* [PATCH] radeon: Test for PCI root bus before assuming bus->self
@ 2014-08-27 19:01 Alex Williamson
2014-08-27 22:11 ` Alex Deucher
0 siblings, 1 reply; 5+ messages in thread
From: Alex Williamson @ 2014-08-27 19:01 UTC (permalink / raw)
To: alexander.deucher, christian.koenig, dri-devel
Cc: linux-kernel, airlied, alex.williamson
If we assign a Radeon device to a virtual machine, we can no longer
assume a fixed hardware topology, like the GPU having a parent device.
This patch simply adds a few pci_is_root_bus() tests to avoid passing
a NULL pointer to PCI access functions, allowing the radeon driver to
work in a QEMU 440FX machine with an assigned HD8570 on the emulated
PCI root bus.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
drivers/gpu/drm/radeon/cik.c | 6 +++++-
drivers/gpu/drm/radeon/si.c | 6 +++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index 79a5a55..cc34308 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -9555,6 +9555,9 @@ static void cik_pcie_gen3_enable(struct radeon_device *rdev)
int ret, i;
u16 tmp16;
+ if (pci_is_root_bus(rdev->pdev->bus))
+ return;
+
if (radeon_pcie_gen2 == 0)
return;
@@ -9781,7 +9784,8 @@ static void cik_program_aspm(struct radeon_device *rdev)
if (orig != data)
WREG32_PCIE_PORT(PCIE_LC_LINK_WIDTH_CNTL, data);
- if (!disable_clkreq) {
+ if (!disable_clkreq &&
+ !pci_is_root_bus(rdev->pdev->bus)) {
struct pci_dev *root = rdev->pdev->bus->self;
u32 lnkcap;
diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index a1274a3..ffb1d4e 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -7177,6 +7177,9 @@ static void si_pcie_gen3_enable(struct radeon_device *rdev)
int ret, i;
u16 tmp16;
+ if (pci_is_root_bus(rdev->pdev->bus))
+ return;
+
if (radeon_pcie_gen2 == 0)
return;
@@ -7454,7 +7457,8 @@ static void si_program_aspm(struct radeon_device *rdev)
if (orig != data)
WREG32_PIF_PHY1(PB1_PIF_CNTL, data);
- if (!disable_clkreq) {
+ if (!disable_clkreq &&
+ !pci_is_root_bus(rdev->pdev->bus)) {
struct pci_dev *root = rdev->pdev->bus->self;
u32 lnkcap;
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] radeon: Test for PCI root bus before assuming bus->self
2014-08-27 19:01 [PATCH] radeon: Test for PCI root bus before assuming bus->self Alex Williamson
@ 2014-08-27 22:11 ` Alex Deucher
2014-08-28 1:32 ` Dave Airlie
0 siblings, 1 reply; 5+ messages in thread
From: Alex Deucher @ 2014-08-27 22:11 UTC (permalink / raw)
To: Alex Williamson
Cc: Deucher, Alexander, Christian Koenig, Maling list - DRI developers, LKML
On Wed, Aug 27, 2014 at 3:01 PM, Alex Williamson
<alex.williamson@redhat.com> wrote:
> If we assign a Radeon device to a virtual machine, we can no longer
> assume a fixed hardware topology, like the GPU having a parent device.
> This patch simply adds a few pci_is_root_bus() tests to avoid passing
> a NULL pointer to PCI access functions, allowing the radeon driver to
> work in a QEMU 440FX machine with an assigned HD8570 on the emulated
> PCI root bus.
>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Added to my -fixes queue. thanks!
Alex
> ---
>
> drivers/gpu/drm/radeon/cik.c | 6 +++++-
> drivers/gpu/drm/radeon/si.c | 6 +++++-
> 2 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
> index 79a5a55..cc34308 100644
> --- a/drivers/gpu/drm/radeon/cik.c
> +++ b/drivers/gpu/drm/radeon/cik.c
> @@ -9555,6 +9555,9 @@ static void cik_pcie_gen3_enable(struct radeon_device *rdev)
> int ret, i;
> u16 tmp16;
>
> + if (pci_is_root_bus(rdev->pdev->bus))
> + return;
> +
> if (radeon_pcie_gen2 == 0)
> return;
>
> @@ -9781,7 +9784,8 @@ static void cik_program_aspm(struct radeon_device *rdev)
> if (orig != data)
> WREG32_PCIE_PORT(PCIE_LC_LINK_WIDTH_CNTL, data);
>
> - if (!disable_clkreq) {
> + if (!disable_clkreq &&
> + !pci_is_root_bus(rdev->pdev->bus)) {
> struct pci_dev *root = rdev->pdev->bus->self;
> u32 lnkcap;
>
> diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
> index a1274a3..ffb1d4e 100644
> --- a/drivers/gpu/drm/radeon/si.c
> +++ b/drivers/gpu/drm/radeon/si.c
> @@ -7177,6 +7177,9 @@ static void si_pcie_gen3_enable(struct radeon_device *rdev)
> int ret, i;
> u16 tmp16;
>
> + if (pci_is_root_bus(rdev->pdev->bus))
> + return;
> +
> if (radeon_pcie_gen2 == 0)
> return;
>
> @@ -7454,7 +7457,8 @@ static void si_program_aspm(struct radeon_device *rdev)
> if (orig != data)
> WREG32_PIF_PHY1(PB1_PIF_CNTL, data);
>
> - if (!disable_clkreq) {
> + if (!disable_clkreq &&
> + !pci_is_root_bus(rdev->pdev->bus)) {
> struct pci_dev *root = rdev->pdev->bus->self;
> u32 lnkcap;
>
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] radeon: Test for PCI root bus before assuming bus->self
2014-08-27 22:11 ` Alex Deucher
@ 2014-08-28 1:32 ` Dave Airlie
2014-08-28 2:09 ` Alex Williamson
2014-08-28 2:18 ` Alex Deucher
0 siblings, 2 replies; 5+ messages in thread
From: Dave Airlie @ 2014-08-28 1:32 UTC (permalink / raw)
To: Alex Deucher
Cc: Alex Williamson, Deucher, Alexander, Christian Koenig,
Maling list - DRI developers, LKML
> On Wed, Aug 27, 2014 at 3:01 PM, Alex Williamson
> <alex.williamson@redhat.com> wrote:
>> If we assign a Radeon device to a virtual machine, we can no longer
>> assume a fixed hardware topology, like the GPU having a parent device.
