[PATCH v4 0/8] VT-d Native Shared virtual memory cleanup and fixes

[PATCH v4 0/8] VT-d Native Shared virtual memory cleanup and fixes

[Jacob Pan]

Mostly extracted from nested SVA/SVM series based on review comments of v7.
https://lkml.org/lkml/2019/10/24/852

This series also adds a few important fixes for native use of SVA. Nested
SVA new code will be submitted separately as a smaller set. Based on the
core branch of IOMMU tree staged for v5.5, where common APIs for vSVA were
applied.
git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git core

Changelog:
v4	- Commit message fix

V3
	- Squashed 1/10 & 2/10
	- Deleted "8/10 Fix PASID cache flush" from this series
	- Addressed reviews from Eric Auger and Baolu
V2
	- Coding style fixes based on Baolu's input, no functional change
	- Added Acked-by tags.

Thanks,

Jacob


Jacob Pan (8):
  iommu/vt-d: Fix CPU and IOMMU SVM feature matching checks
  iommu/vt-d: Match CPU and IOMMU paging mode
  iommu/vt-d: Reject SVM bind for failed capability check
  iommu/vt-d: Avoid duplicated code for PASID setup
  iommu/vt-d: Fix off-by-one in PASID allocation
  iommu/vt-d: Replace Intel specific PASID allocator with IOASID
  iommu/vt-d: Avoid sending invalid page response
  iommu/vt-d: Misc macro clean up for SVM

 drivers/iommu/Kconfig       |   1 +
 drivers/iommu/intel-iommu.c |  23 +++----
 drivers/iommu/intel-pasid.c |  96 ++++++++------------------
 drivers/iommu/intel-svm.c   | 162 +++++++++++++++++++++++++-------------------
 include/linux/intel-iommu.h |   5 +-
 5 files changed, 134 insertions(+), 153 deletions(-)

-- 
2.7.4

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[PATCH v4 1/8] iommu/vt-d: Fix CPU and IOMMU SVM feature matching checks

[Jacob Pan]

Shared Virtual Memory(SVM) is based on a collective set of hardware
features detected at runtime. There are requirements for matching CPU
and IOMMU capabilities.

The current code checks CPU and IOMMU feature set for SVM support but
the result is never stored nor used. Therefore, SVM can still be used
even when these checks failed. The consequences can be:
1. CPU uses 5-level paging mode for virtual address of 57 bits, but
IOMMU can only support 4-level paging mode with 48 bits address for DMA.
2. 1GB page size is used by CPU but IOMMU does not support it. VT-d
unrecoverable faults may be generated.

The best solution to fix these problems is to prevent them in the first
place.

This patch consolidates code for checking PASID, CPU vs. IOMMU paging
mode compatibility, as well as provides specific error messages for
each failed checks. On sane hardware configurations, these error message
shall never appear in kernel log.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 10 ++--------
 drivers/iommu/intel-svm.c   | 40 +++++++++++++++++++++++++++-------------
 include/linux/intel-iommu.h |  5 ++++-
 3 files changed, 33 insertions(+), 22 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 3f974919d3bd..d598168e410d 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3289,10 +3289,7 @@ static int __init init_dmars(void)
 
 		if (!ecap_pass_through(iommu->ecap))
 			hw_pass_through = 0;
-#ifdef CONFIG_INTEL_IOMMU_SVM
-		if (pasid_supported(iommu))
-			intel_svm_init(iommu);
-#endif
+		intel_svm_check(iommu);
 	}
 
 	/*
@@ -4471,10 +4468,7 @@ static int intel_iommu_add(struct dmar_drhd_unit *dmaru)
 	if (ret)
 		goto out;
 
-#ifdef CONFIG_INTEL_IOMMU_SVM
-	if (pasid_supported(iommu))
-		intel_svm_init(iommu);
-#endif
+	intel_svm_check(iommu);
 
 	if (dmaru->ignored) {
 		/*
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 9b159132405d..716c543488f6 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -23,19 +23,6 @@
 
 static irqreturn_t prq_event_thread(int irq, void *d);
 
