Re: [PATCH v7 07/11] iommu/vt-d: Add nested translation helper function

[Lu Baolu <baolu.lu@linux.intel.com>]

Hi,

On 10/25/19 3:55 AM, Jacob Pan wrote:
> Nested translation mode is supported in VT-d 3.0 Spec.CH 3.8.
> With PASID granular translation type set to 0x11b, translation
> result from the first level(FL) also subject to a second level(SL)
> page table translation. This mode is used for SVA virtualization,
> where FL performs guest virtual to guest physical translation and
> SL performs guest physical to host physical translation.
> 
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com>
> ---
>   drivers/iommu/intel-pasid.c | 207 ++++++++++++++++++++++++++++++++++++++++++++
>   drivers/iommu/intel-pasid.h |  12 +++
>   2 files changed, 219 insertions(+)
> 
> diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
> index ffbd416ed3b8..f846a907cfcf 100644
> --- a/drivers/iommu/intel-pasid.c
> +++ b/drivers/iommu/intel-pasid.c
> @@ -415,6 +415,76 @@ pasid_set_flpm(struct pasid_entry *pe, u64 value)
>   	pasid_set_bits(&pe->val[2], GENMASK_ULL(3, 2), value << 2);
>   }
>   
> +/*
> + * Setup the Extended Memory Type(EMT) field (Bits 91-93)
> + * of a scalable mode PASID entry.
> + */
> +static inline void
> +pasid_set_emt(struct pasid_entry *pe, u64 value)
> +{
> +	pasid_set_bits(&pe->val[1], GENMASK_ULL(29, 27), value << 27);
> +}
> +
> +/*
> + * Setup the Page Attribute Table (PAT) field (Bits 96-127)
> + * of a scalable mode PASID entry.
> + */
> +static inline void
> +pasid_set_pat(struct pasid_entry *pe, u64 value)
> +{
> +	pasid_set_bits(&pe->val[1], GENMASK_ULL(63, 32), value << 27);

Should be "value << 32", right?

> +}
> +
> +/*
> + * Setup the Cache Disable (CD) field (Bit 89)
> + * of a scalable mode PASID entry.
> + */
> +static inline void
> +pasid_set_cd(struct pasid_entry *pe)
> +{
> +	pasid_set_bits(&pe->val[1], 1 << 25, 1);
> +}
> +
> +/*
> + * Setup the Extended Memory Type Enable (EMTE) field (Bit 90)
> + * of a scalable mode PASID entry.
> + */
> +static inline void
> +pasid_set_emte(struct pasid_entry *pe)
> +{
> +	pasid_set_bits(&pe->val[1], 1 << 26, 1);
> +}
> +
> +/*
> + * Setup the Extended Access Flag Enable (EAFE) field (Bit 135)
> + * of a scalable mode PASID entry.
> + */
> +static inline void
> +pasid_set_eafe(struct pasid_entry *pe)
> +{
> +	pasid_set_bits(&pe->val[2], 1 << 7, 1);
> +}
> +
> +/*
> + * Setup the Page-level Cache Disable (PCD) field (Bit 95)
> + * of a scalable mode PASID entry.
> + */
> +static inline void
> +pasid_set_pcd(struct pasid_entry *pe)
> +{
> +	pasid_set_bits(&pe->val[1], 1 << 31, 1);
> +}
> +
> +/*
> + * Setup the Page-level Write-Through (PWT)) field (Bit 94)
> + * of a scalable mode PASID entry.
> + */
> +static inline void
> +pasid_set_pwt(struct pasid_entry *pe)
> +{
> +	pasid_set_bits(&pe->val[1], 1 << 30, 1);
> +}
> +
>   static void
>   pasid_cache_invalidation_with_pasid(struct intel_iommu *iommu,
>   				    u16 did, int pasid)
> @@ -647,3 +717,140 @@ int intel_pasid_setup_pass_through(struct intel_iommu *iommu,
>   
>   	return 0;
>   }
> +
> +static int intel_pasid_setup_bind_data(struct intel_iommu *iommu,
> +				struct pasid_entry *pte,
> +				struct iommu_gpasid_bind_data_vtd *pasid_data)
> +{
> +	/*
> +	 * Not all guest PASID table entry fields are passed down during bind,
> +	 * here we only set up the ones that are dependent on guest settings.
> +	 * Execution related bits such as NXE, SMEP are not meaningful to IOMMU,
> +	 * therefore not set. Other fields, such as snoop related, are set based
> +	 * on host needs regardless of  guest settings.
> +	 */
> +	if (pasid_data->flags & IOMMU_SVA_VTD_GPASID_SRE) {
> +		if (!ecap_srs(iommu->ecap)) {
> +			pr_err("No supervisor request support on %s\n",
> +			       iommu->name);
> +			return -EINVAL;
> +		}
> +		pasid_set_sre(pte);
> +	}
> +
> +	if ((pasid_data->flags & IOMMU_SVA_VTD_GPASID_EAFE) && ecap_eafs(iommu->ecap))
> +		pasid_set_eafe(pte);
> +
> +	if (pasid_data->flags & IOMMU_SVA_VTD_GPASID_EMTE) {
> +		pasid_set_emte(pte);
> +		pasid_set_emt(pte, pasid_data->emt);
> +	}
> +
> +	/*
> +	 * Memory type is only applicable to devices inside processor coherent
> +	 * domain. PCIe devices are not included. We can skip the rest of the
> +	 * flags if IOMMU does not support MTS.
> +	 */
> +	if (!ecap_mts(iommu->ecap)) {
> +		pr_info("%s does not support memory type bind guest PASID\n",
> +			iommu->name);
> +		return 0;
> +	}

