[PATCH v2 0/5] iommu/vt-d: Several misc fixes

[PATCH v2 0/5] iommu/vt-d: Several misc fixes

[Lu Baolu]

Hi Joerg,

This series includes some misc fixes for the VT-d iommu driver. Please
help to review and merge.

Best regards,
baolu

Change log:
 v1->v2:
  - v1: https://lore.kernel.org/linux-iommu/20210225062654.2864322-1-baolu.lu@linux.intel.com/
  - [PATCH 2/5] iommu/vt-d: Remove WO permissions on second-level paging entries
     - Refine the commit message to make the intention clear.

Lu Baolu (5):
  iommu/vt-d: Report the right page fault address
  iommu/vt-d: Remove WO permissions on second-level paging entries
  iommu/vt-d: Invalidate PASID cache when root/context entry changed
  iommu/vt-d: Use user privilege for RID2PASID translation
  iommu/vt-d: Avoid unnecessary cache flush in pasid entry teardown

 drivers/iommu/intel/iommu.c | 28 ++++++++++++++++------------
 drivers/iommu/intel/pasid.c |  6 +++++-
 drivers/iommu/intel/svm.c   |  2 +-
 include/linux/intel-iommu.h |  1 +
 4 files changed, 23 insertions(+), 14 deletions(-)

-- 
2.25.1

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[PATCH v2 1/5] iommu/vt-d: Report the right page fault address

[Lu Baolu]

The Address field of the Page Request Descriptor only keeps bit [63:12]
of the offending address. Convert it to a full address before reporting
it to device drivers.

Fixes: eb8d93ea3c1d3 ("iommu/vt-d: Report page request faults for guest SVA")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/svm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 54db58945c2d..677d7f6b43bb 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -862,7 +862,7 @@ intel_svm_prq_report(struct device *dev, struct page_req_dsc *desc)
 	/* Fill in event data for device specific processing */
 	memset(&event, 0, sizeof(struct iommu_fault_event));
 	event.fault.type = IOMMU_FAULT_PAGE_REQ;
-	event.fault.prm.addr = desc->addr;
+	event.fault.prm.addr = (u64)desc->addr << VTD_PAGE_SHIFT;
 	event.fault.prm.pasid = desc->pasid;
 	event.fault.prm.grpid = desc->prg_index;
 	event.fault.prm.perm = prq_to_iommu_prot(desc);
-- 
2.25.1

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[PATCH v2 2/5] iommu/vt-d: Remove WO permissions on second-level paging entries

[Lu Baolu]

When the first level page table is used for IOVA translation, it only
supports Read-Only and Read-Write permissions. The Write-Only permission
is not supported as the PRESENT bit (implying Read permission) should
always set. When using second level, we still give separate permissions
that allows WriteOnly which seems inconsistent and awkward. We want to
have consistent behavior. After moving to 1st level, we don't want things
to work sometimes, and break if we use 2nd level for the same mappings.
Hence remove this configuration.

Suggested-by: Ashok Raj <ashok.raj@intel.com>
Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 167219ea8d70..132cbf9f214f 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2304,8 +2304,9 @@ __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
 		return -EINVAL;
 
 	attr = prot & (DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP);
+	attr |= DMA_FL_PTE_PRESENT;
 	if (domain_use_first_level(domain)) {
-		attr |= DMA_FL_PTE_PRESENT | DMA_FL_PTE_XD | DMA_FL_PTE_US;
+		attr |= DMA_FL_PTE_XD | DMA_FL_PTE_US;
 
 		if (domain->domain.type == IOMMU_DOMAIN_DMA) {
 			attr |= DMA_FL_PTE_ACCESS;
-- 
2.25.1

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[PATCH v2 3/5] iommu/vt-d: Invalidate PASID cache when root/context entry changed

[Lu Baolu]

When the Intel IOMMU is operating in the scalable mode, some information
from the root and context table may be used to tag entries in the PASID
cache. Software should invalidate the PASID-cache when changing root or
context table entries.