-int intel_svm_init(struct intel_iommu *iommu)
-{
-	if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
-			!cap_fl1gp_support(iommu->cap))
-		return -EINVAL;
-
-	if (cpu_feature_enabled(X86_FEATURE_LA57) &&
-			!cap_5lp_support(iommu->cap))
-		return -EINVAL;
-
-	return 0;
-}
-
 #define PRQ_ORDER 0
 
 int intel_svm_enable_prq(struct intel_iommu *iommu)
@@ -99,6 +86,33 @@ int intel_svm_finish_prq(struct intel_iommu *iommu)
 	return 0;
 }
 
+static inline bool intel_svm_capable(struct intel_iommu *iommu)
+{
+	return iommu->flags & VTD_FLAG_SVM_CAPABLE;
+}
+
+void intel_svm_check(struct intel_iommu *iommu)
+{
+	if (!pasid_supported(iommu))
+		return;
+
+	if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
+	    !cap_fl1gp_support(iommu->cap)) {
+		pr_err("%s SVM disabled, incompatible 1GB page capability\n",
+		       iommu->name);
+		return;
+	}
+
+	if (cpu_feature_enabled(X86_FEATURE_LA57) &&
+	    !cap_5lp_support(iommu->cap)) {
+		pr_err("%s SVM disabled, incompatible paging mode\n",
+		       iommu->name);
+		return;
+	}
+
+	iommu->flags |= VTD_FLAG_SVM_CAPABLE;
+}
+
 static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_dev *sdev,
 				unsigned long address, unsigned long pages, int ih)
 {
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index ed11ef594378..7dcfa1c4a844 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -433,6 +433,7 @@ enum {
 
 #define VTD_FLAG_TRANS_PRE_ENABLED	(1 << 0)
 #define VTD_FLAG_IRQ_REMAP_PRE_ENABLED	(1 << 1)
+#define VTD_FLAG_SVM_CAPABLE		(1 << 2)
 
 extern int intel_iommu_sm;
 
@@ -656,7 +657,7 @@ void iommu_flush_write_buffer(struct intel_iommu *iommu);
 int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev);
 
 #ifdef CONFIG_INTEL_IOMMU_SVM
-int intel_svm_init(struct intel_iommu *iommu);
+extern void intel_svm_check(struct intel_iommu *iommu);
 extern int intel_svm_enable_prq(struct intel_iommu *iommu);
 extern int intel_svm_finish_prq(struct intel_iommu *iommu);
 
@@ -684,6 +685,8 @@ struct intel_svm {
 };
 
 extern struct intel_iommu *intel_svm_device_to_iommu(struct device *dev);
+#else
+static inline void intel_svm_check(struct intel_iommu *iommu) {}
 #endif
 
 #ifdef CONFIG_INTEL_IOMMU_DEBUGFS
-- 
2.7.4

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[PATCH v4 2/8] iommu/vt-d: Match CPU and IOMMU paging mode

[Jacob Pan]

When setting up first level page tables for sharing with CPU, we need
to ensure IOMMU can support no less than the levels supported by the
CPU.

It is not adequate, as in the current code, to set up 5-level paging
in PASID entry First Level Paging Mode(FLPM) solely based on CPU.

Currently, intel_pasid_setup_first_level() is only used by native SVM
code which already checks paging mode matches. However, future use of
this helper function may not be limited to native SVM.
https://lkml.org/lkml/2019/11/18/1037

Fixes: 437f35e1cd4c8 ("iommu/vt-d: Add first level page table
interface")
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-pasid.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index 040a445be300..e7cb0b8a7332 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -499,8 +499,16 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu,
 	}
 
 #ifdef CONFIG_X86
-	if (cpu_feature_enabled(X86_FEATURE_LA57))
-		pasid_set_flpm(pte, 1);
+	/* Both CPU and IOMMU paging mode need to match */
+	if (cpu_feature_enabled(X86_FEATURE_LA57)) {
+		if (cap_5lp_support(iommu->cap)) {
+			pasid_set_flpm(pte, 1);
+		} else {
+			pr_err("VT-d has no 5-level paging support for CPU\n");
+			pasid_clear_entry(pte);
+			return -EINVAL;
+		}
+	}
 #endif /* CONFIG_X86 */
 
 	pasid_set_domain_id(pte, did);
-- 
2.7.4

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[PATCH v4 3/8] iommu/vt-d: Reject SVM bind for failed capability check

[Jacob Pan]

