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* [PATCH 0/6] iommu/amd: Locking Fixes
@ 2019-09-25 13:22 Joerg Roedel
  2019-09-25 13:22 ` [PATCH 1/6] iommu/amd: Remove domain->updated Joerg Roedel
                   ` (6 more replies)
  0 siblings, 7 replies; 22+ messages in thread
From: Joerg Roedel @ 2019-09-25 13:22 UTC (permalink / raw)
  To: iommu, Joerg Roedel; +Cc: Filippo Sironi, jroedel

Hi,

here are a couple of fixes for the amd iommu driver to fix a
few locking issues around protection-domains. Main problem
was that some traversals of ->dev_list were not locked in
any form, causing potential race conditions.

But there are more issues fixed here, for example the racy
access to protection_domain->updated and races in the
attach/detach_device code paths.

Changes are boot-tested with lockdep enabled, looked all
good so far.

Please review.

Thanks,

	Joerg

Joerg Roedel (6):
  iommu/amd: Remove domain->updated
  iommu/amd: Remove amd_iommu_devtable_lock
  iommu/amd: Take domain->lock for complete attach/detach path
  iommu/amd: Check for busy devices earlier in attach_device()
  iommu/amd: Lock dev_data in attach/detach code paths
  iommu/amd: Lock code paths traversing protection_domain->dev_list

 drivers/iommu/amd_iommu.c       | 166 ++++++++++++++++----------------
 drivers/iommu/amd_iommu_types.h |   4 +-
 2 files changed, 85 insertions(+), 85 deletions(-)

-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH 1/6] iommu/amd: Remove domain->updated
  2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
@ 2019-09-25 13:22 ` Joerg Roedel
  2019-09-25 15:45   ` Sironi, Filippo via iommu
  2019-09-26  6:18   ` Jerry Snitselaar
  2019-09-25 13:22 ` [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock Joerg Roedel
                   ` (5 subsequent siblings)
  6 siblings, 2 replies; 22+ messages in thread
From: Joerg Roedel @ 2019-09-25 13:22 UTC (permalink / raw)
  To: iommu, Joerg Roedel; +Cc: Filippo Sironi, jroedel

From: Joerg Roedel <jroedel@suse.de>

This struct member was used to track whether a domain
change requires updates to the device-table and IOMMU cache
flushes. The problem is, that access to this field is racy
since locking in the common mapping code-paths has been
eliminated.

Move the updated field to the stack to get rid of all
potential races and remove the field from the struct.

Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd_iommu.c       | 49 +++++++++++++++++----------------
 drivers/iommu/amd_iommu_types.h |  1 -
 2 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 7bdce3b10f3d..042854bbc5bc 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1458,10 +1458,11 @@ static void free_pagetable(struct protection_domain *domain)
  * another level increases the size of the address space by 9 bits to a size up
  * to 64 bits.
  */
-static void increase_address_space(struct protection_domain *domain,
+static bool increase_address_space(struct protection_domain *domain,
 				   gfp_t gfp)
 {
 	unsigned long flags;
+	bool ret = false;
 	u64 *pte;
 
 	spin_lock_irqsave(&domain->lock, flags);
@@ -1478,19 +1479,21 @@ static void increase_address_space(struct protection_domain *domain,
 					iommu_virt_to_phys(domain->pt_root));
 	domain->pt_root  = pte;
 	domain->mode    += 1;
-	domain->updated  = true;
+
+	ret = true;
 
 out:
 	spin_unlock_irqrestore(&domain->lock, flags);
 
-	return;
+	return ret;
 }
 
 static u64 *alloc_pte(struct protection_domain *domain,
 		      unsigned long address,
 		      unsigned long page_size,
 		      u64 **pte_page,
-		      gfp_t gfp)
+		      gfp_t gfp,
+		      bool *updated)
 {
 	int level, end_lvl;
 	u64 *pte, *page;
@@ -1498,7 +1501,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
 	BUG_ON(!is_power_of_2(page_size));
 
 	while (address > PM_LEVEL_SIZE(domain->mode))
-		increase_address_space(domain, gfp);
+		*updated = increase_address_space(domain, gfp) || *updated;
 
 	level   = domain->mode - 1;
 	pte     = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
@@ -1530,7 +1533,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
 			for (i = 0; i < count; ++i)
 				cmpxchg64(&lpte[i], __pte, 0ULL);
 
