Re: [Qemu-devel] Virtualbox svga card in KVM

Re: [Qemu-devel] Virtualbox svga card in KVM

[Alon Levy]

> 
> 
> Hi,
>      I am planning on bringing in the virtualbox svga card into kvm
>      as a new svga card type (vbox probably?) so that we can load
>      the VirtualBox SVGA card drivers in the guest.
> 
>      Is this even feasible?. Any ideas on where I should start
>      looking?

I don't see why it wouldn't, sounds like a great idea. You can look at hw/qxl.c, hw/cirrus_vga.c, hw/vmware_vga.c as existing pci vga cards. Also this should go on qemu-devel (cc'ed).

> 
> Regards,Sriram
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [Qemu-devel] Virtualbox svga card in KVM

[Sriram Murthy]

Hi,
    I am looking into hw/vga.c and hw/vga-pci.c as a starting point in my effort to get vbox svga card into kvm. 

    However, given my very basic understanding of VGA/SVGA standards, can somebody throw some light on the inner workings of the std vga card in kvm?
    Also, are there any good urls/blogs/standards that I must be aware of before starting on this porting effort?
    Any help here will be greatly appreciated.
Thanks and regards,
Sriram



----- Original Message -----
From: Alon Levy <alevy@redhat.com>
To: Sriram Murthy <sriramsm@yahoo.com>
Cc: kvm@vger.kernel.org; qemu list <qemu-devel@nongnu.org>
Sent: Thursday, March 21, 2013 7:53 AM
Subject: Re: Virtualbox svga card in KVM

> 
> 
> Hi,
>      I am planning on bringing in the virtualbox svga card into kvm
>      as a new svga card type (vbox probably?) so that we can load
>      the VirtualBox SVGA card drivers in the guest.
> 
>      Is this even feasible?. Any ideas on where I should start
>      looking?

I don't see why it wouldn't, sounds like a great idea. You can look at hw/qxl.c, hw/cirrus_vga.c, hw/vmware_vga.c as existing pci vga cards. Also this should go on qemu-devel (cc'ed).

> 
> Regards,Sriram
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [Qemu-devel] Virtualbox svga card in KVM

[Sriram Murthy]

Hi,
    I am looking into hw/vga.c and hw/vga-pci.c as a starting point in my effort to get vbox svga card into kvm. 

   
 However, given my very basic understanding of VGA/SVGA standards, can 
somebody throw some light on the inner workings of the std vga card in 
kvm?
    Also, are there any good urls/blogs/standards that I must be aware of before starting on this porting effort?
    Any help here will be greatly appreciated.
Thanks and regards,
Sriram


----- Original Message -----
From: Alon Levy <alevy@redhat.com>
To: Sriram Murthy <sriramsm@yahoo.com>
Cc: kvm@vger.kernel.org; qemu list <qemu-devel@nongnu.org>
Sent: Thursday, March 21, 2013 7:53 AM
Subject: Re: Virtualbox svga card in KVM

> 
> 
> Hi,
>      I am planning on bringing in the virtualbox svga card into kvm
>      as a new svga card type (vbox probably?) so that we can load
>      the VirtualBox SVGA card drivers in the guest.
> 
>      Is this even feasible?. Any ideas on where I should start
>      looking?

I don't see why it wouldn't, sounds like a great idea. You can look at hw/qxl.c, hw/cirrus_vga.c, hw/vmware_vga.c as existing pci vga cards. Also this should go on qemu-devel (cc'ed).

> 
> Regards,Sriram
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [Qemu-devel] Virtualbox svga card in KVM

[Stefan Hajnoczi]

On Thu, Mar 21, 2013 at 10:53:21AM -0400, Alon Levy wrote:
> >      I am planning on bringing in the virtualbox svga card into kvm
> >      as a new svga card type (vbox probably?) so that we can load
> >      the VirtualBox SVGA card drivers in the guest.

I'm curious if the vbox SVGA card has features that existing QEMU
graphics cards do not provide?