Add a check during SVM bind to ensure CPU and IOMMU hardware capabilities
are met.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-svm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 716c543488f6..74df10a39dfc 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -238,6 +238,9 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
 	if (!iommu || dmar_disabled)
 		return -EINVAL;
 
+	if (!intel_svm_capable(iommu))
+		return -ENOTSUPP;
+
 	if (dev_is_pci(dev)) {
 		pasid_max = pci_max_pasids(to_pci_dev(dev));
 		if (pasid_max < 0)
-- 
2.7.4

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[PATCH v4 4/8] iommu/vt-d: Avoid duplicated code for PASID setup

[Jacob Pan]

After each setup for PASID entry, related translation caches must be
flushed. We can combine duplicated code into one function which is less
error prone.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-pasid.c | 48 +++++++++++++++++----------------------------
 1 file changed, 18 insertions(+), 30 deletions(-)

diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index e7cb0b8a7332..732bfee228df 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -465,6 +465,21 @@ void intel_pasid_tear_down_entry(struct intel_iommu *iommu,
 		devtlb_invalidation_with_pasid(iommu, dev, pasid);
 }
 
+static void pasid_flush_caches(struct intel_iommu *iommu,
+				struct pasid_entry *pte,
+				int pasid, u16 did)
+{
+	if (!ecap_coherent(iommu->ecap))
+		clflush_cache_range(pte, sizeof(*pte));
+
+	if (cap_caching_mode(iommu->cap)) {
+		pasid_cache_invalidation_with_pasid(iommu, did, pasid);
+		iotlb_invalidation_with_pasid(iommu, did, pasid);
+	} else {
+		iommu_flush_write_buffer(iommu);
+	}
+}
+
 /*
  * Set up the scalable mode pasid table entry for first only
  * translation type.
@@ -518,16 +533,7 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu,
 	/* Setup Present and PASID Granular Transfer Type: */
 	pasid_set_translation_type(pte, 1);
 	pasid_set_present(pte);
-
-	if (!ecap_coherent(iommu->ecap))
-		clflush_cache_range(pte, sizeof(*pte));
-
-	if (cap_caching_mode(iommu->cap)) {
-		pasid_cache_invalidation_with_pasid(iommu, did, pasid);
-		iotlb_invalidation_with_pasid(iommu, did, pasid);
-	} else {
-		iommu_flush_write_buffer(iommu);
-	}
+	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
 }
@@ -591,16 +597,7 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
 	 */
 	pasid_set_sre(pte);
 	pasid_set_present(pte);
-
-	if (!ecap_coherent(iommu->ecap))
-		clflush_cache_range(pte, sizeof(*pte));
-
-	if (cap_caching_mode(iommu->cap)) {
-		pasid_cache_invalidation_with_pasid(iommu, did, pasid);
-		iotlb_invalidation_with_pasid(iommu, did, pasid);
-	} else {
-		iommu_flush_write_buffer(iommu);
-	}
+	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
 }
@@ -634,16 +631,7 @@ int intel_pasid_setup_pass_through(struct intel_iommu *iommu,
 	 */
 	pasid_set_sre(pte);
 	pasid_set_present(pte);
-
-	if (!ecap_coherent(iommu->ecap))
-		clflush_cache_range(pte, sizeof(*pte));
-
-	if (cap_caching_mode(iommu->cap)) {
-		pasid_cache_invalidation_with_pasid(iommu, did, pasid);
-		iotlb_invalidation_with_pasid(iommu, did, pasid);
-	} else {
-		iommu_flush_write_buffer(iommu);
-	}
+	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
 }
-- 
2.7.4

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[PATCH v4 5/8] iommu/vt-d: Fix off-by-one in PASID allocation

[Jacob Pan]

PASID allocator uses IDR which is exclusive for the end of the
allocation range. There is no need to decrement pasid_max.