-			domain->updated = true;
+			*updated = true;
 			continue;
 		}
 
@@ -1547,7 +1550,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
 			if (cmpxchg64(pte, __pte, __npte) != __pte)
 				free_page((unsigned long)page);
 			else if (IOMMU_PTE_PRESENT(__pte))
-				domain->updated = true;
+				*updated = true;
 
 			continue;
 		}
@@ -1656,28 +1659,29 @@ static int iommu_map_page(struct protection_domain *dom,
 			  gfp_t gfp)
 {
 	struct page *freelist = NULL;
+	bool updated = false;
 	u64 __pte, *pte;
-	int i, count;
+	int ret, i, count;
 
 	BUG_ON(!IS_ALIGNED(bus_addr, page_size));
 	BUG_ON(!IS_ALIGNED(phys_addr, page_size));
 
+	ret = -EINVAL;
 	if (!(prot & IOMMU_PROT_MASK))
-		return -EINVAL;
+		goto out;
 
 	count = PAGE_SIZE_PTE_COUNT(page_size);
-	pte   = alloc_pte(dom, bus_addr, page_size, NULL, gfp);
+	pte   = alloc_pte(dom, bus_addr, page_size, NULL, gfp, &updated);
 
-	if (!pte) {
-		update_domain(dom);
-		return -ENOMEM;
-	}
+	ret = -ENOMEM;
+	if (!pte)
+		goto out;
 
 	for (i = 0; i < count; ++i)
 		freelist = free_clear_pte(&pte[i], pte[i], freelist);
 
 	if (freelist != NULL)
-		dom->updated = true;
+		updated = true;
 
 	if (count > 1) {
 		__pte = PAGE_SIZE_PTE(__sme_set(phys_addr), page_size);
@@ -1693,12 +1697,16 @@ static int iommu_map_page(struct protection_domain *dom,
 	for (i = 0; i < count; ++i)
 		pte[i] = __pte;
 
-	update_domain(dom);
+	ret = 0;
+
+out:
+	if (updated)
+		update_domain(dom);
 
 	/* Everything flushed out, free pages now */
 	free_page_list(freelist);
 
-	return 0;
+	return ret;
 }
 
 static unsigned long iommu_unmap_page(struct protection_domain *dom,
@@ -2399,15 +2407,10 @@ static void update_device_table(struct protection_domain *domain)
 
 static void update_domain(struct protection_domain *domain)
 {
-	if (!domain->updated)
-		return;
-
 	update_device_table(domain);
 
 	domain_flush_devices(domain);
 	domain_flush_tlb_pde(domain);
-
-	domain->updated = false;
 }
 
 static int dir2prot(enum dma_data_direction direction)
@@ -3333,7 +3336,6 @@ void amd_iommu_domain_direct_map(struct iommu_domain *dom)
 
 	/* Update data structure */
 	domain->mode    = PAGE_MODE_NONE;
-	domain->updated = true;
 
 	/* Make changes visible to IOMMUs */
 	update_domain(domain);
@@ -3379,7 +3381,6 @@ int amd_iommu_domain_enable_v2(struct iommu_domain *dom, int pasids)
 
 	domain->glx      = levels;
 	domain->flags   |= PD_IOMMUV2_MASK;
-	domain->updated  = true;
 
 	update_domain(domain);
 
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 9ac229e92b07..0186501ab971 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -475,7 +475,6 @@ struct protection_domain {
 	int glx;		/* Number of levels for GCR3 table */
 	u64 *gcr3_tbl;		/* Guest CR3 table */
 	unsigned long flags;	/* flags to find out type of domain */
-	bool updated;		/* complete domain flush required */
 	unsigned dev_cnt;	/* devices assigned to this domain */
 	unsigned dev_iommu[MAX_IOMMUS]; /* per-IOMMU reference count */
 };
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock
  2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
  2019-09-25 13:22 ` [PATCH 1/6] iommu/amd: Remove domain->updated Joerg Roedel
@ 2019-09-25 13:22 ` Joerg Roedel
  2019-09-25 15:50   ` Sironi, Filippo via iommu
  2019-09-26  6:24   ` Jerry Snitselaar
  2019-09-25 13:22 ` [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path Joerg Roedel
                   ` (4 subsequent siblings)
  6 siblings, 2 replies; 22+ messages in thread
From: Joerg Roedel @ 2019-09-25 13:22 UTC (permalink / raw)
  To: iommu, Joerg Roedel; +Cc: Filippo Sironi, jroedel

