Re: [PATCH] drm/amdgpu: keep init xcc0 for all xccs under sriov

["Lazar, Lijo" <lijo.lazar@xxxxxxx>]

On 6/14/2024 4:40 PM, Jane Jian wrote:
> [WHY]
> sriov has the higher bit violation when flushing tlb
> 
> [HOW]
> for sriov only init XCC0(lower 16-bit) for all XCCs to avoid higher bit violation
> since kiq ring is always local, local address without XCC ID is enough to be sent to the XCC KIQ
> 

The description is incorrect.

Bits 18:20 represent xcc id. To guarantee all paths pass a local
address, you should just strip bits 18:20 in kiq/rlcg read/write
functions rather than here.

Thanks,
Lijo

> Signed-off-by: Jane Jian <Jane.Jian@xxxxxxx>
> ---
>  drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c | 23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c b/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c
> index e14acab5cceb..4e38a66a52f4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c
> @@ -537,29 +537,36 @@ static void gfxhub_v1_2_xcc_init(struct amdgpu_device *adev, uint32_t xcc_mask)
>  {
>  	struct amdgpu_vmhub *hub;
>  	int i;
> +	uint32_t gc_index;
>  
>  	for_each_inst(i, xcc_mask) {
>  		hub = &adev->vmhub[AMDGPU_GFXHUB(i)];
>  
> +		/* for sriov only init XCC0(lower 16-bit) to avoid higher bit violation */
> +		if (amdgpu_sriov_vf(adev))
> +			gc_index = 0;
> +		else
> +			gc_index = GET_INST(GC, i);
> +
>  		hub->ctx0_ptb_addr_lo32 =
> -			SOC15_REG_OFFSET(GC, GET_INST(GC, i),
> +			SOC15_REG_OFFSET(GC, gc_index,
>  				regVM_CONTEXT0_PAGE_TABLE_BASE_ADDR_LO32);
>  		hub->ctx0_ptb_addr_hi32 =
> -			SOC15_REG_OFFSET(GC, GET_INST(GC, i),
> +			SOC15_REG_OFFSET(GC, gc_index,
>  				regVM_CONTEXT0_PAGE_TABLE_BASE_ADDR_HI32);
>  		hub->vm_inv_eng0_sem =
> -			SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_INVALIDATE_ENG0_SEM);
> +			SOC15_REG_OFFSET(GC, gc_index, regVM_INVALIDATE_ENG0_SEM);
>  		hub->vm_inv_eng0_req =
> -			SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_INVALIDATE_ENG0_REQ);
> +			SOC15_REG_OFFSET(GC, gc_index, regVM_INVALIDATE_ENG0_REQ);
>  		hub->vm_inv_eng0_ack =
> -			SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_INVALIDATE_ENG0_ACK);
> +			SOC15_REG_OFFSET(GC, gc_index, regVM_INVALIDATE_ENG0_ACK);
>  		hub->vm_context0_cntl =
> -			SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_CONTEXT0_CNTL);
> +			SOC15_REG_OFFSET(GC, gc_index, regVM_CONTEXT0_CNTL);
>  		hub->vm_l2_pro_fault_status =
> -			SOC15_REG_OFFSET(GC, GET_INST(GC, i),
> +			SOC15_REG_OFFSET(GC, gc_index,
>  				regVM_L2_PROTECTION_FAULT_STATUS);
>  		hub->vm_l2_pro_fault_cntl =
> -			SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_L2_PROTECTION_FAULT_CNTL);
> +			SOC15_REG_OFFSET(GC, gc_index, regVM_L2_PROTECTION_FAULT_CNTL);
>  
>  		hub->ctx_distance = regVM_CONTEXT1_CNTL -
>  				regVM_CONTEXT0_CNTL;