Fixes: af39507305fb ("iommu/vt-d: Apply global PASID in SVA")
Reported-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-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 74df10a39dfc..e90d0b914afe 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -338,7 +338,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
 		/* Do not use PASID 0 in caching mode (virtualised IOMMU) */
 		ret = intel_pasid_alloc_id(svm,
 					   !!cap_caching_mode(iommu->cap),
-					   pasid_max - 1, GFP_KERNEL);
+					   pasid_max, GFP_KERNEL);
 		if (ret < 0) {
 			kfree(svm);
 			kfree(sdev);
-- 
2.7.4

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[PATCH v4 6/8] iommu/vt-d: Replace Intel specific PASID allocator with IOASID

[Jacob Pan]

Make use of generic IOASID code to manage PASID allocation,
free, and lookup. Replace Intel specific code.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/Kconfig       |  1 +
 drivers/iommu/intel-iommu.c | 13 +++++++------
 drivers/iommu/intel-pasid.c | 36 ------------------------------------
 drivers/iommu/intel-svm.c   | 39 +++++++++++++++++++++++++--------------
 4 files changed, 33 insertions(+), 56 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index fd50ddffffbf..43ce450a40d3 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -212,6 +212,7 @@ config INTEL_IOMMU_SVM
 	depends on INTEL_IOMMU && X86
 	select PCI_PASID
 	select MMU_NOTIFIER
+	select IOASID
 	help
 	  Shared Virtual Memory (SVM) provides a facility for devices
 	  to access DMA resources through process address space by
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index d598168e410d..a84f0caa33a0 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5238,7 +5238,7 @@ static void auxiliary_unlink_device(struct dmar_domain *domain,
 	domain->auxd_refcnt--;
 
 	if (!domain->auxd_refcnt && domain->default_pasid > 0)
-		intel_pasid_free_id(domain->default_pasid);
+		ioasid_free(domain->default_pasid);
 }
 
 static int aux_domain_add_dev(struct dmar_domain *domain,
@@ -5256,10 +5256,11 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
 	if (domain->default_pasid <= 0) {
 		int pasid;
 
-		pasid = intel_pasid_alloc_id(domain, PASID_MIN,
-					     pci_max_pasids(to_pci_dev(dev)),
-					     GFP_KERNEL);
-		if (pasid <= 0) {
+		/* No private data needed for the default pasid */
+		pasid = ioasid_alloc(NULL, PASID_MIN,
+				     pci_max_pasids(to_pci_dev(dev)) - 1,
+				     NULL);
+		if (pasid == INVALID_IOASID) {
 			pr_err("Can't allocate default pasid\n");
 			return -ENODEV;
 		}
@@ -5295,7 +5296,7 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
 	spin_unlock(&iommu->lock);
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 	if (!domain->auxd_refcnt && domain->default_pasid > 0)
-		intel_pasid_free_id(domain->default_pasid);
+		ioasid_free(domain->default_pasid);
 
 	return ret;
 }
diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index 732bfee228df..3cb569e76642 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -26,42 +26,6 @@
  */
 static DEFINE_SPINLOCK(pasid_lock);
 u32 intel_pasid_max_id = PASID_MAX;
-static DEFINE_IDR(pasid_idr);
-
-int intel_pasid_alloc_id(void *ptr, int start, int end, gfp_t gfp)
-{
-	int ret, min, max;
-
-	min = max_t(int, start, PASID_MIN);
-	max = min_t(int, end, intel_pasid_max_id);
-
-	WARN_ON(in_interrupt());
-	idr_preload(gfp);
-	spin_lock(&pasid_lock);
-	ret = idr_alloc(&pasid_idr, ptr, min, max, GFP_ATOMIC);
-	spin_unlock(&pasid_lock);
-	idr_preload_end();
-
-	return ret;
-}
-
-void intel_pasid_free_id(int pasid)
-{
-	spin_lock(&pasid_lock);
-	idr_remove(&pasid_idr, pasid);
-	spin_unlock(&pasid_lock);
-}
-
-void *intel_pasid_lookup_id(int pasid)
-{
-	void *p;
-
-	spin_lock(&pasid_lock);
-	p = idr_find(&pasid_idr, pasid);
-	spin_unlock(&pasid_lock);
-
-	return p;
-}
 
 /*
  * Per device pasid table management:
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index e90d0b914afe..71b85b892c56 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -17,6 +17,7 @@
 #include <linux/dmar.h>
 #include <linux/interrupt.h>
 #include <linux/mm_types.h>
+#include <linux/ioasid.h>
 #include <asm/page.h>
 
 #include "intel-pasid.h"
@@ -335,16 +336,15 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
 		if (pasid_max > intel_pasid_max_id)
 			pasid_max = intel_pasid_max_id;
 