From: Joerg Roedel <jroedel@suse.de>

The lock is not necessary because the device table does not
contain shared state that needs protection. Locking is only
needed on an individual entry basis, and that needs to
happen on the iommu_dev_data level.

Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd_iommu.c | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 042854bbc5bc..37a9c04fc728 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -70,7 +70,6 @@
  */
 #define AMD_IOMMU_PGSIZES	((~0xFFFUL) & ~(2ULL << 38))
 
-static DEFINE_SPINLOCK(amd_iommu_devtable_lock);
 static DEFINE_SPINLOCK(pd_bitmap_lock);
 
 /* List of all available dev_data structures */
@@ -2080,10 +2079,11 @@ static void do_detach(struct iommu_dev_data *dev_data)
 static int __attach_device(struct iommu_dev_data *dev_data,
 			   struct protection_domain *domain)
 {
+	unsigned long flags;
 	int ret;
 
 	/* lock domain */
-	spin_lock(&domain->lock);
+	spin_lock_irqsave(&domain->lock, flags);
 
 	ret = -EBUSY;
 	if (dev_data->domain != NULL)
@@ -2097,7 +2097,7 @@ static int __attach_device(struct iommu_dev_data *dev_data,
 out_unlock:
 
 	/* ready */
-	spin_unlock(&domain->lock);
+	spin_unlock_irqrestore(&domain->lock, flags);
 
 	return ret;
 }
@@ -2181,7 +2181,6 @@ static int attach_device(struct device *dev,
 {
 	struct pci_dev *pdev;
 	struct iommu_dev_data *dev_data;
-	unsigned long flags;
 	int ret;
 
 	dev_data = get_dev_data(dev);
@@ -2209,9 +2208,7 @@ static int attach_device(struct device *dev,
 	}
 
 skip_ats_check:
-	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
 	ret = __attach_device(dev_data, domain);
-	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 
 	/*
 	 * We might boot into a crash-kernel here. The crashed kernel
@@ -2231,14 +2228,15 @@ static int attach_device(struct device *dev,
 static void __detach_device(struct iommu_dev_data *dev_data)
 {
 	struct protection_domain *domain;
+	unsigned long flags;
 
 	domain = dev_data->domain;
 
-	spin_lock(&domain->lock);
+	spin_lock_irqsave(&domain->lock, flags);
 
 	do_detach(dev_data);
 
-	spin_unlock(&domain->lock);
+	spin_unlock_irqrestore(&domain->lock, flags);
 }
 
 /*
@@ -2248,7 +2246,6 @@ static void detach_device(struct device *dev)
 {
 	struct protection_domain *domain;
 	struct iommu_dev_data *dev_data;
-	unsigned long flags;
 
 	dev_data = get_dev_data(dev);
 	domain   = dev_data->domain;
@@ -2262,10 +2259,7 @@ static void detach_device(struct device *dev)
 	if (WARN_ON(!dev_data->domain))
 		return;
 
-	/* lock device table */
-	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
 	__detach_device(dev_data);
-	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 
 	if (!dev_is_pci(dev))
 		return;
@@ -2910,9 +2904,6 @@ int __init amd_iommu_init_dma_ops(void)
 static void cleanup_domain(struct protection_domain *domain)
 {
 	struct iommu_dev_data *entry;
-	unsigned long flags;
-
-	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
 
 	while (!list_empty(&domain->dev_list)) {
 		entry = list_first_entry(&domain->dev_list,
@@ -2920,8 +2911,6 @@ static void cleanup_domain(struct protection_domain *domain)
 		BUG_ON(!entry->domain);
 		__detach_device(entry);
 	}
-
-	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 }
 
