Patchwork [v3] pciinit: Enable default VGA device

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Submitter Alex Williamson
Date March 20, 2013, 4:58 p.m.
Message ID <20130320165728.22281.10294.stgit@bling.home>
Download mbox | patch
Permalink /patch/229434/
State New
Headers show

Comments

Alex Williamson - March 20, 2013, 4:58 p.m.
As QEMU gains PCI bridge and PCIe root port support, we won't always
find the VGA device on the root bus.  We therefore need to add support
to find and enable a VGA device and the path to it through the VGA
Enable support in the PCI bridge control register.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

v3: use pci_config_maskw() to trim out some code
v2: move to qemu specific pciinit.c

 src/optionroms.c |    2 +-
 src/pciinit.c    |   40 ++++++++++++++++++++++++++++++++++++++++
 src/util.h       |    1 +
 3 files changed, 42 insertions(+), 1 deletion(-)
Paul Menzel - March 20, 2013, 6:05 p.m.
Dear Alex,


Am Mittwoch, den 20.03.2013, 10:58 -0600 schrieb Alex Williamson:
> As QEMU gains PCI bridge and PCIe root port support,

could you give a commit or version for QEMU please.

> we won't always find the VGA device on the root bus.  We therefore
> need to add support to find and enable a VGA device and the path to it
> through the VGA Enable support in the PCI bridge control register.

Just to be sure, did you test this with older QEMU too?

> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> 
> v3: use pci_config_maskw() to trim out some code
> v2: move to qemu specific pciinit.c
> 
>  src/optionroms.c |    2 +-
>  src/pciinit.c    |   40 ++++++++++++++++++++++++++++++++++++++++
>  src/util.h       |    1 +
>  3 files changed, 42 insertions(+), 1 deletion(-)
> 
> diff --git a/src/optionroms.c b/src/optionroms.c
> index caa2151..ac92613 100644
> --- a/src/optionroms.c
> +++ b/src/optionroms.c
> @@ -213,7 +213,7 @@ run_file_roms(const char *prefix, int isvga, u64 *sources)
>   ****************************************************************/
>  
>  // Verify device is a vga device with legacy address decoding enabled.
> -static int
> +int
>  is_pci_vga(struct pci_device *pci)
>  {
>      if (pci->class != PCI_CLASS_DISPLAY_VGA)
> diff --git a/src/pciinit.c b/src/pciinit.c
> index ce0a4cc..bb9355f 100644
> --- a/src/pciinit.c
> +++ b/src/pciinit.c
> @@ -316,6 +316,44 @@ static void pci_bios_init_devices(void)
>      }
>  }
>  
> +static void pci_enable_default_vga(void)
> +{
> +    struct pci_device *pci;
> +
> +    foreachpci(pci) {
> +        if (is_pci_vga(pci)) {
> +            dprintf(1, "PCI: Using %02x:%02x.%x for primary VGA\n",
> +                    pci_bdf_to_bus(pci->bdf), pci_bdf_to_dev(pci->bdf),
> +                    pci_bdf_to_fn(pci->bdf));

As this is used several times, a function returning a string with %02x:%
02x.%x would be handy.

> +            return;
> +        }
> +    }

[…]

Acked-by: Paul Menzel <paulepanter@users.sourceforge.net>


Thahks,

Paul
Alex Williamson - March 20, 2013, 6:18 p.m.
On Wed, 2013-03-20 at 19:05 +0100, Paul Menzel wrote:
> Dear Alex,
> 
> 
> Am Mittwoch, den 20.03.2013, 10:58 -0600 schrieb Alex Williamson:
> > As QEMU gains PCI bridge and PCIe root port support,
> 
> could you give a commit or version for QEMU please.

This would be targeted towards QEMU 1.5.  Michael recently sent a pull
request with this patch to enable VGA routing in bridges:

https://git.kernel.org/cgit/virt/kvm/mst/qemu.git/commit/?h=pci&id=e475aeac3e2e7f6632c3ea7e83f4431c0ba3a467

It's difficult to make use of without an assigned VGA device, which I
plan to start posting soon.

> > we won't always find the VGA device on the root bus.  We therefore
> > need to add support to find and enable a VGA device and the path to it
> > through the VGA Enable support in the PCI bridge control register.
> 
> Just to be sure, did you test this with older QEMU too?

Yes, it works with the QEMU 1.2.x shipped in F18.  Any existing QEMU
configuration is going to have the VGA device on the host bridge and
therefore bail out on the first loop, having done nothing other than add
a debug print.

> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> > ---
> > 
> > v3: use pci_config_maskw() to trim out some code
> > v2: move to qemu specific pciinit.c
> > 
> >  src/optionroms.c |    2 +-
> >  src/pciinit.c    |   40 ++++++++++++++++++++++++++++++++++++++++
> >  src/util.h       |    1 +
> >  3 files changed, 42 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/optionroms.c b/src/optionroms.c
> > index caa2151..ac92613 100644
> > --- a/src/optionroms.c
> > +++ b/src/optionroms.c
> > @@ -213,7 +213,7 @@ run_file_roms(const char *prefix, int isvga, u64 *sources)
> >   ****************************************************************/
> >  
> >  // Verify device is a vga device with legacy address decoding enabled.
> > -static int
> > +int
> >  is_pci_vga(struct pci_device *pci)
> >  {
> >      if (pci->class != PCI_CLASS_DISPLAY_VGA)
> > diff --git a/src/pciinit.c b/src/pciinit.c
> > index ce0a4cc..bb9355f 100644
> > --- a/src/pciinit.c
> > +++ b/src/pciinit.c
> > @@ -316,6 +316,44 @@ static void pci_bios_init_devices(void)
> >      }
> >  }
> >  
> > +static void pci_enable_default_vga(void)
> > +{
> > +    struct pci_device *pci;
> > +
> > +    foreachpci(pci) {
> > +        if (is_pci_vga(pci)) {
> > +            dprintf(1, "PCI: Using %02x:%02x.%x for primary VGA\n",
> > +                    pci_bdf_to_bus(pci->bdf), pci_bdf_to_dev(pci->bdf),
> > +                    pci_bdf_to_fn(pci->bdf));
> 
> As this is used several times, a function returning a string with %02x:%
> 02x.%x would be handy.
> 
> > +            return;
> > +        }
> > +    }
> 
> […]
> 
> Acked-by: Paul Menzel <paulepanter@users.sourceforge.net>

Thanks!

Alex
Gerd Hoffmann - March 21, 2013, 6:49 a.m.
On 03/20/13 17:58, Alex Williamson wrote:
> As QEMU gains PCI bridge and PCIe root port support, we won't always
> find the VGA device on the root bus.  We therefore need to add support
> to find and enable a VGA device and the path to it through the VGA
> Enable support in the PCI bridge control register.
> 
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Looks good to me.

cheers,
  Gerd
Kevin O'Connor - March 23, 2013, 12:50 a.m.
On Wed, Mar 20, 2013 at 10:58:47AM -0600, Alex Williamson wrote:
> As QEMU gains PCI bridge and PCIe root port support, we won't always
> find the VGA device on the root bus.  We therefore need to add support
> to find and enable a VGA device and the path to it through the VGA
> Enable support in the PCI bridge control register.
> 
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Thanks.  I pushed this change.

-Kevin

Patch

diff --git a/src/optionroms.c b/src/optionroms.c
index caa2151..ac92613 100644
--- a/src/optionroms.c
+++ b/src/optionroms.c
@@ -213,7 +213,7 @@  run_file_roms(const char *prefix, int isvga, u64 *sources)
  ****************************************************************/
 
 // Verify device is a vga device with legacy address decoding enabled.
-static int
+int
 is_pci_vga(struct pci_device *pci)
 {
     if (pci->class != PCI_CLASS_DISPLAY_VGA)
diff --git a/src/pciinit.c b/src/pciinit.c
index ce0a4cc..bb9355f 100644
--- a/src/pciinit.c
+++ b/src/pciinit.c
@@ -316,6 +316,44 @@  static void pci_bios_init_devices(void)
     }
 }
 
+static void pci_enable_default_vga(void)
+{
+    struct pci_device *pci;
+
+    foreachpci(pci) {
+        if (is_pci_vga(pci)) {
+            dprintf(1, "PCI: Using %02x:%02x.%x for primary VGA\n",
+                    pci_bdf_to_bus(pci->bdf), pci_bdf_to_dev(pci->bdf),
+                    pci_bdf_to_fn(pci->bdf));
+            return;
+        }
+    }
+
+    pci = pci_find_class(PCI_CLASS_DISPLAY_VGA);
+    if (!pci) {
+        dprintf(1, "PCI: No VGA devices found\n");
+        return;
+    }
+
+    dprintf(1, "PCI: Enabling %02x:%02x.%x for primary VGA\n",
+            pci_bdf_to_bus(pci->bdf), pci_bdf_to_dev(pci->bdf),
+            pci_bdf_to_fn(pci->bdf));
+
+    pci_config_maskw(pci->bdf, PCI_COMMAND, 0,
+                     PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
+
+    while (pci->parent) {
+        pci = pci->parent;
+
+        dprintf(1, "PCI: Setting VGA enable on bridge %02x:%02x.%x\n",
+                pci_bdf_to_bus(pci->bdf), pci_bdf_to_dev(pci->bdf),
+                pci_bdf_to_fn(pci->bdf));
+
+        pci_config_maskw(pci->bdf, PCI_BRIDGE_CONTROL, 0, PCI_BRIDGE_CTL_VGA);
+        pci_config_maskw(pci->bdf, PCI_COMMAND, 0,
+                         PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
+    }
+}
 
 /****************************************************************
  * Platform device initialization
@@ -804,4 +842,6 @@  pci_setup(void)
     pci_bios_init_devices();
 
     free(busses);
+
+    pci_enable_default_vga();
 }
diff --git a/src/util.h b/src/util.h
index af029fc..99aff78 100644
--- a/src/util.h
+++ b/src/util.h
@@ -344,6 +344,7 @@  void vgahook_setup(struct pci_device *pci);
 
 // optionroms.c
 void call_bcv(u16 seg, u16 ip);
+int is_pci_vga(struct pci_device *pci);
 void optionrom_setup(void);
 void vgarom_setup(void);
 void s3_resume_vga(void);