Drivers: hv: vmbus: Add VMbus IMC device to unsupported list

Hyper-V may offer an Initial Machine Configuration (IMC) synthetic
device to guest VMs. The device may be used by Windows guests to get
specialization information, such as the hostname.  But the device
is not used in Linux and there is no Linux driver, so it is
unsupported.

Currently, the IMC device GUID is not recognized by the VMbus driver,
which results in an "Unknown GUID" error message during boot. Add
the GUID to the list of known but unsupported devices so that the
error message is not generated. Other than avoiding the error message,
there is no change in guest behavior.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1649818140-100953-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

drivers/hv/channel_mgmt.c

@@ -152,6 +152,7 @@ static const struct {
 	{ HV_AVMA1_GUID },
 	{ HV_AVMA2_GUID },
 	{ HV_RDV_GUID	},
+	{ HV_IMC_GUID	},
 };
 
 /*

include/linux/hyperv.h

@@ -1451,12 +1451,14 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size);
 			  0x80, 0x2e, 0x27, 0xed, 0xe1, 0x9f)
 
 /*
- * Linux doesn't support the 3 devices: the first two are for
- * Automatic Virtual Machine Activation, and the third is for
- * Remote Desktop Virtualization.
+ * Linux doesn't support these 4 devices: the first two are for
+ * Automatic Virtual Machine Activation, the third is for
+ * Remote Desktop Virtualization, and the fourth is Initial
+ * Machine Configuration (IMC) used only by Windows guests.
  * {f8e65716-3cb3-4a06-9a60-1889c5cccab5}
  * {3375baf4-9e15-4b30-b765-67acb10d607b}
  * {276aacf4-ac15-426c-98dd-7521ad3f01fe}
+ * {c376c1c3-d276-48d2-90a9-c04748072c60}
  */
 
 #define HV_AVMA1_GUID \
@@ -1471,6 +1473,10 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size);
 	.guid = GUID_INIT(0x276aacf4, 0xac15, 0x426c, 0x98, 0xdd, \
 			  0x75, 0x21, 0xad, 0x3f, 0x01, 0xfe)
 
+#define HV_IMC_GUID \
+	.guid = GUID_INIT(0xc376c1c3, 0xd276, 0x48d2, 0x90, 0xa9, \
+			  0xc0, 0x47, 0x48, 0x07, 0x2c, 0x60)
+
 /*
  * Common header for Hyper-V ICs
  */