 static void protection_domain_free(struct protection_domain *domain)
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path
  2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
  2019-09-25 13:22 ` [PATCH 1/6] iommu/amd: Remove domain->updated Joerg Roedel
  2019-09-25 13:22 ` [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock Joerg Roedel
@ 2019-09-25 13:22 ` Joerg Roedel
  2019-09-25 15:53   ` Sironi, Filippo via iommu
  2019-09-26  6:34   ` Jerry Snitselaar
  2019-09-25 13:22 ` [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device() Joerg Roedel
                   ` (3 subsequent siblings)
  6 siblings, 2 replies; 22+ messages in thread
From: Joerg Roedel @ 2019-09-25 13:22 UTC (permalink / raw)
  To: iommu, Joerg Roedel; +Cc: Filippo Sironi, jroedel

From: Joerg Roedel <jroedel@suse.de>

The code-paths before __attach_device() and __detach_device() are called
also access and modify domain state, so take the domain lock there too.
This allows to get rid of the __detach_device() function.

Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd_iommu.c | 65 ++++++++++++++++-----------------------
 1 file changed, 26 insertions(+), 39 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 37a9c04fc728..2919168577ff 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2079,27 +2079,13 @@ static void do_detach(struct iommu_dev_data *dev_data)
 static int __attach_device(struct iommu_dev_data *dev_data,
 			   struct protection_domain *domain)
 {
-	unsigned long flags;
-	int ret;
-
-	/* lock domain */
-	spin_lock_irqsave(&domain->lock, flags);
-
-	ret = -EBUSY;
 	if (dev_data->domain != NULL)
-		goto out_unlock;
+		return -EBUSY;
 
 	/* Attach alias group root */
 	do_attach(dev_data, domain);
 
-	ret = 0;
-
-out_unlock:
-
-	/* ready */
-	spin_unlock_irqrestore(&domain->lock, flags);
-
-	return ret;
+	return 0;
 }
 
 
@@ -2181,8 +2167,11 @@ static int attach_device(struct device *dev,
 {
 	struct pci_dev *pdev;
 	struct iommu_dev_data *dev_data;
+	unsigned long flags;
 	int ret;
 
+	spin_lock_irqsave(&domain->lock, flags);
+
 	dev_data = get_dev_data(dev);
 
 	if (!dev_is_pci(dev))
@@ -2190,12 +2179,13 @@ static int attach_device(struct device *dev,
 
 	pdev = to_pci_dev(dev);
 	if (domain->flags & PD_IOMMUV2_MASK) {
+		ret = -EINVAL;
 		if (!dev_data->passthrough)
-			return -EINVAL;
+			goto out;
 
 		if (dev_data->iommu_v2) {
 			if (pdev_iommuv2_enable(pdev) != 0)
-				return -EINVAL;
+				goto out;
 
 			dev_data->ats.enabled = true;
 			dev_data->ats.qdep    = pci_ats_queue_depth(pdev);
@@ -2219,24 +2209,10 @@ static int attach_device(struct device *dev,
 
 	domain_flush_complete(domain);
 
-	return ret;
-}
-
-/*
- * Removes a device from a protection domain (unlocked)
- */
-static void __detach_device(struct iommu_dev_data *dev_data)
-{
-	struct protection_domain *domain;
-	unsigned long flags;
-
-	domain = dev_data->domain;
-
-	spin_lock_irqsave(&domain->lock, flags);
-
-	do_detach(dev_data);
-
+out:
 	spin_unlock_irqrestore(&domain->lock, flags);
+
+	return ret;
 }
 
 /*
@@ -2246,10 +2222,13 @@ static void detach_device(struct device *dev)
 {
 	struct protection_domain *domain;
 	struct iommu_dev_data *dev_data;
+	unsigned long flags;
 
 	dev_data = get_dev_data(dev);
 	domain   = dev_data->domain;
 
+	spin_lock_irqsave(&domain->lock, flags);
+
 	/*
 	 * First check if the device is still attached. It might already
 	 * be detached from its domain because the generic
@@ -2257,12 +2236,12 @@ static void detach_device(struct device *dev)
 	 * our alias handling.
 	 */
 	if (WARN_ON(!dev_data->domain))
-		return;
+		goto out;
 
