[PATCH 2/2] drm/amdgpu: disable vm fault irq during prt accessed

[Christian König]

NAK, the problem is not the interrupt.

E.g. causing faults by accessing unmapped pages with the SDMA can still 
crash the MC.

The key point is that SDMA can't work with PRT tiles on pre-gmc9 and we 
need to forbid access on the application side.

Regards,
Christian.

Am 03.01.19 um 09:54 schrieb Chunming Zhou:
> For pre-gmc9, UMD can only access unmapped PRT tile from CB/TC without
> firing VM fault. Kernel would still receive the VM fault interrupt
> and output the error message if SDMA is the mc_client.
> GMC9 don't need the same since it handle the PRT in different way.
> We cannot just skip message for SDMA, as Christian pointed, VM fault
> could crash mc block, so we disable vm fault irq during prt range is
> accesed.
> The nagative is normal vm fault could be ignored during that peroid
> without enabling vm_debug kernel parameter.
>
> Change-Id: Ic3c62393768eca90e3e45eaf81e7f26f2e91de84
> Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c | 6 ++++++
>   drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 6 ++++++
>   drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 6 ++++++
>   3 files changed, 18 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
> index dae73f6768c2..175c4b319559 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
> @@ -486,6 +486,10 @@ static void gmc_v6_0_set_prt(struct amdgpu_device *adev, bool enable)
>   		WREG32(mmVM_PRT_APERTURE1_HIGH_ADDR, high);
>   		WREG32(mmVM_PRT_APERTURE2_HIGH_ADDR, high);
>   		WREG32(mmVM_PRT_APERTURE3_HIGH_ADDR, high);
> +		/* Note: when vm_debug enabled, vm fault from SDMAx accessing
> +		 * PRT range is normal. */
> +		if (!amdgpu_vm_debug)
> +			amdgpu_irq_put(adev, &adev->gmc.vm_fault, 0);
>   	} else {
>   		WREG32(mmVM_PRT_APERTURE0_LOW_ADDR, 0xfffffff);
>   		WREG32(mmVM_PRT_APERTURE1_LOW_ADDR, 0xfffffff);
> @@ -495,6 +499,8 @@ static void gmc_v6_0_set_prt(struct amdgpu_device *adev, bool enable)
>   		WREG32(mmVM_PRT_APERTURE1_HIGH_ADDR, 0x0);
>   		WREG32(mmVM_PRT_APERTURE2_HIGH_ADDR, 0x0);
>   		WREG32(mmVM_PRT_APERTURE3_HIGH_ADDR, 0x0);
> +		if (!amdgpu_vm_debug)
> +			amdgpu_irq_get(adev, &adev->gmc.vm_fault, 0);
>   	}
>   }
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> index 5bdeb358bfb5..a4d6d219f4e8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> @@ -582,6 +582,10 @@ static void gmc_v7_0_set_prt(struct amdgpu_device *adev, bool enable)
>   		WREG32(mmVM_PRT_APERTURE1_HIGH_ADDR, high);
>   		WREG32(mmVM_PRT_APERTURE2_HIGH_ADDR, high);
>   		WREG32(mmVM_PRT_APERTURE3_HIGH_ADDR, high);
> +		/* Note: when vm_debug enabled, vm fault from SDMAx accessing
> +		 * PRT range is normal. */
> +		if (!amdgpu_vm_debug)
> +			amdgpu_irq_put(adev, &adev->gmc.vm_fault, 0);
>   	} else {
>   		WREG32(mmVM_PRT_APERTURE0_LOW_ADDR, 0xfffffff);
>   		WREG32(mmVM_PRT_APERTURE1_LOW_ADDR, 0xfffffff);
> @@ -591,6 +595,8 @@ static void gmc_v7_0_set_prt(struct amdgpu_device *adev, bool enable)
>   		WREG32(mmVM_PRT_APERTURE1_HIGH_ADDR, 0x0);
>   		WREG32(mmVM_PRT_APERTURE2_HIGH_ADDR, 0x0);
>   		WREG32(mmVM_PRT_APERTURE3_HIGH_ADDR, 0x0);
> +		if (!amdgpu_vm_debug)
> +			amdgpu_irq_get(adev, &adev->gmc.vm_fault, 0);
>   	}
>   }
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> index 5150ab614eaa..eea2eb7fc2f5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> @@ -808,6 +808,10 @@ static void gmc_v8_0_set_prt(struct amdgpu_device *adev, bool enable)
>   		WREG32(mmVM_PRT_APERTURE1_HIGH_ADDR, high);
>   		WREG32(mmVM_PRT_APERTURE2_HIGH_ADDR, high);
>   		WREG32(mmVM_PRT_APERTURE3_HIGH_ADDR, high);
> +		/* Note: when vm_debug enabled, vm fault from SDMAx accessing
> +		 * PRT range is normal. */
> +		if (!amdgpu_vm_debug)
> +			amdgpu_irq_put(adev, &adev->gmc.vm_fault, 0);
>   	} else {
>   		WREG32(mmVM_PRT_APERTURE0_LOW_ADDR, 0xfffffff);
>   		WREG32(mmVM_PRT_APERTURE1_LOW_ADDR, 0xfffffff);
> @@ -817,6 +821,8 @@ static void gmc_v8_0_set_prt(struct amdgpu_device *adev, bool enable)
>   		WREG32(mmVM_PRT_APERTURE1_HIGH_ADDR, 0x0);
>   		WREG32(mmVM_PRT_APERTURE2_HIGH_ADDR, 0x0);
>   		WREG32(mmVM_PRT_APERTURE3_HIGH_ADDR, 0x0);
> +		if (!amdgpu_vm_debug)
> +			amdgpu_irq_get(adev, &adev->gmc.vm_fault, 0);
>   	}
>   }
>