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

[Lazar, Lijo]

[AMD Official Use Only - AMD Internal Distribution Only]

Never mind, bit 16 and above is probably because of dword aligned offset.

Any reason not to do this in kiq/rlc based writes to normalise all?

Thanks,
Lijo
________________________________
From: Lazar, Lijo
Sent: Friday, June 14, 2024 5:20:30 PM
To: Jian, Jane <Jane.Jian at amd.com>; Chang, HaiJun <HaiJun.Chang at amd.com>; Zhao, Victor <Victor.Zhao at amd.com>
Cc: amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>
Subject: Re: [PATCH] drm/amdgpu: keep init xcc0 for all xccs under sriov



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 at amd.com>
> ---
>  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;
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