-	__detach_device(dev_data);
+	do_detach(dev_data);
 
 	if (!dev_is_pci(dev))
-		return;
+		goto out;
 
 	if (domain->flags & PD_IOMMUV2_MASK && dev_data->iommu_v2)
 		pdev_iommuv2_disable(to_pci_dev(dev));
@@ -2270,6 +2249,9 @@ static void detach_device(struct device *dev)
 		pci_disable_ats(to_pci_dev(dev));
 
 	dev_data->ats.enabled = false;
+
+out:
+	spin_unlock_irqrestore(&domain->lock, flags);
 }
 
 static int amd_iommu_add_device(struct device *dev)
@@ -2904,13 +2886,18 @@ int __init amd_iommu_init_dma_ops(void)
 static void cleanup_domain(struct protection_domain *domain)
 {
 	struct iommu_dev_data *entry;
+	unsigned long flags;
+
+	spin_lock_irqsave(&domain->lock, flags);
 
 	while (!list_empty(&domain->dev_list)) {
 		entry = list_first_entry(&domain->dev_list,
 					 struct iommu_dev_data, list);
 		BUG_ON(!entry->domain);
-		__detach_device(entry);
+		do_detach(entry);
 	}
+
+	spin_unlock_irqrestore(&domain->lock, flags);
 }
 
 static void protection_domain_free(struct protection_domain *domain)
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device()
  2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
                   ` (2 preceding siblings ...)
  2019-09-25 13:22 ` [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path Joerg Roedel
@ 2019-09-25 13:22 ` Joerg Roedel
  2019-09-25 15:55   ` Sironi, Filippo via iommu
  2019-09-26  6:37   ` Jerry Snitselaar
  2019-09-25 13:22 ` [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths Joerg Roedel
                   ` (2 subsequent siblings)
  6 siblings, 2 replies; 22+ messages in thread
From: Joerg Roedel @ 2019-09-25 13:22 UTC (permalink / raw)
  To: iommu, Joerg Roedel; +Cc: Filippo Sironi, jroedel

From: Joerg Roedel <jroedel@suse.de>

Check early in attach_device whether the device is already attached to a
domain. This also simplifies the code path so that __attach_device() can
be removed.

Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd_iommu.c | 25 +++++++------------------
 1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 2919168577ff..459247c32dc0 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2072,23 +2072,6 @@ static void do_detach(struct iommu_dev_data *dev_data)
 	domain->dev_cnt                 -= 1;
 }
 
-/*
- * If a device is not yet associated with a domain, this function makes the
- * device visible in the domain
- */
-static int __attach_device(struct iommu_dev_data *dev_data,
-			   struct protection_domain *domain)
-{
-	if (dev_data->domain != NULL)
-		return -EBUSY;
-
-	/* Attach alias group root */
-	do_attach(dev_data, domain);
-
-	return 0;
-}
-
-
 static void pdev_iommuv2_disable(struct pci_dev *pdev)
 {
 	pci_disable_ats(pdev);
@@ -2174,6 +2157,10 @@ static int attach_device(struct device *dev,
 
 	dev_data = get_dev_data(dev);
 
+	ret = -EBUSY;
+	if (dev_data->domain != NULL)
+		goto out;
+
 	if (!dev_is_pci(dev))
 		goto skip_ats_check;
 
@@ -2198,7 +2185,9 @@ static int attach_device(struct device *dev,
 	}
 
 skip_ats_check:
-	ret = __attach_device(dev_data, domain);
+	ret = 0;
+
+	do_attach(dev_data, domain);
 
 	/*
 	 * We might boot into a crash-kernel here. The crashed kernel
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths
  2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
                   ` (3 preceding siblings ...)
  2019-09-25 13:22 ` [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device() Joerg Roedel
@ 2019-09-25 13:22 ` Joerg Roedel
  2019-09-25 15:56   ` Sironi, Filippo via iommu
  2019-09-26  6:41   ` Jerry Snitselaar
  2019-09-25 13:23 ` [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list Joerg Roedel
  2019-09-26  0:25 ` [PATCH 0/6] iommu/amd: Locking Fixes Jerry Snitselaar
  6 siblings, 2 replies; 22+ messages in thread
From: Joerg Roedel @ 2019-09-25 13:22 UTC (permalink / raw)
  To: iommu, Joerg Roedel; +Cc: Filippo Sironi, jroedel

From: Joerg Roedel <jroedel@suse.de>

Make sure that attaching a detaching a device can't race against each
other and protect the iommu_dev_data with a spin_lock in these code
paths.

Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd_iommu.c       | 9 +++++++++
 drivers/iommu/amd_iommu_types.h | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 459247c32dc0..bac4e20a5919 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -201,6 +201,7 @@ static struct iommu_dev_data *alloc_dev_data(u16 devid)
 	if (!dev_data)
 		return NULL;
 
+	spin_lock_init(&dev_data->lock);
 	dev_data->devid = devid;
 	ratelimit_default_init(&dev_data->rs);
 
@@ -2157,6 +2158,8 @@ static int attach_device(struct device *dev,
 
 	dev_data = get_dev_data(dev);
 
+	spin_lock(&dev_data->lock);
+
 	ret = -EBUSY;
 	if (dev_data->domain != NULL)
 		goto out;
@@ -2199,6 +2202,8 @@ static int attach_device(struct device *dev,
 	domain_flush_complete(domain);
 
 out:
+	spin_unlock(&dev_data->lock);
+
 	spin_unlock_irqrestore(&domain->lock, flags);
 
 	return ret;
@@ -2218,6 +2223,8 @@ static void detach_device(struct device *dev)
 
 	spin_lock_irqsave(&domain->lock, flags);
 
+	spin_lock(&dev_data->lock);
+
 	/*
 	 * First check if the device is still attached. It might already
 	 * be detached from its domain because the generic
@@ -2240,6 +2247,8 @@ static void detach_device(struct device *dev)
 	dev_data->ats.enabled = false;
 
 out:
+	spin_unlock(&dev_data->lock);
+
 	spin_unlock_irqrestore(&domain->lock, flags);
 }
 
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 0186501ab971..c9c1612d52e0 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -633,6 +633,9 @@ struct devid_map {
  * This struct contains device specific data for the IOMMU
  */
 struct iommu_dev_data {
+	/*Protect against attach/detach races */
+	spinlock_t lock;
+
 	struct list_head list;		  /* For domain->dev_list */
 	struct llist_node dev_data_list;  /* For global dev_data_list */
 	struct protection_domain *domain; /* Domain the device is bound to */
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list
  2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
                   ` (4 preceding siblings ...)
  2019-09-25 13:22 ` [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths Joerg Roedel
@ 2019-09-25 13:23 ` Joerg Roedel
  2019-09-25 15:58   ` Sironi, Filippo via iommu
  2019-09-26  6:48   ` Jerry Snitselaar
  2019-09-26  0:25 ` [PATCH 0/6] iommu/amd: Locking Fixes Jerry Snitselaar
  6 siblings, 2 replies; 22+ messages in thread
From: Joerg Roedel @ 2019-09-25 13:23 UTC (permalink / raw)
  To: iommu, Joerg Roedel; +Cc: Filippo Sironi, jroedel

From: Joerg Roedel <jroedel@suse.de>

The traversing of this list requires protection_domain->lock to be taken
to avoid nasty races with attach/detach code. Make sure the lock is held
on all code-paths traversing this list.

Reported-by: Filippo Sironi <sironi@amazon.de>
Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd_iommu.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index bac4e20a5919..9c26976a0f99 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1334,8 +1334,12 @@ static void domain_flush_np_cache(struct protection_domain *domain,
 		dma_addr_t iova, size_t size)
 {
 	if (unlikely(amd_iommu_np_cache)) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&domain->lock, flags);
 		domain_flush_pages(domain, iova, size);
 		domain_flush_complete(domain);
+		spin_unlock_irqrestore(&domain->lock, flags);
 	}
 }
 