Suggested-by: Ashok Raj <ashok.raj@intel.com>
Fixes: 7373a8cc38197 ("iommu/vt-d: Setup context and enable RID2PASID support")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 18 +++++++++---------
 include/linux/intel-iommu.h |  1 +
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 132cbf9f214f..868f195f55ff 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1339,6 +1339,11 @@ static void iommu_set_root_entry(struct intel_iommu *iommu)
 		      readl, (sts & DMA_GSTS_RTPS), sts);
 
 	raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
+
+	iommu->flush.flush_context(iommu, 0, 0, 0, DMA_CCMD_GLOBAL_INVL);
+	if (sm_supported(iommu))
+		qi_flush_pasid_cache(iommu, 0, QI_PC_GLOBAL, 0);
+	iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH);
 }
 
 void iommu_flush_write_buffer(struct intel_iommu *iommu)
@@ -2422,6 +2427,10 @@ static void domain_context_clear_one(struct intel_iommu *iommu, u8 bus, u8 devfn
 				   (((u16)bus) << 8) | devfn,
 				   DMA_CCMD_MASK_NOBIT,
 				   DMA_CCMD_DEVICE_INVL);
+
+	if (sm_supported(iommu))
+		qi_flush_pasid_cache(iommu, did_old, QI_PC_ALL_PASIDS, 0);
+
 	iommu->flush.flush_iotlb(iommu,
 				 did_old,
 				 0,
@@ -3267,8 +3276,6 @@ static int __init init_dmars(void)
 		register_pasid_allocator(iommu);
 #endif
 		iommu_set_root_entry(iommu);
-		iommu->flush.flush_context(iommu, 0, 0, 0, DMA_CCMD_GLOBAL_INVL);
-		iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH);
 	}
 
 #ifdef CONFIG_INTEL_IOMMU_BROKEN_GFX_WA
@@ -3458,12 +3465,7 @@ static int init_iommu_hw(void)
 		}
 
 		iommu_flush_write_buffer(iommu);
-
 		iommu_set_root_entry(iommu);
-
-		iommu->flush.flush_context(iommu, 0, 0, 0,
-					   DMA_CCMD_GLOBAL_INVL);
-		iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH);
 		iommu_enable_translation(iommu);
 		iommu_disable_protect_mem_regions(iommu);
 	}
@@ -3846,8 +3848,6 @@ static int intel_iommu_add(struct dmar_drhd_unit *dmaru)
 		goto disable_iommu;
 
 	iommu_set_root_entry(iommu);
-	iommu->flush.flush_context(iommu, 0, 0, 0, DMA_CCMD_GLOBAL_INVL);
-	iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH);
 	iommu_enable_translation(iommu);
 
 	iommu_disable_protect_mem_regions(iommu);
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 1732298ce888..76f974da8ca4 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -378,6 +378,7 @@ enum {
 /* PASID cache invalidation granu */
 #define QI_PC_ALL_PASIDS	0
 #define QI_PC_PASID_SEL		1
+#define QI_PC_GLOBAL		3
 
 #define QI_EIOTLB_ADDR(addr)	((u64)(addr) & VTD_PAGE_MASK)
 #define QI_EIOTLB_IH(ih)	(((u64)ih) << 6)
-- 
2.25.1

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[PATCH v2 4/5] iommu/vt-d: Use user privilege for RID2PASID translation

[Lu Baolu]

When first-level page tables are used for IOVA translation, we use user
privilege by setting U/S bit in the page table entry. This is to make it
consistent with the second level translation, where the U/S enforcement
is not available. Clear the SRE (Supervisor Request Enable) field in the
pasid table entry of RID2PASID so that requests requesting the supervisor
privilege are blocked and treated as DMA remapping faults.

Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 7 +++++--
 drivers/iommu/intel/pasid.c | 3 ++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 868f195f55ff..7354f9ce47d8 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2494,9 +2494,9 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
 				    struct device *dev,
 				    u32 pasid)
 {
-	int flags = PASID_FLAG_SUPERVISOR_MODE;
 	struct dma_pte *pgd = domain->pgd;
 	int agaw, level;
+	int flags = 0;
 
 	/*
 	 * Skip top levels of page tables for iommu which has
@@ -2512,7 +2512,10 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
 	if (level != 4 && level != 5)
 		return -EINVAL;
 