Stefan

Re: [Qemu-devel] Virtualbox svga card in KVM

[Sriram Murthy]

For starters, virtual box has better SVGA WDDM drivers that allows for a much richer display when the VM display is local.
I am yet to completely understand both the KVM and the virtualbox SVGA card (actually, the virtualbox SVGA card is based off of the KVM VGA card), so I may not be the authority here.
-Sriram



----- Original Message -----
From: Stefan Hajnoczi <stefanha@gmail.com>
To: Sriram Murthy <sriramsm@yahoo.com>
Cc: kvm@vger.kernel.org; qemu list <qemu-devel@nongnu.org>
Sent: Friday, April 5, 2013 12:06 AM
Subject: Re: Virtualbox svga card in KVM

On Thu, Mar 21, 2013 at 10:53:21AM -0400, Alon Levy wrote:
> >      I am planning on bringing in the virtualbox svga card into kvm
> >      as a new svga card type (vbox probably?) so that we can load
> >      the VirtualBox SVGA card drivers in the guest.

I'm curious if the vbox SVGA card has features that existing QEMU
graphics cards do not provide?

Stefan

Re: [Qemu-devel] Virtualbox svga card in KVM

[Stefan Hajnoczi]

On Fri, Apr 05, 2013 at 04:52:05PM -0700, Sriram Murthy wrote:
> For starters, virtual box has better SVGA WDDM drivers that allows for a much richer display when the VM display is local.

What does "much richer display" mean?

Stefan

Re: [Qemu-devel] Virtualbox svga card in KVM

[Sriram Murthy]

By "richer display", I meant support for different resolution and color depth (including support for nonstandard resolutions as well).
-Sriram




----- Original Message -----
From: Stefan Hajnoczi <stefanha@gmail.com>
To: Sriram Murthy <sriramsm@yahoo.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>; qemu list <qemu-devel@nongnu.org>
Sent: Monday, April 8, 2013 3:46 AM
Subject: Re: Virtualbox svga card in KVM

On Fri, Apr 05, 2013 at 04:52:05PM -0700, Sriram Murthy wrote:
> For starters, virtual box has better SVGA WDDM drivers that allows for a much richer display when the VM display is local.

What does "much richer display" mean?

Stefan

Re: [Qemu-devel] Virtualbox svga card in KVM

[Peter Maydell]

On 6 April 2013 00:52, Sriram Murthy <sriramsm@yahoo.com> wrote:
> (actually, the virtualbox SVGA card is based off of the KVM VGA card)

Is it possible to implement it as an extension to the VGA
card device, or has it diverged incompatibly such that it
has to be its own separate device model?

thanks
-- PMM

Re: [Qemu-devel] Virtualbox svga card in KVM

[Sriram Murthy]

The Virtualbox SVGA card was derived out of the KVM VGA card, so there are quite a few similarities (I am deliberately being vague here as I am still in the process of discovering the features of both these cards completely). Having said that, the APIs and the data structures themselves have been modified to add new features (like displaying a custom bmp as the VGA bootup logo) and it has a custom vga bios as well.
Also, it is better that it be its own separate device model, so that maintenance of the vbox code becomes easier later. Further, I am thinking on the lines of retaining the VIrtualbox SVGA card code as is, and write a small KVM abstraction layer, so that it will be easy to port the bug fixes into the vbox SVGA card later on. 
Any comments/suggestions welcome here.

-Sriram



----- Original Message -----
From: Peter Maydell <peter.maydell@linaro.org>
To: Sriram Murthy <sriramsm@yahoo.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>; qemu list <qemu-devel@nongnu.org>; "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Sent: Monday, April 8, 2013 8:11 AM
Subject: Re: [Qemu-devel] Virtualbox svga card in KVM

On 6 April 2013 00:52, Sriram Murthy <sriramsm@yahoo.com> wrote:
> (actually, the virtualbox SVGA card is based off of the KVM VGA card)

Is it possible to implement it as an extension to the VGA
card device, or has it diverged incompatibly such that it
has to be its own separate device model?

thanks
-- PMM

Re: [Qemu-devel] Virtualbox svga card in KVM

[Yan Vugenfirer]

On Apr 6, 2013, at 2:52 AM, Sriram Murthy wrote:

> For starters, virtual box has better SVGA WDDM drivers that allows for a much richer display when the VM display is local.
Does it support S3 and S4 with Windows 8?

Yan.

