QEMU

Bug #1119281
Comment #2

Comment 2 for bug 1119281

Revision history for this message

Stefan Hajnoczi (stefanha) wrote on 2013-02-11: Re: [Qemu-devel] [Bug 1119281] [NEW] The virtio network device breaks UuidCreateSequential()

On Fri, Feb 08, 2013 at 10:45:03AM -0000, Francois Gouget wrote:
> Public bug reported:
>
> UuidCreateSequential() usually creates version 1 UUIDs (1) which means
> they contain the main network card's MAC address. However when using a
> virtio network card and driver the UUIDs contain random data instead of
> the guest's MAC address. Changing the network card to either the default
> rtl8139 one or the e1000 one fixes the issue.

CCing Yan and Vadim, who work on the virtio-win drivers.

>
> Here is the software I have tested this with:
> * qemu 1.1.2+dfsg-5 and 1.4.0~rc0+dfsg-1exp (from Debian Testing and Experimental respectively)
> * The 0.1-49 and 0.1-52 Windows virtio drivers from https://alt.fedoraproject.org/pub/alt/virtio-win/latest/images/bin/
> * Both a 32-bit Windows XP guest and a 64-bit Windows 7 one.
>
>
> Here is how to test for this issue:
> * Set up a Windows guest with a single network card(2), a virtio one and install the corresponding driver.
>
> * Boot the guest and copy the uuidtest.exe file (see attachement) to it
>
> * On the command line, type 'ipconfig /all'. Give you the correct
> network card's MAC address on a line like the one below:
>
> Physical Address. . . . . . . . . : 52-54-00-C7-0E-97
>
> * Run uuidtest.exe. It will show the VM returning a UUID with the wrong
> MAC address, and quite possibly even a multicast MAC address! (3). In
> the example below 'f75292c62787' should have been the MAC address. Note
> that on Windows XP UuidCreateSequential() returns RPC_S_UUID_LOCAL_ONLY
> for virtio cards but that on Windows 7 it returns 0.
>
> UuidCreateSequential() returned 0
> uuid={56e1ffe4-71d8-11e2-b1cc-f75292c62787}
> Got a version 1 UUID
> The UUID does not contain a non-multicast MAC address
>
> * Reboot and notice uuidtest.exe now reports a different value where the
> MAC address should be.
>
> * Shut down the VM and switch the network card to rtl8139, install the
> drivers, run uuidtest.exe and notice that the last group of digits
> finally contains the correct MAC address.
>
>
> (1) https://en.wikipedia.org/wiki/Globally_unique_identifier#Algorithm
> (2) Best do it with a single card to avoid confusion over which is the primary one.
> (3) If the first byte of the address is odd then this is a multicast address.
> https://en.wikipedia.org/wiki/MAC_address#Address_details
>
> ** Affects: qemu
> Importance: Undecided
> Status: New
>
> ** Attachment added: "Test executable and source"
> https://bugs.launchpad.net/bugs/1119281/+attachment/3520477/+files/uuidtest.tar.bz2

On Fri, Feb 08, 2013 at 10:45:03AM -0000, Francois Gouget wrote:
> Public bug reported:
> 
> UuidCreateSequential() usually creates version 1 UUIDs (1) which means
> they contain the main network card's MAC address. However when using a
> virtio network card and driver the UUIDs contain random data instead of
> the guest's MAC address. Changing the network card to either the default
> rtl8139 one or the e1000 one fixes the issue.

CCing Yan and Vadim, who work on the virtio-win drivers.

> 
> Here is the software I have tested this with:
>  * qemu 1.1.2+dfsg-5 and 1.4.0~rc0+dfsg-1exp (from Debian Testing and Experimental respectively)
>  * The 0.1-49 and 0.1-52 Windows virtio drivers from https://alt.fedoraproject.org/pub/alt/virtio-win/latest/images/bin/
>  * Both a 32-bit Windows XP guest and a 64-bit Windows 7 one.
> 
> 
> Here is how to test for this issue:
> * Set up a Windows guest with a single network card(2), a virtio one and install the corresponding driver.
> 
> * Boot the guest and copy the uuidtest.exe file (see attachement) to it
> 
> * On the command line, type 'ipconfig /all'. Give you the correct
> network card's MAC address on a line like the one below:
> 
>         Physical Address. . . . . . . . . : 52-54-00-C7-0E-97
> 
> * Run uuidtest.exe. It will show the VM returning a UUID with the wrong
> MAC address, and quite possibly even a multicast MAC address! (3). In
> the example below 'f75292c62787' should have been the MAC address. Note
> that on Windows XP UuidCreateSequential() returns RPC_S_UUID_LOCAL_ONLY
> for virtio cards but that on Windows 7 it returns 0.
> 
>         UuidCreateSequential() returned 0
>         uuid={56e1ffe4-71d8-11e2-b1cc-f75292c62787}
>         Got a version 1 UUID
>         The UUID does not contain a non-multicast MAC address
> 
> * Reboot and notice uuidtest.exe now reports a different value where the
> MAC address should be.
> 
> * Shut down the VM and switch the network card to rtl8139, install the
> drivers, run uuidtest.exe and notice that the last group of digits
> finally contains the correct MAC address.
> 
> 
> (1) https://en.wikipedia.org/wiki/Globally_unique_identifier#Algorithm
> (2) Best do it with a single card to avoid confusion over which is the primary one.
> (3) If the first byte of the address is odd then this is a multicast address.
>     https://en.wikipedia.org/wiki/MAC_address#Address_details
> 
> ** Affects: qemu
>      Importance: Undecided
>          Status: New
> 
> ** Attachment added: "Test executable and source"
>    https://bugs.launchpad.net/bugs/1119281/+attachment/3520477/+files/uuidtest.tar.bz2