-		/* Do not use PASID 0 in caching mode (virtualised IOMMU) */
-		ret = intel_pasid_alloc_id(svm,
-					   !!cap_caching_mode(iommu->cap),
-					   pasid_max, GFP_KERNEL);
-		if (ret < 0) {
+		/* Do not use PASID 0, reserved for RID to PASID */
+		svm->pasid = ioasid_alloc(NULL, PASID_MIN,
+					  pasid_max - 1, svm);
+		if (svm->pasid == INVALID_IOASID) {
 			kfree(svm);
 			kfree(sdev);
+			ret = -ENOSPC;
 			goto out;
 		}
-		svm->pasid = ret;
 		svm->notifier.ops = &intel_mmuops;
 		svm->mm = mm;
 		svm->flags = flags;
@@ -354,7 +354,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
 		if (mm) {
 			ret = mmu_notifier_register(&svm->notifier, mm);
 			if (ret) {
-				intel_pasid_free_id(svm->pasid);
+				ioasid_free(svm->pasid);
 				kfree(svm);
 				kfree(sdev);
 				goto out;
@@ -370,7 +370,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
 		if (ret) {
 			if (mm)
 				mmu_notifier_unregister(&svm->notifier, mm);
-			intel_pasid_free_id(svm->pasid);
+			ioasid_free(svm->pasid);
 			kfree(svm);
 			kfree(sdev);
 			goto out;
@@ -418,7 +418,15 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
 	if (!iommu)
 		goto out;
 
-	svm = intel_pasid_lookup_id(pasid);
+	svm = ioasid_find(NULL, pasid, NULL);
+	if (!svm)
+		goto out;
+
+	if (IS_ERR(svm)) {
+		ret = PTR_ERR(svm);
+		goto out;
+	}
+
 	if (!svm)
 		goto out;
 
@@ -440,7 +448,7 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
 				kfree_rcu(sdev, rcu);
 
 				if (list_empty(&svm->devs)) {
-					intel_pasid_free_id(svm->pasid);
+					ioasid_free(svm->pasid);
 					if (svm->mm)
 						mmu_notifier_unregister(&svm->notifier, svm->mm);
 
@@ -475,10 +483,14 @@ int intel_svm_is_pasid_valid(struct device *dev, int pasid)
 	if (!iommu)
 		goto out;
 
-	svm = intel_pasid_lookup_id(pasid);
+	svm = ioasid_find(NULL, pasid, NULL);
 	if (!svm)
 		goto out;
 
+	if (IS_ERR(svm)) {
+		ret = PTR_ERR(svm);
+		goto out;
+	}
 	/* init_mm is used in this case */
 	if (!svm->mm)
 		ret = 1;
@@ -585,13 +597,12 @@ static irqreturn_t prq_event_thread(int irq, void *d)
 
 		if (!svm || svm->pasid != req->pasid) {
 			rcu_read_lock();
-			svm = intel_pasid_lookup_id(req->pasid);
+			svm = ioasid_find(NULL, req->pasid, NULL);
 			/* It *can't* go away, because the driver is not permitted
 			 * to unbind the mm while any page faults are outstanding.
 			 * So we only need RCU to protect the internal idr code. */
 			rcu_read_unlock();
-
-			if (!svm) {
+			if (IS_ERR_OR_NULL(svm)) {
 				pr_err("%s: Page request for invalid PASID %d: %08llx %08llx\n",
 				       iommu->name, req->pasid, ((unsigned long long *)req)[0],
 				       ((unsigned long long *)req)[1]);
-- 
2.7.4

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[PATCH v4 7/8] iommu/vt-d: Avoid sending invalid page response

[Jacob Pan]

Page responses should only be sent when last page in group (LPIG) or
private data is present in the page request. This patch avoids sending
invalid descriptors.