> I am yet to completely understand both the KVM and the virtualbox SVGA card (actually, the virtualbox SVGA card is based off of the KVM VGA card), so I may not be the authority here.
> -Sriram
> 
> 
> 
> ----- Original Message -----
> From: Stefan Hajnoczi <stefanha@gmail.com>
> To: Sriram Murthy <sriramsm@yahoo.com>
> Cc: kvm@vger.kernel.org; qemu list <qemu-devel@nongnu.org>
> Sent: Friday, April 5, 2013 12:06 AM
> Subject: Re: Virtualbox svga card in KVM
> 
> On Thu, Mar 21, 2013 at 10:53:21AM -0400, Alon Levy wrote:
>>>      I am planning on bringing in the virtualbox svga card into kvm
>>>      as a new svga card type (vbox probably?) so that we can load
>>>      the VirtualBox SVGA card drivers in the guest.
> 
> I'm curious if the vbox SVGA card has features that existing QEMU
> graphics cards do not provide?
> 
> Stefan
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [Qemu-devel] Virtualbox svga card in KVM

[Sriram Murthy]

No idea. I havent had a chance to install Windows 8 on Virtualbox yet.
-Sriram



----- Original Message -----
From: Yan Vugenfirer <yvugenfi@redhat.com>
To: Sriram Murthy <sriramsm@yahoo.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>; "kvm@vger.kernel.org" <kvm@vger.kernel.org>; qemu list <qemu-devel@nongnu.org>
Sent: Tuesday, April 9, 2013 9:04 AM
Subject: Re: Virtualbox svga card in KVM


On Apr 6, 2013, at 2:52 AM, Sriram Murthy wrote:

> For starters, virtual box has better SVGA WDDM drivers that allows for a much richer display when the VM display is local.
Does it support S3 and S4 with Windows 8?

Yan.

> I am yet to completely understand both the KVM and the virtualbox SVGA card (actually, the virtualbox SVGA card is based off of the KVM VGA card), so I may not be the authority here.
> -Sriram
> 
> 
> 
> ----- Original Message -----
> From: Stefan Hajnoczi <stefanha@gmail.com>
> To: Sriram Murthy <sriramsm@yahoo.com>
> Cc: kvm@vger.kernel.org; qemu list <qemu-devel@nongnu.org>
> Sent: Friday, April 5, 2013 12:06 AM
> Subject: Re: Virtualbox svga card in KVM
> 
> On Thu, Mar 21, 2013 at 10:53:21AM -0400, Alon Levy wrote:
>>>      I am planning on bringing in the virtualbox svga card into kvm
>>>      as a new svga card type (vbox probably?) so that we can load
>>>      the VirtualBox SVGA card drivers in the guest.
> 
> I'm curious if the vbox SVGA card has features that existing QEMU
> graphics cards do not provide?
> 
> Stefan
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [Qemu-devel] Virtualbox svga card in KVM

[Andreas Färber]

Hi,

Am 08.04.2013 18:05, schrieb Sriram Murthy:
> The Virtualbox SVGA card was derived out of the KVM VGA card, so there are quite a few similarities (I am deliberately being vague here as I am still in the process of discovering the features of both these cards completely). Having said that, the APIs and the data structures themselves have been modified to add new features (like displaying a custom bmp as the VGA bootup logo) and it has a custom vga bios as well.
> Also, it is better that it be its own separate device model, so that maintenance of the vbox code becomes easier later. Further, I am thinking on the lines of retaining the VIrtualbox SVGA card code as is, and write a small KVM abstraction layer, so that it will be easy to port the bug fixes into the vbox SVGA card later on. 
> Any comments/suggestions welcome here.

Personally, I think that the connection between VirtualBox and QEMU is
very unidirectional if there is any... So code-wise our focus should
rather be to avoid code copies/divergence within our tree and to share
code with existing in-tree devices, especially if you are not paid to
continuously take care of this device once accepted into QEMU - that's
how I interpret PMM's question below.

There is nothing generally wrong with using KVM for guest driver
development or to make existing stripped-down guest images work at all
by adding such a special device.

However, proposing to adopt a random vendor's paravirtual graphics card
just because it has a few more resolutions and drivers on a particular
platform does not strike me as a big advantage over SPICE, VMware VGA or
past virtio-vga/-fb standardization attempts.

Regards,
Andreas

> 
> -Sriram
> 
> 
> 
> ----- Original Message -----
> From: Peter Maydell <peter.maydell@linaro.org>
> To: Sriram Murthy <sriramsm@yahoo.com>
> Cc: Stefan Hajnoczi <stefanha@gmail.com>; qemu list <qemu-devel@nongnu.org>; "kvm@vger.kernel.org" <kvm@vger.kernel.org>
> Sent: Monday, April 8, 2013 8:11 AM
> Subject: Re: [Qemu-devel] Virtualbox svga card in KVM
> 
> On 6 April 2013 00:52, Sriram Murthy <sriramsm@yahoo.com> wrote:
>> (actually, the virtualbox SVGA card is based off of the KVM VGA card)
> 
> Is it possible to implement it as an extension to the VGA
> card device, or has it diverged incompatibly such that it
> has to be its own separate device model?
> 
> thanks
> -- PMM

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg

Re: [Qemu-devel] Virtualbox svga card in KVM

[Sriram Murthy]

Hi,


>Personally, I think that the connection between VirtualBox and QEMU is
>very unidirectional if there is any... So code-wise our focus should
>rather be to avoid code copies/divergence within our tree and to share
>code with existing in-tree devices, especially if you are not paid to
>continuously take care of this device once accepted into QEMU - that's
>how I interpret PMM's question below.

