Hi have a situation with a Windows 2003 server that uses a fax modem. I'd love to P2V this server but I need support for a Brooktrout faxmodem. The idea is, just pass anything to/from this hardware directly to the Windows guest VM, so the guest VM "thinks" it's connected to the faxmodem. I haven't run across anything that says I can do that with KVM virtual machines. Any ideas?
Thanks
- Greg Scott
On 06/15/2012 10:02 AM, Greg Scott wrote:
Hi have a situation with a Windows 2003 server that uses a fax modem. I'd love to P2V this server but I need support for a Brooktrout faxmodem. The idea is, just pass anything to/from this hardware directly to the Windows guest VM, so the guest VM "thinks" it's connected to the faxmodem. I haven't run across anything that says I can do that with KVM virtual machines. Any ideas?
With new enough hardware, or if you don't mind the security risks with older hardware where iommu was incomplete and could allow a malicious guest to take over the host, it is indeed possible with KVM to pass through raw PCI or USB host devices so that the host no longer touches the device, and the guest manipulates the device directly.
Are you using virsh, virt-manager, or some other means to manipulate your guest definition? Depending on that answer determines how you would add a host-device passthrough to your guest.
On Fri, 2012-06-15 at 10:38 -0600, Eric Blake wrote:
On 06/15/2012 10:02 AM, Greg Scott wrote:
Hi have a situation with a Windows 2003 server that uses a fax modem. I'd love to P2V this server but I need support for a Brooktrout faxmodem. The idea is, just pass anything to/from this hardware directly to the Windows guest VM, so the guest VM "thinks" it's connected to the faxmodem. I haven't run across anything that says I can do that with KVM virtual machines. Any ideas?
With new enough hardware, or if you don't mind the security risks with older hardware where iommu was incomplete and could allow a malicious guest to take over the host,
iommu is a requirement for PCI assignment, any partial support for iommu-less operation has been disabled as it never worked upstream and presented a security hole. Google guesses this is a PCI device, so you'll need a system with VT-d or AMD-Vi (if it's indeed a legacy PCI device vs a PCI-e device, it's often easier to make those work on VT-d). Thanks,
Alex
Ideally, I'd like to do this one with virt-manager on RHEL. Or Fedora. Maybe eventually on RHEV. If I do this, it would be new hardware - not sure if those Brooktrout modems are PCI-e or just PCI.
- Greg
-----Original Message----- From: Alex Williamson [mailto:alex.williamson@redhat.com] Sent: Friday, June 15, 2012 11:56 AM To: Eric Blake Cc: Greg Scott; virt@lists.fedoraproject.org Subject: Re: [fedora-virt] Support for modems and other such physical hardware?
On Fri, 2012-06-15 at 10:38 -0600, Eric Blake wrote:
On 06/15/2012 10:02 AM, Greg Scott wrote:
Hi have a situation with a Windows 2003 server that uses a fax modem. I'd love to P2V this server but I need support for a Brooktrout faxmodem. The idea is, just pass anything to/from this hardware directly to the Windows guest VM, so the guest VM "thinks" it's connected to the faxmodem. I haven't run across anything that says I can do that with KVM virtual machines. Any ideas?
With new enough hardware, or if you don't mind the security risks with older hardware where iommu was incomplete and could allow a malicious guest to take over the host,
iommu is a requirement for PCI assignment, any partial support for iommu-less operation has been disabled as it never worked upstream and presented a security hole. Google guesses this is a PCI device, so you'll need a system with VT-d or AMD-Vi (if it's indeed a legacy PCI device vs a PCI-e device, it's often easier to make those work on VT-d). Thanks,
Alex
Looking at virt-manager 0.8.6 on a RHEL test system here - it looks like I can modify a guest VM with virt-manager. Select the VM I want, go to the Information button, Add Hardware...PCI Host Device, and then select the device I want to associate with that VM. Looks straightforward enough - I wonder if the interface really means PCI or if it also works with PCI-e?
Has anyone done this with a Brooktrout faxmodem and Windows VM?
And again - if I do this, it will be on brand new hardware and everything today has the virtualization stuff these days.
