diff mbox series

drm/amdgpu: do not use passthrough mode in Xen dom0

Message ID 20220426235718.1634359-1-marmarek@invisiblethingslab.com (mailing list archive)
State New, archived
Headers show
Series drm/amdgpu: do not use passthrough mode in Xen dom0 | expand

Commit Message

Marek Marczykowski-Górecki April 26, 2022, 11:57 p.m. UTC
While technically Xen dom0 is a virtual machine too, it does have
access to most of the hardware so it doesn't need to be considered a
"passthrough". Commit b818a5d37454 ("drm/amdgpu/gmc: use PCI BARs for
APUs in passthrough") changed how FB is accessed based on passthrough
mode. This breaks amdgpu in Xen dom0 with message like this:

    [drm:dc_dmub_srv_wait_idle [amdgpu]] *ERROR* Error waiting for DMUB idle: status=3

While the reason for this failure is unclear, the passthrough mode is
not really necessary in Xen dom0 anyway. So, to unbreak booting affected
kernels, disable passthrough mode in this case.

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1985
Fixes: b818a5d37454 ("drm/amdgpu/gmc: use PCI BARs for APUs in passthrough")
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Alex Deucher April 27, 2022, 2:47 p.m. UTC | #1
Applied.  Thanks!

Alex

On Wed, Apr 27, 2022 at 3:12 AM Marek Marczykowski-Górecki
<marmarek@invisiblethingslab.com> wrote:
>
> While technically Xen dom0 is a virtual machine too, it does have
> access to most of the hardware so it doesn't need to be considered a
> "passthrough". Commit b818a5d37454 ("drm/amdgpu/gmc: use PCI BARs for
> APUs in passthrough") changed how FB is accessed based on passthrough
> mode. This breaks amdgpu in Xen dom0 with message like this:
>
>     [drm:dc_dmub_srv_wait_idle [amdgpu]] *ERROR* Error waiting for DMUB idle: status=3
>
> While the reason for this failure is unclear, the passthrough mode is
> not really necessary in Xen dom0 anyway. So, to unbreak booting affected
> kernels, disable passthrough mode in this case.
>
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1985
> Fixes: b818a5d37454 ("drm/amdgpu/gmc: use PCI BARs for APUs in passthrough")
> Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> index a025f080aa6a..5e3756643da3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> @@ -24,6 +24,7 @@
>  #include <linux/module.h>
>
>  #include <drm/drm_drv.h>
> +#include <xen/xen.h>
>
>  #include "amdgpu.h"
>  #include "amdgpu_ras.h"
> @@ -710,7 +711,8 @@ void amdgpu_detect_virtualization(struct amdgpu_device *adev)
>                 adev->virt.caps |= AMDGPU_SRIOV_CAPS_ENABLE_IOV;
>
>         if (!reg) {
> -               if (is_virtual_machine())       /* passthrough mode exclus sriov mod */
> +               /* passthrough mode exclus sriov mod */
> +               if (is_virtual_machine() && !xen_initial_domain())
>                         adev->virt.caps |= AMDGPU_PASSTHROUGH_MODE;
>         }
>
> --
> 2.35.1
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
index a025f080aa6a..5e3756643da3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
@@ -24,6 +24,7 @@ 
 #include <linux/module.h>
 
 #include <drm/drm_drv.h>
+#include <xen/xen.h>
 
 #include "amdgpu.h"
 #include "amdgpu_ras.h"
@@ -710,7 +711,8 @@  void amdgpu_detect_virtualization(struct amdgpu_device *adev)
 		adev->virt.caps |= AMDGPU_SRIOV_CAPS_ENABLE_IOV;
 
 	if (!reg) {
-		if (is_virtual_machine())	/* passthrough mode exclus sriov mod */
+		/* passthrough mode exclus sriov mod */
+		if (is_virtual_machine() && !xen_initial_domain())
 			adev->virt.caps |= AMDGPU_PASSTHROUGH_MODE;
 	}