should use id here if specified. That's right,

But in case if id is missing and name is specified, I think there is no reason that the characters in name should be restricted in same manner with that in id.

In case that there is neither id nor name but host (in fact it is original case) now ID "BB:DD.F" (like 00:19.0) will be rejected (because it starts with digit, plus it uses restricted ':').

In other words, your change already breaks backwards compatibility because it prevents "-pcidevice host=BB:DD.F" from creating ID "BB:DD.F" that might be used as argument to device_del etc.

Quoted 5 lines

BTW I think "-pcidevice host=BB:DD.F,name=1394" is an another litmus test.

My opinion is that we should not do any fall back here if id is missing. Using name or host as id is wrong, since it could be said that in such case id is specified as "unspecified".

Commit b560a9ab broke name the same way it broke any other qdev ID: you can't use funny characters anymore. Intentional change.

name exists for backward compatibility only. Changing its meaning incompatibly (namely not to affect qdev ID) makes no sense to me; we could just as well remove it then.

The commit also broke defaulting id to host, because host can contain the funny character ':'. I wasn't aware of that when I made the change in upstream qemu (-pcidevice is qemu-kvm only, easy to lose sight of it). The one way to fix this compatibly is to get upstream qemu accept ':' in IDs.

If we're fine with incompatible change here, or upstream qemu forces the incompatible change on us by refusing to accept ':', then I think we should simply drop the fallback.

We could continue to fall back to strings that pass id_wellformed(). Don't like it.

Without the fallback, there is no use of name left. Your patch creates a new one: use it instead of qdev ID in messages. Why is that useful?

Quoted 38 lines

Quoted 37 lines

Quoted 27 lines

hw/device-assignment.c +5 -2

     if (!opts)
         goto bad;
     qemu_opt_set(opts, "driver", "pci-assign");
     qemu_opt_set(opts, "host", host);
 
+    /* Log outputs use "name" if specified */
+    r = get_param_value(buf, sizeof(buf), "name", arg);
+    if (r)
+        qemu_opt_set(opts, "name", buf);
+
 #ifdef KVM_CAP_IOMMU
     r = get_param_value(dma, sizeof(dma), "dma", arg);
     if (r && !strncmp(dma, "none", 4))

@@ -1574,8 +1601,6 @@ QemuOpts *add_assigned_device(const char *arg)
 bad:
     fprintf(stderr, "pcidevice argument parse error; "
             "please check the help text for usage\n");
-    if (opts)
-        qemu_opts_del(opts);
     return NULL;
 }
 

hw/device-assignment.h +0 -0

index 4e7fe87..fb00e29 100644

hw/device-assignment.h typedef struct AssignedDevice { · line 93

Quoted 8 lines

hw/device-assignment.h +2 -0

@@ -86,6 +86,8 @@ typedef struct AssignedDevice {
     unsigned int h_segnr;
     unsigned char h_busnr;
     unsigned int h_devfn;
+    char *u_name;
+    char *r_name;
     int irq_requested_type;
     int bound;
     struct {

Do you really need u_name? There's id.

Quoted 2 lines

For backwards compatibility, and to have name string with no restriction, it is needed, I think.

Why do we need a name string for -pcidevice, but not for other devices?

Quoted 2 lines

(Personally speaking I agree to recommend '-device + id=' instead of
'-pcidevice + name=')

Quoted 11 lines · Markus Armbruster

Summary: upstream qemu commit b560a9ab broke -pcidevice and pci_add host in two ways:

* Use without options id and name is broken when option host contains ':'. That's because id defaults to host. I recommend to fix it
incompatibly: don't default id to host. The alternative is to get upstream qemu to accept ':' in qdev IDs again.

* Funny characters in option name no longer work. Same as funny characters in id options all over the place. Intentional change. I recommend to do nothing.

Thanks a lot.
I'm not a person in really need, so now I'm going to follow your recommendation.

Quoted 39 lines

Details inline.

Quoted 35 lines · Hidetoshi Seto

Thanks Markus,

Quoted 32 lines · Markus Armbruster

Quoted 29 lines · Hidetoshi Seto

Quoted 11 lines · Xudong

Quoted 11 lines

When assign one PCI device, qemu fail to parse the command line:
qemu-system_x86 -smp 2 -m 1024 -hda /path/to/img -pcidevice host=00:19.0 Error:
qemu-system-x86_64: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. pcidevice argument parse error; please check the help text for usage Could not add assigned device host=00:19.0

https://bugs.launchpad.net/qemu/+bug/597932

This issue caused by qemu-kvm commit b560a9ab9be06afcbb78b3791ab836dad208a239.

This patch is a response to the above report.

Thanks,
H.Seto

=====

Because use of some characters in "id" is restricted recently, assigned device start to fail having implicit "id" that uses address string of host device, like "00:19.0" which includes restricted character ':'.

It seems that this implicit "id" is intended to be run as "name" that could be passed with option "-pcidevice ... ,name=..." to specify a string to be used in log outputs. In other words it seems that dev->dev.qdev.id of assigned device had been used to have such "name", that is user-defined string or address string of "host".

Quoted 8 lines

Quoted 5 lines

Quoted 2 lines

As far as I can tell, option "name" is just a leftover from pre-qdev days, kept for compatibility.

Yea, I see.
I don't know well about the history of such pre-qdev days...

It's often useful to examine history to figure out what a piece of code attempts to accomplish. git-blame and git-log are your friends :)

I often play with git-log, however I have a little trouble here since qemu tree is too young.

