[PATCH 5/6] nvme: also return I/O command effects from nvme_command_effects

[Sagi Grimberg]

On 12/23/22 09:18, Christoph Hellwig wrote:
> To be able to use the Commands Supported and Effects Log for allowing
> unprivileged passtrough, it needs to be corretly reported for I/O
> commands as well.  Return the I/O command effects from
> nvme_command_effects, and also add a default list of effects for the
> NVM command set.  For other command sets, the Commands Supported and
> Effects log is required to be present already.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Reviewed-by: Kanchan Joshi <joshi.k at samsung.com>
> ---
>   drivers/nvme/host/core.c | 32 ++++++++++++++++++++++++++------
>   1 file changed, 26 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index e26b085a007aea..21d79c186d8c14 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -1074,6 +1074,18 @@ static u32 nvme_known_admin_effects(u8 opcode)
>   	return 0;
>   }
>   
> +static u32 nvme_known_nvm_effects(u8 opcode)
> +{
> +	switch (opcode) {
> +	case nvme_cmd_write:
> +	case nvme_cmd_write_zeroes:
> +	case nvme_cmd_write_uncor:
> +		 return NVME_CMD_EFFECTS_LBCC;
> +	default:
> +		return 0;
> +	}
> +}
> +
>   u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns, u8 opcode)
>   {
>   	u32 effects = 0;
> @@ -1081,16 +1093,24 @@ u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns, u8 opcode)
>   	if (ns) {
>   		if (ns->head->effects)
>   			effects = le32_to_cpu(ns->head->effects->iocs[opcode]);
> +		if (ns->head->ids.csi == NVME_CAP_CSS_NVM)
> +			effects |= nvme_known_nvm_effects(opcode);
>   		if (effects & ~(NVME_CMD_EFFECTS_CSUPP | NVME_CMD_EFFECTS_LBCC))
>   			dev_warn_once(ctrl->device,
> -				"IO command:%02x has unhandled effects:%08x\n",
> +				"IO command:%02x has unusual effects:%08x\n",
>   				opcode, effects);
> -		return 0;
> -	}
>   
> -	if (ctrl->effects)
> -		effects = le32_to_cpu(ctrl->effects->acs[opcode]);
> -	effects |= nvme_known_admin_effects(opcode);
> +		/*
> +		 * NVME_CMD_EFFECTS_CSE_MASK causes a freeze all I/O queues,
> +		 * which would deadlock when done on an I/O command.  Note that
> +		 * We already warn about an unusual effect above.
> +		 */

I think it would be helpful to warn that we are masking it out? The
warning above does not directly relate to the cse mask, but rather 
anthing outside of NVME_CMD_EFFECTS_CSUPP | NVME_CMD_EFFECTS_LBCC ?

> +		effects &= ~NVME_CMD_EFFECTS_CSE_MASK;
> +	} else {
> +		if (ctrl->effects)
> +			effects = le32_to_cpu(ctrl->effects->acs[opcode]);
> +		effects |= nvme_known_admin_effects(opcode);
> +	}
>   
>   	return effects;
>   }