Fixes: 5d308fc1ecf53 ("iommu/vt-d: Add 256-bit invalidation descriptor
support")
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-svm.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 71b85b892c56..4eecc24412dc 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -686,11 +686,10 @@ static irqreturn_t prq_event_thread(int irq, void *d)
 			if (req->priv_data_present)
 				memcpy(&resp.qw2, req->priv_data,
 				       sizeof(req->priv_data));
+			resp.qw2 = 0;
+			resp.qw3 = 0;
+			qi_submit_sync(&resp, iommu);
 		}
-		resp.qw2 = 0;
-		resp.qw3 = 0;
-		qi_submit_sync(&resp, iommu);
-
 		head = (head + sizeof(*req)) & PRQ_RING_MASK;
 	}
 
-- 
2.7.4

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[PATCH v4 8/8] iommu/vt-d: Misc macro clean up for SVM

[Jacob Pan]

Use combined macros for_each_svm_dev() to simplify SVM device iteration
and error checking.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-svm.c | 81 ++++++++++++++++++++++-------------------------
 1 file changed, 38 insertions(+), 43 deletions(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 4eecc24412dc..5b4224871e34 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -226,6 +226,10 @@ static const struct mmu_notifier_ops intel_mmuops = {
 static DEFINE_MUTEX(pasid_mutex);
 static LIST_HEAD(global_svm_list);
 
+#define for_each_svm_dev(sdev, svm, d)			\
+	list_for_each_entry((sdev), &(svm)->devs, list)	\
+		if ((d) != (sdev)->dev) {} else
+
 int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops *ops)
 {
 	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
@@ -274,15 +278,13 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
 				goto out;
 			}
 
-			list_for_each_entry(sdev, &svm->devs, list) {
-				if (dev == sdev->dev) {
-					if (sdev->ops != ops) {
-						ret = -EBUSY;
-						goto out;
-					}
-					sdev->users++;
-					goto success;
+			for_each_svm_dev(sdev, svm, dev) {
+				if (sdev->ops != ops) {
+					ret = -EBUSY;
+					goto out;
 				}
+				sdev->users++;
+				goto success;
 			}
 
 			break;
@@ -427,43 +429,36 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
 		goto out;
 	}
 
-	if (!svm)
-		goto out;
-
-	list_for_each_entry(sdev, &svm->devs, list) {
-		if (dev == sdev->dev) {
-			ret = 0;
-			sdev->users--;
-			if (!sdev->users) {
-				list_del_rcu(&sdev->list);
-				/* Flush the PASID cache and IOTLB for this device.
-				 * Note that we do depend on the hardware *not* using
-				 * the PASID any more. Just as we depend on other
-				 * devices never using PASIDs that they have no right
-				 * to use. We have a *shared* PASID table, because it's
-				 * large and has to be physically contiguous. So it's
-				 * hard to be as defensive as we might like. */
-				intel_pasid_tear_down_entry(iommu, dev, svm->pasid);
-				intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
-				kfree_rcu(sdev, rcu);
-
-				if (list_empty(&svm->devs)) {
-					ioasid_free(svm->pasid);
-					if (svm->mm)
-						mmu_notifier_unregister(&svm->notifier, svm->mm);
-
-					list_del(&svm->list);
-
-					/* We mandate that no page faults may be outstanding
-					 * for the PASID when intel_svm_unbind_mm() is called.
-					 * If that is not obeyed, subtle errors will happen.
-					 * Let's make them less subtle... */
-					memset(svm, 0x6b, sizeof(*svm));
-					kfree(svm);
-				}
+	for_each_svm_dev(sdev, svm, dev) {
+		ret = 0;
+		sdev->users--;
+		if (!sdev->users) {
+			list_del_rcu(&sdev->list);
+			/* Flush the PASID cache and IOTLB for this device.
+			 * Note that we do depend on the hardware *not* using
+			 * the PASID any more. Just as we depend on other
+			 * devices never using PASIDs that they have no right
+			 * to use. We have a *shared* PASID table, because it's
+			 * large and has to be physically contiguous. So it's
+			 * hard to be as defensive as we might like. */
+			intel_pasid_tear_down_entry(iommu, dev, svm->pasid);
+			intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
+			kfree_rcu(sdev, rcu);
+
+			if (list_empty(&svm->devs)) {
+				ioasid_free(svm->pasid);
+				if (svm->mm)
+					mmu_notifier_unregister(&svm->notifier, svm->mm);
+				list_del(&svm->list);
+				/* We mandate that no page faults may be outstanding
+				 * for the PASID when intel_svm_unbind_mm() is called.
+				 * If that is not obeyed, subtle errors will happen.
+				 * Let's make them less subtle... */
+				memset(svm, 0x6b, sizeof(*svm));
+				kfree(svm);
 			}
-			break;
 		}
+		break;
 	}
  out:
 	mutex_unlock(&pasid_mutex);
-- 
2.7.4