>There is nothing generally wrong with using KVM for guest driver
>development or to make existing stripped-down guest images work at all
>by adding such a special device.

>However, proposing to adopt a random vendor's paravirtual graphics card
>just because it has a few more resolutions and drivers on a particular
>platform does not strike me as a big advantage over SPICE, VMware VGA or
>past virtio-vga/-fb standardization attempts.

Well, this idea came to me after I tried to use an OpenGL program that I wrote in Win7 running on KVM with a local SDL display interface. 
The experience was so bad, and to give it a shot, I ran it on VirtualBox, with the same guest image (but with VirtualBox WDDM drivers) and there was a night and day difference in experience.
Also, frankly, IMHO, adding a new card to KVM (regardless of the features it brings to the table) will only provide more choices for the end KVM user!.

-Sriram

> 
> -Sriram
> 
> 
> 
> ----- Original Message -----
> From: Peter Maydell <peter.maydell@linaro.org>
> To: Sriram Murthy <sriramsm@yahoo.com>
> Cc: Stefan Hajnoczi <stefanha@gmail.com>; qemu list <qemu-devel@nongnu.org>; "kvm@vger.kernel.org" <kvm@vger.kernel.org>
> Sent: Monday, April 8, 2013 8:11 AM
> Subject: Re: [Qemu-devel] Virtualbox svga card in KVM
> 
> On 6 April 2013 00:52, Sriram Murthy <sriramsm@yahoo.com> wrote:
>> (actually, the virtualbox SVGA card is based off of the KVM VGA card)
> 
> Is it possible to implement it as an extension to the VGA
> card device, or has it diverged incompatibly such that it
> has to be its own separate device model?
> 
> thanks
> -- PMM

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg

Re: [Qemu-devel] Virtualbox svga card in KVM

[Stefan Hajnoczi]

On Tue, Apr 09, 2013 at 11:25:05AM -0700, Sriram Murthy wrote:
> 
> 
> Hi,
> 
> 
> >Personally, I think that the connection between VirtualBox and QEMU is
> >very unidirectional if there is any... So code-wise our focus should
> >rather be to avoid code copies/divergence within our tree and to share
> >code with existing in-tree devices, especially if you are not paid to
> >continuously take care of this device once accepted into QEMU - that's
> >how I interpret PMM's question below.
> 
> >There is nothing generally wrong with using KVM for guest driver
> >development or to make existing stripped-down guest images work at all
> >by adding such a special device.
> 
> >However, proposing to adopt a random vendor's paravirtual graphics card
> >just because it has a few more resolutions and drivers on a particular
> >platform does not strike me as a big advantage over SPICE, VMware VGA or
> >past virtio-vga/-fb standardization attempts.
> 
> Well, this idea came to me after I tried to use an OpenGL program that I wrote in Win7 running on KVM with a local SDL display interface. 
> The experience was so bad, and to give it a shot, I ran it on VirtualBox, with the same guest image (but with VirtualBox WDDM drivers) and there was a night and day difference in experience.
> Also, frankly, IMHO, adding a new card to KVM (regardless of the features it brings to the table) will only provide more choices for the end KVM user!.

It's even better to improve the existing stuff because adding new stuff
often creates partially overlapping but different feature sets.  Then
users need to learn about and decide which option is right for them.

Given your mention of OpenGL I guess the problem isn't just that a few
display modes are missing.

Please share what you find as you dig more into the vbox vga code so we
can learn what specific pieces are missing in QEMU.

Stefan

Re: [Qemu-devel] Virtualbox svga card in KVM

[Gerd Hoffmann]

On 04/08/13 17:11, Peter Maydell wrote:
> On 6 April 2013 00:52, Sriram Murthy <sriramsm@yahoo.com> wrote:
>> (actually, the virtualbox SVGA card is based off of the KVM VGA card)
> 
> Is it possible to implement it as an extension to the VGA
> card device, or has it diverged incompatibly such that it
> has to be its own separate device model?

