linux-kernel - Re: [PATCHv3 2/2] drm/amdgpu: Register MCE notifier for Aldebaran RAS

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Date:   Thu, 23 Sep 2021 14:29:07 +0000
From:   Yazen Ghannam <yazen.ghannam@....com>
To:     Mukul Joshi <mukul.joshi@....com>
Cc:     linux-edac@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, bp@...en8.de, mingo@...hat.com,
        mchehab@...nel.org, amd-gfx@...ts.freedesktop.org
Subject: Re: [PATCHv3 2/2] drm/amdgpu: Register MCE notifier for Aldebaran RAS

On Wed, Sep 22, 2021 at 03:36:20PM -0400, Mukul Joshi wrote:
> On Aldebaran, GPU driver will handle bad page retirement
> even though UMC is host managed. As a result, register a
> bad page retirement handler on the mce notifier chain to
> retire bad pages on Aldebaran.
> 

I think this should state that the driver will do page retirement for
GPU-managed memory. As written, it implies that the driver do page retirement
in general for the system.

...

> +
> +static int amdgpu_bad_page_notifier(struct notifier_block *nb,
> +				    unsigned long val, void *data)
> +{
> +	struct mce *m = (struct mce *)data;
> +	struct amdgpu_device *adev = NULL;
> +	uint32_t gpu_id = 0;
> +	uint32_t umc_inst = 0;
> +	uint32_t ch_inst, channel_index = 0;
> +	struct ras_err_data err_data = {0, 0, 0, NULL};
> +	struct eeprom_table_record err_rec;
> +	uint64_t retired_page;
> +
> +	/*
> +	 * If the error was generated in UMC_V2, which belongs to GPU UMCs,
> +	 * and error occurred in DramECC (Extended error code = 0) then only
> +	 * process the error, else bail out.
> +	 */
> +	if (!m || !((smca_get_bank_type(m->bank) == SMCA_UMC_V2) &&
> +		    (XEC(m->status, 0x1f) == 0x0)))

The MCA_STATUS[ErrorCodeExt] field is bits [21:16], so the mask should be
0x3f.

> +		return NOTIFY_DONE;
> +
> +	/*
> +	 * If it is correctable error, return.
> +	 */
> +	if (mce_is_correctable(m))
> +		return NOTIFY_OK;

Shouldn't this be "NOTIFY_DONE" if "don't care" about this error?

Thanks,
Yazen