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Re: [PATCH v4 8/8] iommu/vt-d: Misc macro clean up for SVM

[Joe Perches]

On Thu, 2019-11-21 at 13:26 -0800, Jacob Pan wrote:
> Use combined macros for_each_svm_dev() to simplify SVM device iteration
> and error checking.
[]
> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
[]
> +#define for_each_svm_dev(sdev, svm, d)			\
> +	list_for_each_entry((sdev), &(svm)->devs, list)	\
> +		if ((d) != (sdev)->dev) {} else
> +
>  int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops *ops)
>  {
>  	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
> @@ -274,15 +278,13 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
>  				goto out;
>  			}
>  
> -			list_for_each_entry(sdev, &svm->devs, list) {
> -				if (dev == sdev->dev) {
> -					if (sdev->ops != ops) {
> -						ret = -EBUSY;
> -						goto out;
> -					}
> -					sdev->users++;
> -					goto success;
> +			for_each_svm_dev(sdev, svm, dev) {
> +				if (sdev->ops != ops) {
> +					ret = -EBUSY;
> +					goto out;
>  				}
> +				sdev->users++;
> +				goto success;
>  			}

I think this does not read better as this is now a
for_each loop that exits the loop on the first match.

>  
>  			break;
> @@ -427,43 +429,36 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
>  		goto out;
>  	}
>  
> -	if (!svm)
> -		goto out;
> -
> -	list_for_each_entry(sdev, &svm->devs, list) {
[]
> +	for_each_svm_dev(sdev, svm, dev) {

I think this should not remove the !svm test above.


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Re: [PATCH v4 8/8] iommu/vt-d: Misc macro clean up for SVM

[Jacob Pan]

On Thu, 21 Nov 2019 13:37:10 -0800
Joe Perches <joe@perches.com> wrote:

> On Thu, 2019-11-21 at 13:26 -0800, Jacob Pan wrote:
> > Use combined macros for_each_svm_dev() to simplify SVM device
> > iteration and error checking.  
> []
> > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c  
> []
> > +#define for_each_svm_dev(sdev, svm, d)			\
> > +	list_for_each_entry((sdev), &(svm)->devs, list)	\
> > +		if ((d) != (sdev)->dev) {} else
> > +
> >  int intel_svm_bind_mm(struct device *dev, int *pasid, int flags,
> > struct svm_dev_ops *ops) {
> >  	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
> > @@ -274,15 +278,13 @@ int intel_svm_bind_mm(struct device *dev, int
> > *pasid, int flags, struct svm_dev_ goto out;
> >  			}
> >  
> > -			list_for_each_entry(sdev, &svm->devs,
> > list) {
> > -				if (dev == sdev->dev) {
> > -					if (sdev->ops != ops) {
> > -						ret = -EBUSY;
> > -						goto out;
> > -					}
> > -					sdev->users++;
> > -					goto success;
> > +			for_each_svm_dev(sdev, svm, dev) {
> > +				if (sdev->ops != ops) {
> > +					ret = -EBUSY;
> > +					goto out;
> >  				}
> > +				sdev->users++;
> > +				goto success;
> >  			}  
> 
> I think this does not read better as this is now a
> for_each loop that exits the loop on the first match.
> 
I think one of the benefits is reduced indentation. What do you
recommend?

> >  
> >  			break;
> > @@ -427,43 +429,36 @@ int intel_svm_unbind_mm(struct device *dev,
> > int pasid) goto out;
> >  	}
> >  
> > -	if (!svm)
> > -		goto out;
> > -
> > -	list_for_each_entry(sdev, &svm->devs, list) {  
> []
> > +	for_each_svm_dev(sdev, svm, dev) {  
> 
> I think this should not remove the !svm test above.
> 
Yeah, !svm test should have been part of 6/8. I will fix that.