Not needed.  One just has to go write a windows driver.  The virtual
hardware can handle any resolution just fine.

cheers,
  Gerd

Re: [Qemu-devel] Virtualbox svga card in KVM

[Sriram Murthy]

[-- Attachment #1: Type: text/plain, Size: 1498 bytes --]

Some updates on this - 
I changed the PCI Device ID and Vendor ID in hw/vga.c, and was able to get the VirtualBox SVGA card driver installed in WinXP running on KVM.
However, when I try to change the resolution, KVM crashes with a SIGFPE in vbe_ioport_write_data(), and this is due to line_offset being zero in this statement - 

      h = s->vram_size / line_offset 
Also, I am seeing that the line_offset is computed by reading the vbe_regs. So, is it that the driver in  the guest is programming the vbe regs?. 

What should be the line_offset value, if the desired resolution is 800x600?
Regards,
Sriram

 



________________________________
 From: Gerd Hoffmann <kraxel@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org> 
Cc: Sriram Murthy <sriramsm@yahoo.com>; Stefan Hajnoczi <stefanha@gmail.com>; qemu list <qemu-devel@nongnu.org>; "kvm@vger.kernel.org" <kvm@vger.kernel.org> 
Sent: Monday, April 15, 2013 5:26 AM
Subject: Re: [Qemu-devel] Virtualbox svga card in KVM
 

On 04/08/13 17:11, Peter Maydell wrote:
> On 6 April 2013 00:52, Sriram Murthy <sriramsm@yahoo.com> wrote:
>> (actually, the virtualbox SVGA card is based off of the KVM VGA card)
> 
> Is it possible to implement it as an extension to the VGA
> card device, or has it diverged incompatibly such that it
> has to be its own separate device model?

Not needed.  One just has to go write a windows driver.  The virtual
hardware can handle any resolution just fine.

cheers,
  Gerd

[-- Attachment #2: Type: text/html, Size: 3743 bytes --]

Re: [Qemu-devel] Virtualbox svga card in KVM

[Gerd Hoffmann]

On 04/18/13 18:58, Sriram Murthy wrote:
> Some updates on this - I changed the PCI Device ID and Vendor ID in
> hw/vga.c, and was able to get the VirtualBox SVGA card driver
> installed in WinXP running on KVM. However, when I try to change the
> resolution, KVM crashes with a SIGFPE in vbe_ioport_write_data(), and
> this is due to line_offset being zero in this statement -
> 
> h = s->vram_size / line_offset Also, I am seeing that the line_offset
> is computed by reading the vbe_regs. So, is it that the driver in
> the guest is programming the vbe regs?.

Seems so, it crashes in a code path which actually writes to one of the
vbe regs.

> What should be the line_offset value, if the desired resolution is
> 800x600? Regards, Sriram

Depends on the desired depth.  The guest didn't set the depth register
though, thats why qemu is crashing ...

Maybe virtualbox uses another register layout.

cheers,
  Gerd

Re: [Qemu-devel] Virtualbox svga card in KVM

[Veruca Salt]

----------------------------------------
> Date: Mon, 15 Apr 2013 14:26:25 +0200
> From: kraxel@redhat.com
> To: peter.maydell@linaro.org
> CC: sriramsm@yahoo.com; stefanha@gmail.com; qemu-devel@nongnu.org; kvm@vger.kernel.org
> Subject: Re: [Qemu-devel] Virtualbox svga card in KVM
>
> On 04/08/13 17:11, Peter Maydell wrote:
> > On 6 April 2013 00:52, Sriram Murthy <sriramsm@yahoo.com> wrote:
> >> (actually, the virtualbox SVGA card is based off of the KVM VGA card)
> >
> > Is it possible to implement it as an extension to the VGA
> > card device, or has it diverged incompatibly such that it
> > has to be its own separate device model?
>
> Not needed. One just has to go write a windows driver. The virtual
> hardware can handle any resolution just fine.
>
> cheers,
> Gerd
>

Time for a mea culpa; as a user I have extended my research. The KVM vga
 sdl combination is around native speed when tested on a like-for-like 
basis with intel igp.
Which probably explains why evrybody else is happy. :)
What we may have to do is fix up a gpu with drivers. Somewhat non-trivial.
Any suggestions folks?
Regards,
Simon
ps-vbox gives us another 12% flat out.

> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
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