How about making below lines as

if (ecap_mts(iommu->ecap)) {
	do various pasid entry settings
} else {
	pr_info(...);
}

Otherwise, when someone later adds code at the end of this function. It
might be ignored by above return 0.

Best regards,
baolu

> +
> +	if (pasid_data->flags & IOMMU_SVA_VTD_GPASID_PCD)
> +		pasid_set_pcd(pte);
> +	if (pasid_data->flags & IOMMU_SVA_VTD_GPASID_PWT)
> +		pasid_set_pwt(pte);
> +	if (pasid_data->flags & IOMMU_SVA_VTD_GPASID_CD)
> +		pasid_set_cd(pte);
> +	pasid_set_pat(pte, pasid_data->pat);
> +
> +	return 0;
> +
> +}
> +
> +/**
> + * intel_pasid_setup_nested() - Set up PASID entry for nested translation
> + * which is used for vSVA. The first level page tables are used for
> + * GVA-GPA translation in the guest, second level page tables are used
> + * for GPA to HPA translation.
> + *
> + * @iommu:      Iommu which the device belong to
> + * @dev:        Device to be set up for translation
> + * @gpgd:       FLPTPTR: First Level Page translation pointer in GPA
> + * @pasid:      PASID to be programmed in the device PASID table
> + * @pasid_data: Additional PASID info from the guest bind request
> + * @domain:     Domain info for setting up second level page tables
> + * @addr_width: Address width of the first level (guest)
> + */
> +int intel_pasid_setup_nested(struct intel_iommu *iommu,
> +			struct device *dev, pgd_t *gpgd,
> +			int pasid, struct iommu_gpasid_bind_data_vtd *pasid_data,
> +			struct dmar_domain *domain,
> +			int addr_width)
> +{
> +	struct pasid_entry *pte;
> +	struct dma_pte *pgd;
> +	u64 pgd_val;
> +	int agaw;
> +	u16 did;
> +
> +	if (!ecap_nest(iommu->ecap)) {
> +		pr_err("IOMMU: %s: No nested translation support\n",
> +		       iommu->name);
> +		return -EINVAL;
> +	}
> +
> +	pte = intel_pasid_get_entry(dev, pasid);
> +	if (WARN_ON(!pte))
> +		return -EINVAL;
> +
> +	pasid_clear_entry(pte);
> +
> +	/* Sanity checking performed by caller to make sure address
> +	 * width matching in two dimensions:
> +	 * 1. CPU vs. IOMMU
> +	 * 2. Guest vs. Host.
> +	 */
> +	switch (addr_width) {
> +	case 57:
> +		pasid_set_flpm(pte, 1);
> +		break;
> +	case 48:
> +		pasid_set_flpm(pte, 0);
> +		break;
> +	default:
> +		dev_err(dev, "Invalid paging mode %d\n", addr_width);