Thanks,

Jacob 
> 

[Jacob Pan]
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Re: [PATCH v4 8/8] iommu/vt-d: Misc macro clean up for SVM

[Joe Perches]

On Mon, 2019-12-02 at 10:15 -0800, Jacob Pan wrote:
> On Thu, 21 Nov 2019 13:37:10 -0800
> Joe Perches <joe@perches.com> wrote:
> 
> > On Thu, 2019-11-21 at 13:26 -0800, Jacob Pan wrote:
> > > Use combined macros for_each_svm_dev() to simplify SVM device
> > > iteration and error checking.  
> > []
> > > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c  
> > []
> > > +#define for_each_svm_dev(sdev, svm, d)			\
> > > +	list_for_each_entry((sdev), &(svm)->devs, list)	\
> > > +		if ((d) != (sdev)->dev) {} else
> > > +
> > >  int intel_svm_bind_mm(struct device *dev, int *pasid, int flags,
> > > struct svm_dev_ops *ops) {
> > >  	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
> > > @@ -274,15 +278,13 @@ int intel_svm_bind_mm(struct device *dev, int
> > > *pasid, int flags, struct svm_dev_ goto out;
> > >  			}
> > >  
> > > -			list_for_each_entry(sdev, &svm->devs,
> > > list) {
> > > -				if (dev == sdev->dev) {
> > > -					if (sdev->ops != ops) {
> > > -						ret = -EBUSY;
> > > -						goto out;
> > > -					}
> > > -					sdev->users++;
> > > -					goto success;
> > > +			for_each_svm_dev(sdev, svm, dev) {
> > > +				if (sdev->ops != ops) {
> > > +					ret = -EBUSY;
> > > +					goto out;
> > >  				}
> > > +				sdev->users++;
> > > +				goto success;
> > >  			}  
> > 
> > I think this does not read better as this is now a
> > for_each loop that exits the loop on the first match.
> > 
> I think one of the benefits is reduced indentation. What do you
> recommend?

Making the code intelligible for a reader.

At least add a comment describing why there is only
a single possible match.

Given the for_each name, it's odd code that only the
first match has an action.


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Re: [PATCH v4 8/8] iommu/vt-d: Misc macro clean up for SVM

[Jacob Pan]

On Mon, 02 Dec 2019 10:22:13 -0800
Joe Perches <joe@perches.com> wrote:

> On Mon, 2019-12-02 at 10:15 -0800, Jacob Pan wrote:
> > On Thu, 21 Nov 2019 13:37:10 -0800
> > Joe Perches <joe@perches.com> wrote:
> >   
> > > On Thu, 2019-11-21 at 13:26 -0800, Jacob Pan wrote:  
> > > > Use combined macros for_each_svm_dev() to simplify SVM device
> > > > iteration and error checking.    
> > > []  
> > > > diff --git a/drivers/iommu/intel-svm.c
> > > > b/drivers/iommu/intel-svm.c    
> > > []  
> > > > +#define for_each_svm_dev(sdev, svm, d)			\
> > > > +	list_for_each_entry((sdev), &(svm)->devs, list)
> > > > \
> > > > +		if ((d) != (sdev)->dev) {} else
> > > > +
> > > >  int intel_svm_bind_mm(struct device *dev, int *pasid, int
> > > > flags, struct svm_dev_ops *ops) {
> > > >  	struct intel_iommu *iommu =
> > > > intel_svm_device_to_iommu(dev); @@ -274,15 +278,13 @@ int
> > > > intel_svm_bind_mm(struct device *dev, int *pasid, int flags,
> > > > struct svm_dev_ goto out; }
> > > >  
> > > > -			list_for_each_entry(sdev, &svm->devs,
> > > > list) {
> > > > -				if (dev == sdev->dev) {
> > > > -					if (sdev->ops != ops) {
> > > > -						ret = -EBUSY;
> > > > -						goto out;
> > > > -					}
> > > > -					sdev->users++;
> > > > -					goto success;
> > > > +			for_each_svm_dev(sdev, svm, dev) {
> > > > +				if (sdev->ops != ops) {
> > > > +					ret = -EBUSY;
> > > > +					goto out;
> > > >  				}
> > > > +				sdev->users++;
> > > > +				goto success;
> > > >  			}    
> > > 
> > > I think this does not read better as this is now a
> > > for_each loop that exits the loop on the first match.
> > >   
> > I think one of the benefits is reduced indentation. What do you
> > recommend?  
> 
> Making the code intelligible for a reader.
> 
> At least add a comment describing why there is only
> a single possible match.
> 
> Given the for_each name, it's odd code that only the
> first match has an action.
> 
I will add a comment to explain we are trying to find the matching
device on the list.

Thanks
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