Quoted 68 lines

Quoted 10 lines

Quoted 10 lines

Quoted 10 lines

The problem is that "name" for specific use is not equal to "id" for universal use. So it is better to remove this tricky mix up here.

This patch introduces new function assigned_dev_name() that returns proper name string for the device.
Now property "name" is explicitly defined in struct AssignedDevice.

When if the device have neither "name" nor "id", address string like "0000:00:19.0" will be created and passed instead. Once created, new field r_name holds the string to be reused and to be released later.

[...]

Quoted 51 lines

Quoted 26 lines

Quoted 26 lines

hw/device-assignment.c +3 -6

@@ -1520,6 +1545,7 @@ static PCIDeviceInfo assign_info = {
         DEFINE_PROP("host", AssignedDevice, host, qdev_prop_hostaddr, PCIHostDevice),
         DEFINE_PROP_UINT32("iommu", AssignedDevice, use_iommu, 1),
         DEFINE_PROP_STRING("configfd", AssignedDevice, configfd_name),
+        DEFINE_PROP_STRING("name", AssignedDevice, u_name),
         DEFINE_PROP_END_OF_LIST(),
     },
 };

@@ -1545,24 +1571,25 @@ device_init(assign_register_devices)
 QemuOpts *add_assigned_device(const char *arg)
 {
     QemuOpts *opts = NULL;
-    char host[64], id[64], dma[8];
+    char host[64], buf[64], dma[8];
     int r;
 
+    /* "host" must be with -pcidevice */
     r = get_param_value(host, sizeof(host), "host", arg);
     if (!r)
          goto bad;
-    r = get_param_value(id, sizeof(id), "id", arg);
-    if (!r)
-        r = get_param_value(id, sizeof(id), "name", arg);
-    if (!r)
-        r = get_param_value(id, sizeof(id), "host", arg);
 

Quoted 7 lines

hw/device-assignment.c device_init(assign_register_devices) · line 1582

Quoted 2 lines

hw/device-assignment.c +1 -1

-    opts = qemu_opts_create(&qemu_device_opts, id, 0);
+    opts = qemu_opts_create(&qemu_device_opts, NULL, 0);

I think you break option id here. Its value must become the qdev ID, visible in info qtree and usable as argument to device_del. And if option id is missing, option name must become the qdev ID, for backwards compatibility.

Ah, I missed to check hot-add path - I had wonder why id could be here since I could not find documents that mentions use of id with -pcidevice.

So, I should use id here if specified. That's right,

But in case if id is missing and name is specified, I think there is no reason that the characters in name should be restricted in same manner with that in id.

In case that there is neither id nor name but host (in fact it is original case) now ID "BB:DD.F" (like 00:19.0) will be rejected (because it starts with digit, plus it uses restricted ':').

In other words, your change already breaks backwards compatibility because it prevents "-pcidevice host=BB:DD.F" from creating ID "BB:DD.F" that might be used as argument to device_del etc.

Quoted 5 lines

BTW I think "-pcidevice host=BB:DD.F,name=1394" is an another litmus test.

My opinion is that we should not do any fall back here if id is missing. Using name or host as id is wrong, since it could be said that in such case id is specified as "unspecified".

Quoted 6 lines

Commit b560a9ab broke name the same way it broke any other qdev ID: you can't use funny characters anymore. Intentional change.

name exists for backward compatibility only. Changing its meaning incompatibly (namely not to affect qdev ID) makes no sense to me; we could just as well remove it then.

Well, I think I'll very happy if name have gone.

What I'm concerning here is the impact of incompatible brought by commit b560a9ab. It makes some old settings/config files to fail creating VMs.

My first stand point was "it is better to allow old configs with no changes to work in some degree" ... But now I understand that "original ID change already has considerable impact on such old configs and it will force rewrite on them anyway, so this patch for minor compatibility of 'name' will never be any help".

Quoted 5 lines

The commit also broke defaulting id to host, because host can contain the funny character ':'. I wasn't aware of that when I made the change in upstream qemu (-pcidevice is qemu-kvm only, easy to lose sight of it). The one way to fix this compatibly is to get upstream qemu accept ':' in IDs.

Still I'm not lectured about the evils of ':' in IDs... :-(

Quoted 9 lines

If we're fine with incompatible change here, or upstream qemu forces the incompatible change on us by refusing to accept ':', then I think we should simply drop the fallback.

We could continue to fall back to strings that pass id_wellformed(). Don't like it.

Without the fallback, there is no use of name left. Your patch creates a new one: use it instead of qdev ID in messages. Why is that useful?

I think "[domain:]B:D.F" is enough good standard format to point a PCI device. At least it is used for "host=". I don't know why it is not acceptable for use as ID.

And I imagined that someone will feel uneasy if outputs start to have no B:D.F in it... But there could be other approach, like adding B:D.F as prefix for output of assigned devices, no matter id/name is present or not.

I don't know why name have invented here... but I guess there should be a reason because there it is. I'll wait someone who can tell it.

As far as I can tell, "name" predates the qdev conversion, and was used just for error messages and such.

It defaulted to "host". When Gerd
did the qdev conversion, he made "id" default to "name", then "host". See commit 6b5bbd04.

Defaulting "id" that way was probably not such a good idea. We generally don't make up qdev IDs, because that risks collision with user-specified IDs.

Since we've broken compatibility already, I figure we could just as well stop defaulting "id" to "host". When we need to identify the device to the user, use "id" if it exists, else its PCI address.