-	flags |= (level == 5) ? PASID_FLAG_FL5LP : 0;
+	if (pasid != PASID_RID2PASID)
+		flags |= PASID_FLAG_SUPERVISOR_MODE;
+	if (level == 5)
+		flags |= PASID_FLAG_FL5LP;
 
 	return intel_pasid_setup_first_level(iommu, dev, (pgd_t *)pgd, pasid,
 					     domain->iommu_did[iommu->seq_id],
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 0bf7e0a76890..dd69df5a188a 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -673,7 +673,8 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
 	 * Since it is a second level only translation setup, we should
 	 * set SRE bit as well (addresses are expected to be GPAs).
 	 */
-	pasid_set_sre(pte);
+	if (pasid != PASID_RID2PASID)
+		pasid_set_sre(pte);
 	pasid_set_present(pte);
 	pasid_flush_caches(iommu, pte, pasid, did);
 
-- 
2.25.1

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Re: [PATCH v2 4/5] iommu/vt-d: Use user privilege for RID2PASID translation

[Lu Baolu]

On 3/20/21 10:54 AM, Lu Baolu wrote:
> When first-level page tables are used for IOVA translation, we use user
> privilege by setting U/S bit in the page table entry. This is to make it
> consistent with the second level translation, where the U/S enforcement
> is not available. Clear the SRE (Supervisor Request Enable) field in the
> pasid table entry of RID2PASID so that requests requesting the supervisor
> privilege are blocked and treated as DMA remapping faults.
> 
> Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

We found some devices still require SRE to be set during internal tests.
I will drop this patch from my queue for v5.13 for now.

Best regards,
baolu

> ---
>   drivers/iommu/intel/iommu.c | 7 +++++--
>   drivers/iommu/intel/pasid.c | 3 ++-
>   2 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 868f195f55ff..7354f9ce47d8 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -2494,9 +2494,9 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
>   				    struct device *dev,
>   				    u32 pasid)
>   {
> -	int flags = PASID_FLAG_SUPERVISOR_MODE;
>   	struct dma_pte *pgd = domain->pgd;
>   	int agaw, level;
> +	int flags = 0;
>   
>   	/*
>   	 * Skip top levels of page tables for iommu which has
> @@ -2512,7 +2512,10 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
>   	if (level != 4 && level != 5)
>   		return -EINVAL;
>   
> -	flags |= (level == 5) ? PASID_FLAG_FL5LP : 0;
> +	if (pasid != PASID_RID2PASID)
> +		flags |= PASID_FLAG_SUPERVISOR_MODE;
> +	if (level == 5)
> +		flags |= PASID_FLAG_FL5LP;
>   
>   	return intel_pasid_setup_first_level(iommu, dev, (pgd_t *)pgd, pasid,
>   					     domain->iommu_did[iommu->seq_id],
> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> index 0bf7e0a76890..dd69df5a188a 100644
> --- a/drivers/iommu/intel/pasid.c
> +++ b/drivers/iommu/intel/pasid.c
> @@ -673,7 +673,8 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
>   	 * Since it is a second level only translation setup, we should
>   	 * set SRE bit as well (addresses are expected to be GPAs).
>   	 */
> -	pasid_set_sre(pte);
> +	if (pasid != PASID_RID2PASID)
> +		pasid_set_sre(pte);
>   	pasid_set_present(pte);
>   	pasid_flush_caches(iommu, pte, pasid, did);
>   
> 
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[PATCH v2 5/5] iommu/vt-d: Avoid unnecessary cache flush in pasid entry teardown

[Lu Baolu]

When a present pasid entry is disassembled, all kinds of pasid related
caches need to be flushed. But when a pasid entry is not being used
(PRESENT bit not set), we don't need to do this. Check the PRESENT bit
in intel_pasid_tear_down_entry() and avoid flushing caches if it's not
set.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/pasid.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index dd69df5a188a..7a73385edcc0 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -502,6 +502,9 @@ void intel_pasid_tear_down_entry(struct intel_iommu *iommu, struct device *dev,
 	if (WARN_ON(!pte))
 		return;
 
+	if (!(pte->val[0] & PASID_PTE_PRESENT))
+		return;
+
 	did = pasid_get_domain_id(pte);
 	intel_pasid_clear_entry(dev, pasid, fault_ignore);
 
-- 
2.25.1

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