linux-kernel - Re: [PATCH v7 02/12] iommu/arm-smmu-v3: Remove unrecoverable faults reporting

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Message-ID: <4593a682-b33b-4284-b94c-7f7fd9351171@intel.com>
Date:   Mon, 4 Dec 2023 18:54:47 +0800
From:   Yi Liu <yi.l.liu@...el.com>
To:     Lu Baolu <baolu.lu@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>,
        "Will Deacon" <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        "Jason Gunthorpe" <jgg@...pe.ca>,
        Kevin Tian <kevin.tian@...el.com>,
        "Jean-Philippe Brucker" <jean-philippe@...aro.org>,
        Nicolin Chen <nicolinc@...dia.com>
CC:     Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Yan Zhao <yan.y.zhao@...el.com>, <iommu@...ts.linux.dev>,
        <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 02/12] iommu/arm-smmu-v3: Remove unrecoverable faults
 reporting



On 2023/11/15 11:02, Lu Baolu wrote:
> No device driver registers fault handler to handle the reported
> unrecoveraable faults. Remove it to avoid dead code.

I noticed only ARM code is removed. So intel iommu driver does not have
code that tries to report unrecoveraable faults?

> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
> Reviewed-by: Kevin Tian <kevin.tian@...el.com>
> ---
>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 46 ++++++---------------
>   1 file changed, 13 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 7445454c2af2..505400538a2e 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -1463,7 +1463,6 @@ arm_smmu_find_master(struct arm_smmu_device *smmu, u32 sid)
>   static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
>   {
>   	int ret;
> -	u32 reason;
>   	u32 perm = 0;
>   	struct arm_smmu_master *master;
>   	bool ssid_valid = evt[0] & EVTQ_0_SSV;
> @@ -1473,16 +1472,9 @@ static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
>   
>   	switch (FIELD_GET(EVTQ_0_ID, evt[0])) {
>   	case EVT_ID_TRANSLATION_FAULT:
> -		reason = IOMMU_FAULT_REASON_PTE_FETCH;
> -		break;
>   	case EVT_ID_ADDR_SIZE_FAULT:
> -		reason = IOMMU_FAULT_REASON_OOR_ADDRESS;
> -		break;
>   	case EVT_ID_ACCESS_FAULT:
> -		reason = IOMMU_FAULT_REASON_ACCESS;
> -		break;
>   	case EVT_ID_PERMISSION_FAULT:
> -		reason = IOMMU_FAULT_REASON_PERMISSION;
>   		break;
>   	default:
>   		return -EOPNOTSUPP;
> @@ -1492,6 +1484,9 @@ static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
>   	if (evt[1] & EVTQ_1_S2)
>   		return -EFAULT;
>   
> +	if (!(evt[1] & EVTQ_1_STALL))
> +		return -EOPNOTSUPP;
> +
>   	if (evt[1] & EVTQ_1_RnW)
>   		perm |= IOMMU_FAULT_PERM_READ;
>   	else
> @@ -1503,32 +1498,17 @@ static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
>   	if (evt[1] & EVTQ_1_PnU)
>   		perm |= IOMMU_FAULT_PERM_PRIV;
>   
> -	if (evt[1] & EVTQ_1_STALL) {
> -		flt->type = IOMMU_FAULT_PAGE_REQ;
> -		flt->prm = (struct iommu_fault_page_request) {
> -			.flags = IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE,
> -			.grpid = FIELD_GET(EVTQ_1_STAG, evt[1]),
> -			.perm = perm,
> -			.addr = FIELD_GET(EVTQ_2_ADDR, evt[2]),
> -		};
> +	flt->type = IOMMU_FAULT_PAGE_REQ;
> +	flt->prm = (struct iommu_fault_page_request) {
> +		.flags = IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE,
> +		.grpid = FIELD_GET(EVTQ_1_STAG, evt[1]),
> +		.perm = perm,
> +		.addr = FIELD_GET(EVTQ_2_ADDR, evt[2]),
> +	};
>   
> -		if (ssid_valid) {
> -			flt->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
> -			flt->prm.pasid = FIELD_GET(EVTQ_0_SSID, evt[0]);
> -		}
> -	} else {
> -		flt->type = IOMMU_FAULT_DMA_UNRECOV;
> -		flt->event = (struct iommu_fault_unrecoverable) {
> -			.reason = reason,
> -			.flags = IOMMU_FAULT_UNRECOV_ADDR_VALID,
> -			.perm = perm,
> -			.addr = FIELD_GET(EVTQ_2_ADDR, evt[2]),
> -		};
> -
> -		if (ssid_valid) {
> -			flt->event.flags |= IOMMU_FAULT_UNRECOV_PASID_VALID;
> -			flt->event.pasid = FIELD_GET(EVTQ_0_SSID, evt[0]);
> -		}
> +	if (ssid_valid) {
> +		flt->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
> +		flt->prm.pasid = FIELD_GET(EVTQ_0_SSID, evt[0]);
>   	}
>   
>   	mutex_lock(&smmu->streams_mutex);

-- 
Regards,
Yi Liu