Re: [Qemu-devel] [PATCH v7 4/8] ACPI: Add Virtual Machine Generation ID support

[Ben Warren]

> On Feb 16, 2017, at 1:56 AM, Igor Mammedov <address@hidden> wrote:
> 
> On Wed, 15 Feb 2017 22:18:14 -0800
> address@hidden wrote:
> 
>> From: Ben Warren <address@hidden>
>> 
>> This implements the VM Generation ID feature by passing a 128-bit
>> GUID to the guest via a fw_cfg blob.
>> Any time the GUID changes, an ACPI notify event is sent to the guest
>> 
>> The user interface is a simple device with one parameter:
>> - guid (string, must be "auto" or in UUID format
>>   xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
>> 
>> Signed-off-by: Ben Warren <address@hidden>
> Reviewed-by: Igor Mammedov <address@hidden>
> 
> Thing to get fixed on top is to check
> that there isn't vmgenid device present already
> into realizefn() and fail gracefully is there is.
> 
I made the change as follows:
===

diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c
index c8465df..fa3de6d 100644
--- a/hw/acpi/vmgenid.c
+++ b/hw/acpi/vmgenid.c
@@ -207,8 +207,15 @@ static void vmgenid_handle_reset(void *opaque)
 
 static void vmgenid_realize(DeviceState *dev, Error **errp)
 {
+    static bool is_realized = false;
     VmGenIdState *vms = VMGENID(dev);
+
+    if (is_realized) {
+        error_setg(errp, "Device %s may only be specified once",
+                   VMGENID_DEVICE);
+    }
     qemu_register_reset(vmgenid_handle_reset, vms);
+    is_realized = true;
 }

===
Sample output:
$ ../workspace/qemu/x86_64-softmmu/qemu-system-x86_64 -nographic -bios 
../workspace/seabios/out/bios.bin -machine type=q35 -hda 
beiwe-with-vmgenid-driver.qcow2 -qmp unix:./qmp-sock,server,nowait -device 
vmgenid,guid="324e6eaf-d1d1-4bf6-bf41-b9bb6c91fb66" -device 
vmgenid,guid="324e6eaf-d1d1-4bf6-bf41-b9bb6c91fb67"
qemu-system-x86_64: -device vmgenid,guid=324e6eaf-d1d1-4bf6-bf41-b9bb6c91fb67: 
Device vmgenid may only be specified once


Good enough?  If so, I’ll roll it in.  Otherwise, it’ll be a supplemental patch.

—Ben

<snip>

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