>> This patch simply adds a few pci_is_root_bus() tests to avoid passing
>> a NULL pointer to PCI access functions, allowing the radeon driver to
>> work in a QEMU 440FX machine with an assigned HD8570 on the emulated
>> PCI root bus.
>>
>> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
>
Does this mean inside a VM we can't enable pcie 2 speeds?
This could lead to a quite disappointing speed decrease for DMA transfers.
Dave.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] radeon: Test for PCI root bus before assuming bus->self
2014-08-28 1:32 ` Dave Airlie
@ 2014-08-28 2:09 ` Alex Williamson
2014-08-28 2:18 ` Alex Deucher
1 sibling, 0 replies; 5+ messages in thread
From: Alex Williamson @ 2014-08-28 2:09 UTC (permalink / raw)
To: Dave Airlie
Cc: Alex Deucher, Deucher, Alexander, Christian Koenig,
Maling list - DRI developers, LKML
On Thu, 2014-08-28 at 11:32 +1000, Dave Airlie wrote:
> > On Wed, Aug 27, 2014 at 3:01 PM, Alex Williamson
> > <alex.williamson@redhat.com> wrote:
> >> If we assign a Radeon device to a virtual machine, we can no longer
> >> assume a fixed hardware topology, like the GPU having a parent device.
> >> This patch simply adds a few pci_is_root_bus() tests to avoid passing
> >> a NULL pointer to PCI access functions, allowing the radeon driver to
> >> work in a QEMU 440FX machine with an assigned HD8570 on the emulated
> >> PCI root bus.
> >>
> >> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> >
>
> Does this mean inside a VM we can't enable pcie 2 speeds?
Shouldn't the device already be set to something reasonable before it's
assigned?
> This could lead to a quite disappointing speed decrease for DMA transfers.
We couldn't do it before anyway, there's no decrease. Even with a Q35
QEMU chipset the best we were doing was tweaking dummy registers on the
upstream port. Should VFIO be doing bus tuning prior to exposing the
device? I suppose our other option would be to let the link control
bits of the emulated downstream port pass through to the host. In any
case, I don't see that this patch limits performance any more than it
already is for a VM. Thanks,
Alex
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] radeon: Test for PCI root bus before assuming bus->self
2014-08-28 1:32 ` Dave Airlie
2014-08-28 2:09 ` Alex Williamson
@ 2014-08-28 2:18 ` Alex Deucher
1 sibling, 0 replies; 5+ messages in thread
From: Alex Deucher @ 2014-08-28 2:18 UTC (permalink / raw)
To: Dave Airlie
Cc: Alex Williamson, Deucher, Alexander, Christian Koenig,
Maling list - DRI developers, LKML
On Wed, Aug 27, 2014 at 9:32 PM, Dave Airlie <airlied@gmail.com> wrote:
>> On Wed, Aug 27, 2014 at 3:01 PM, Alex Williamson
>> <alex.williamson@redhat.com> wrote:
>>> If we assign a Radeon device to a virtual machine, we can no longer
>>> assume a fixed hardware topology, like the GPU having a parent device.
>>> This patch simply adds a few pci_is_root_bus() tests to avoid passing
>>> a NULL pointer to PCI access functions, allowing the radeon driver to
>>> work in a QEMU 440FX machine with an assigned HD8570 on the emulated
>>> PCI root bus.
>>>
>>> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
>>
>
> Does this mean inside a VM we can't enable pcie 2 speeds?
>
> This could lead to a quite disappointing speed decrease for DMA transfers.
It depends on the sbios, but most boards negotiate the highest speed at boot.
Alex
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-08-28 2:18 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2014-08-27 19:01 [PATCH] radeon: Test for PCI root bus before assuming bus->self Alex Williamson
2014-08-27 22:11 ` Alex Deucher
2014-08-28 1:32 ` Dave Airlie
2014-08-28 2:09 ` Alex Williamson
2014-08-28 2:18 ` Alex Deucher
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