Re: [PATCH v8 02/10] iommu/vt-d: Add nested translation helper function

Jacob Pan
2020-01-09T17:46:22Z

Hi Baolu,

Appreciate the review. Comments inline below.

On Wed, 18 Dec 2019 10:01:17 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:

> Hi Jacob,
>
> On 12/17/19 3:24 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 | 213
> > ++++++++++++++++++++++++++++++++++++++++++++
> > drivers/iommu/intel-pasid.h | 12 +++ include/linux/intel-iommu.h
> > | 3 + include/uapi/linux/iommu.h | 5 +-
> > 4 files changed, 232 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/intel-pasid.c
> > b/drivers/iommu/intel-pasid.c index 3cb569e76642..b178ad9e47ae
> > 100644 --- a/drivers/iommu/intel-pasid.c
> > +++ b/drivers/iommu/intel-pasid.c
> > @@ -359,6 +359,76 @@ 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);
>
> The last input should be "value << 32".
>
you are right. will fix.
> > +}
> > +
> > +/*
> > + * 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);
>
> The last input should be "1 << 25".
>
right, i misunderstood the argument of pasid_set_bits(), same for the
other bits below.
> > +}
> > +
> > +/*
> > + * 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);
>
> The last input should be "1 << 26".
>
> > +}
> > +
> > +/*
> > + * 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);
>
> The last input should be "1 << 7".
>
> > +}
> > +
> > +/*
> > + * 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);
>
> The last input should be "1 << 31".
>
> > +}
> > +
> > +/*
> > + * 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);
>
> The last input should be "1 << 30".
>
> > +}
> > +
> > static void
> > pasid_cache_invalidation_with_pasid(struct intel_iommu *iommu,
> > u16 did, int pasid)
> > @@ -599,3 +669,146 @@ 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) {
> > + if (!ecap_eafs(iommu->ecap)) {
> > + pr_err("No extended access flag support on
> > %s\n",
> > + iommu->name);
> > + return -EINVAL;
> > + }
> > + pasid_set_eafe(pte);
> > + }
> > +
> > + /*
> > + * 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)) {
> > + if (pasid_data->flags & IOMMU_SVA_VTD_GPASID_EMTE)
> > {
> > + pasid_set_emte(pte);
> > + pasid_set_emt(pte, pasid_data->emt);
> > + }
> > + 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);
> > + } else if (pasid_data->flags &
> > IOMMU_SVA_VTD_GPASID_EMT_MASK) {
> > + pr_warn("No memory type support for bind guest
> > PASID on %s\n",
> > + iommu->name);
> > + return -EINVAL;
> > + }
> > +
> > + 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
>
> Please remove "which is used for vSVA". It should be a generic
> interface for setting up nested translation mode?
>
Right, perhaps just mention vSVA as an example such that readers can
have some idea of how nested translation can be used? e.g.
"
* intel_pasid_setup_nested() - Set up PASID entry for nested translation.
* This could be used for guest shared virtual address. In this case, the
* first level page tables are used for GVA-GPA translation in the guest,
* second level page tables are used for GPA-HPA translation.
"

> > + * GVA-GPA or GIOVA-GPA translation in the guest, second level
> > page tables
> > + * are used for GPA-HPA translation.
>
> Nit: align with the last line.
>
Will do.
> > + *
> > + * @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 ADDR_WIDTH_5LEVEL:
> > + pasid_set_flpm(pte, 1);
> > + break;
> > + case ADDR_WIDTH_4LEVEL:
> > + pasid_set_flpm(pte, 0);
> > + break;
> > + default:
> > + dev_err(dev, "Invalid paging mode %d\n",
> > addr_width);
>
> Invalid guest address width?
>
Sounds better, will do.
> > + return -EINVAL;
> > + }
> > +
> > + pasid_set_flptr(pte, (u64)gpgd);
> > +
> > + intel_pasid_setup_bind_data(iommu, pte, pasid_data);
>
> Do you want to check and handle the errors returned from this
> function?
>
yes, that would be necessary in case of unsupported bind data. Thanks!
> > +
> > + /* 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)) {
> > + pasid_clear_entry(pte);
> > + 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 fc8cd8f17de1..95ed160b1947
> > 100644 --- a/drivers/iommu/intel-pasid.h
> > +++ b/drivers/iommu/intel-pasid.h
> > @@ -36,6 +36,7 @@
> > * 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;
> > @@ -45,6 +46,11 @@ 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 */ @@ -93,6 +99,12 @@ 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);
> >
> > diff --git a/include/linux/intel-iommu.h
> > b/include/linux/intel-iommu.h index 74b79e2e6a73..19bf9ff180ae
> > 100644 --- a/include/linux/intel-iommu.h
> > +++ b/include/linux/intel-iommu.h
> > @@ -34,6 +34,9 @@
> > #define VTD_STRIDE_SHIFT (9)
> > #define VTD_STRIDE_MASK (((u64)-1) << VTD_STRIDE_SHIFT)
> >
> > +#define ADDR_WIDTH_5LEVEL (57)
> > +#define ADDR_WIDTH_4LEVEL (48)
> > +
> > #define DMA_PTE_READ (1)
> > #define DMA_PTE_WRITE (2)
> > #define DMA_PTE_LARGE_PAGE (1 << 7)
> > diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> > index 4ad3496e5c43..fcafb6401430 100644
> > --- a/include/uapi/linux/iommu.h
> > +++ b/include/uapi/linux/iommu.h
> > @@ -284,7 +284,10 @@ struct iommu_gpasid_bind_data_vtd {
> > __u32 pat;
> > __u32 emt;
> > };
> > -
> > +#define IOMMU_SVA_VTD_GPASID_EMT_MASK
> > (IOMMU_SVA_VTD_GPASID_CD | \
> > + IOMMU_SVA_VTD_GPASID_EMTE
> > | \
> > + IOMMU_SVA_VTD_GPASID_PCD
> > | \
> > +
> > IOMMU_SVA_VTD_GPASID_PWT)
>
> Might need a seperated patch?
>
Sure. I have other uapi changes, may group them as a separate series.

> > /**
> > * struct iommu_gpasid_bind_data - Information about device and
> > guest PASID binding
> > * @version: Version of this data structure
> >
>
> Best regards,
> baolu

[Jacob Pan]