> +		return -EINVAL;
> +	}
> +
> +	pasid_set_flptr(pte, (u64)gpgd);
> +
> +	intel_pasid_setup_bind_data(iommu, pte, pasid_data);
> +
> +	/* Setup the second level based on the given domain */
> +	pgd = domain->pgd;
> +
> +	for (agaw = domain->agaw; agaw != iommu->agaw; agaw--) {
> +		pgd = phys_to_virt(dma_pte_addr(pgd));
> +		if (!dma_pte_present(pgd)) {
> +			dev_err(dev, "Invalid domain page table\n");
> +			return -EINVAL;
> +		}
> +	}
> +	pgd_val = virt_to_phys(pgd);
> +	pasid_set_slptr(pte, pgd_val);
> +	pasid_set_fault_enable(pte);
> +
> +	did = domain->iommu_did[iommu->seq_id];
> +	pasid_set_domain_id(pte, did);
> +
> +	pasid_set_address_width(pte, agaw);
> +	pasid_set_page_snoop(pte, !!ecap_smpwc(iommu->ecap));
> +
> +	pasid_set_translation_type(pte, PASID_ENTRY_PGTT_NESTED);
> +	pasid_set_present(pte);
> +	pasid_flush_caches(iommu, pte, pasid, did);
> +
> +	return 0;
> +}
> diff --git a/drivers/iommu/intel-pasid.h b/drivers/iommu/intel-pasid.h
> index e413e884e685..09c85db73b77 100644
> --- a/drivers/iommu/intel-pasid.h
> +++ b/drivers/iommu/intel-pasid.h
> @@ -46,6 +46,7 @@
>    * to vmalloc or even module mappings.
>    */
>   #define PASID_FLAG_SUPERVISOR_MODE	BIT(0)
> +#define PASID_FLAG_NESTED		BIT(1)
>   
>   struct pasid_dir_entry {
>   	u64 val;
> @@ -55,6 +56,11 @@ struct pasid_entry {
>   	u64 val[8];
>   };
>   
> +#define PASID_ENTRY_PGTT_FL_ONLY	(1)
> +#define PASID_ENTRY_PGTT_SL_ONLY	(2)
> +#define PASID_ENTRY_PGTT_NESTED		(3)
> +#define PASID_ENTRY_PGTT_PT		(4)
> +
>   /* The representative of a PASID table */
>   struct pasid_table {
>   	void			*table;		/* pasid table pointer */
> @@ -103,6 +109,12 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
>   int intel_pasid_setup_pass_through(struct intel_iommu *iommu,
>   				   struct dmar_domain *domain,
>   				   struct device *dev, int pasid);
> +int intel_pasid_setup_nested(struct intel_iommu *iommu,
> +			struct device *dev, pgd_t *pgd,
> +			int pasid,
> +			struct iommu_gpasid_bind_data_vtd *pasid_data,
> +			struct dmar_domain *domain,
> +			int addr_width);
>   void intel_pasid_tear_down_entry(struct intel_iommu *iommu,
>   				 struct device *dev, int pasid);
>   int vcmd_alloc_pasid(struct intel_iommu *iommu, unsigned int *pasid);
>