Thanks
- Greg
-----Original Message----- From: virt-bounces@lists.fedoraproject.org [mailto:virt-bounces@lists.fedoraproject.org] On Behalf Of Greg Scott Sent: Friday, June 15, 2012 2:33 PM To: Alex Williamson; Eric Blake Cc: virt@lists.fedoraproject.org Subject: Re: [fedora-virt] Support for modems and other such physicalhardware?
Ideally, I'd like to do this one with virt-manager on RHEL. Or Fedora. Maybe eventually on RHEV. If I do this, it would be new hardware - not sure if those Brooktrout modems are PCI-e or just PCI.
- Greg
-----Original Message----- From: Alex Williamson [mailto:alex.williamson@redhat.com] Sent: Friday, June 15, 2012 11:56 AM To: Eric Blake Cc: Greg Scott; virt@lists.fedoraproject.org Subject: Re: [fedora-virt] Support for modems and other such physical hardware?
On Fri, 2012-06-15 at 10:38 -0600, Eric Blake wrote:
On 06/15/2012 10:02 AM, Greg Scott wrote:
Hi have a situation with a Windows 2003 server that uses a fax modem. I'd love to P2V this server but I need support for a Brooktrout faxmodem. The idea is, just pass anything to/from this hardware directly to the Windows guest VM, so the guest VM "thinks" it's connected to the faxmodem. I haven't run across anything that says I can do that with KVM virtual machines. Any ideas?
With new enough hardware, or if you don't mind the security risks with older hardware where iommu was incomplete and could allow a malicious guest to take over the host,
iommu is a requirement for PCI assignment, any partial support for iommu-less operation has been disabled as it never worked upstream and presented a security hole. Google guesses this is a PCI device, so you'll need a system with VT-d or AMD-Vi (if it's indeed a legacy PCI device vs a PCI-e device, it's often easier to make those work on VT-d). Thanks,
Alex
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On Fri, 2012-06-15 at 15:17 -0500, Greg Scott wrote:
Looking at virt-manager 0.8.6 on a RHEL test system here - it looks like I can modify a guest VM with virt-manager. Select the VM I want, go to the Information button, Add Hardware...PCI Host Device, and then select the device I want to associate with that VM. Looks straightforward enough - I wonder if the interface really means PCI or if it also works with PCI-e?
Yes, it supports both.
Has anyone done this with a Brooktrout faxmodem and Windows VM?
And again - if I do this, it will be on brand new hardware and everything today has the virtualization stuff these days.
CPU virtualization, yes. An IOMMU for device assignment, make sure you do your homework. It can be hard enough to figure out if the hardware supports it (ark.intel.com is your friend), then if it does, still make sure the vendor enables it. Both VT-d and AMD-Vi need BIOS support. If the device doesn't support MSI, shared interrupts can also be a nuisance. Thanks,
Alex
It can be hard enough to figure out if the hardware supports...
The hardware - meaning the Brooktrout modem itself or the host CPU? Reading up on the IOMMU, this looks like the same virtualization stuff that's been in all new Intel and AMD server CPUs for the past few years - am I on track? What is MSI? I suppose I could call Brooktrout - I'll bet they have a phone number.
- Greg
On Sat, 2012-06-16 at 09:56 -0500, Greg Scott wrote:
It can be hard enough to figure out if the hardware supports...
The hardware - meaning the Brooktrout modem itself or the host CPU?
The system chipset (but as the chipset often extends into the processors itself these days, sometimes the processor as well).
Reading up on the IOMMU, this looks like the same virtualization stuff that's been in all new Intel and AMD server CPUs for the past few years - am I on track?
If you're looking at server CPUs, possibly. On mainstream consumer CPUs it's hit an miss.
What is MSI?
Message signaled interrupts. sudo lspci -v -s <device> | grep MSI
I suppose I could call Brooktrout - I'll bet they have a phone number.
Good luck with that ;)
Alex
Yes, this will run on real, server class hardware if we do the project, so the IOMMU should not be an issue.
Thanks for the encouragement on contacting Brooktrout. :)
- Greg
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Alex Williamson -
Eric Blake -
Greg Scott