[PATCH 4/7] drm/amdgpu/virt: add function to check MMIO accessing

[Deucher, Alexander]

> -----Original Message-----
> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf
> Of Pixel Ding
> Sent: Monday, October 23, 2017 6:03 AM
> To: amd-gfx at lists.freedesktop.org
> Cc: Sun, Gary; Ding, Pixel; Li, Bingley
> Subject: [PATCH 4/7] drm/amdgpu/virt: add function to check MMIO
> accessing
> 
> From: pding <Pixel.Ding at amd.com>
> 
> MMIO space can be blocked on virtualised device. Add this function
> to check if MMIO is blocked or not.
> 
> Todo: need a reliable method such like communation with hypervisor.
> 
> Signed-off-by: pding <Pixel.Ding at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c | 5 +++++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h | 1 +
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> index e97f80f..33dac7e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> @@ -24,6 +24,11 @@
>  #include "amdgpu.h"
>  #define MAX_KIQ_REG_WAIT	100000000 /* in usecs */
> 
> +bool amdgpu_virt_mmio_blocked(struct amdgpu_device *adev)
> +{
> +	return RREG32_NO_KIQ(0xc040) == 0xffffffff;
> +}

Is this safe?  Won't accessing non-instanced registers cause a problem?  Probably also worth commenting that register this is and a note for future asics in case the register map changes.

Alex

> +
>  int amdgpu_allocate_static_csa(struct amdgpu_device *adev)
>  {
>  	int r;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> index b89d37f..81efb9d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> @@ -276,6 +276,7 @@ static inline bool is_virtual_machine(void)
>  }
> 
>  struct amdgpu_vm;
> +bool amdgpu_virt_mmio_blocked(struct amdgpu_device *adev);
>  int amdgpu_allocate_static_csa(struct amdgpu_device *adev);
>  int amdgpu_map_static_csa(struct amdgpu_device *adev, struct
> amdgpu_vm *vm,
>  			  struct amdgpu_bo_va **bo_va);
> --
> 2.9.5
> 
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