@@ -1700,8 +1704,13 @@ static int iommu_map_page(struct protection_domain *dom,
 	ret = 0;
 
 out:
-	if (updated)
+	if (updated) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&dom->lock, flags);
 		update_domain(dom);
+		spin_unlock_irqrestore(&dom->lock, flags);
+	}
 
 	/* Everything flushed out, free pages now */
 	free_page_list(freelist);
@@ -1857,8 +1866,12 @@ static void free_gcr3_table(struct protection_domain *domain)
 
 static void dma_ops_domain_flush_tlb(struct dma_ops_domain *dom)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(&dom->domain.lock, flags);
 	domain_flush_tlb(&dom->domain);
 	domain_flush_complete(&dom->domain);
+	spin_unlock_irqrestore(&dom->domain.lock, flags);
 }
 
 static void iova_domain_flush_tlb(struct iova_domain *iovad)
@@ -2414,6 +2427,7 @@ static dma_addr_t __map_single(struct device *dev,
 {
 	dma_addr_t offset = paddr & ~PAGE_MASK;
 	dma_addr_t address, start, ret;
+	unsigned long flags;
 	unsigned int pages;
 	int prot = 0;
 	int i;
@@ -2451,8 +2465,10 @@ static dma_addr_t __map_single(struct device *dev,
 		iommu_unmap_page(&dma_dom->domain, start, PAGE_SIZE);
 	}
 
+	spin_lock_irqsave(&dma_dom->domain.lock, flags);
 	domain_flush_tlb(&dma_dom->domain);
 	domain_flush_complete(&dma_dom->domain);
+	spin_unlock_irqrestore(&dma_dom->domain.lock, flags);
 
 	dma_ops_free_iova(dma_dom, address, pages);
 
@@ -2481,8 +2497,12 @@ static void __unmap_single(struct dma_ops_domain *dma_dom,
 	}
 
 	if (amd_iommu_unmap_flush) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&dma_dom->domain.lock, flags);
 		domain_flush_tlb(&dma_dom->domain);
 		domain_flush_complete(&dma_dom->domain);
+		spin_unlock_irqrestore(&dma_dom->domain.lock, flags);
 		dma_ops_free_iova(dma_dom, dma_addr, pages);
 	} else {
 		pages = __roundup_pow_of_two(pages);
@@ -3246,9 +3266,12 @@ static bool amd_iommu_is_attach_deferred(struct iommu_domain *domain,
 static void amd_iommu_flush_iotlb_all(struct iommu_domain *domain)
 {
 	struct protection_domain *dom = to_pdomain(domain);
+	unsigned long flags;
 
+	spin_lock_irqsave(&dom->lock, flags);
 	domain_flush_tlb_pde(dom);
 	domain_flush_complete(dom);
+	spin_unlock_irqrestore(&dom->lock, flags);
 }
 
 static void amd_iommu_iotlb_sync(struct iommu_domain *domain,
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 1/6] iommu/amd: Remove domain->updated
  2019-09-25 13:22 ` [PATCH 1/6] iommu/amd: Remove domain->updated Joerg Roedel
@ 2019-09-25 15:45   ` Sironi, Filippo via iommu
  2019-09-26  6:18   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Sironi, Filippo via iommu @ 2019-09-25 15:45 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: iommu, jroedel



> On 25. Sep 2019, at 06:22, Joerg Roedel <joro@8bytes.org> wrote:
> 
> From: Joerg Roedel <jroedel@suse.de>
> 
> This struct member was used to track whether a domain
> change requires updates to the device-table and IOMMU cache
> flushes. The problem is, that access to this field is racy
> since locking in the common mapping code-paths has been
> eliminated.
> 
> Move the updated field to the stack to get rid of all
> potential races and remove the field from the struct.
> 
> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
> drivers/iommu/amd_iommu.c       | 49 +++++++++++++++++----------------
> drivers/iommu/amd_iommu_types.h |  1 -
> 2 files changed, 25 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 7bdce3b10f3d..042854bbc5bc 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -1458,10 +1458,11 @@ static void free_pagetable(struct protection_domain *domain)
>  * another level increases the size of the address space by 9 bits to a size up
>  * to 64 bits.
>  */
> -static void increase_address_space(struct protection_domain *domain,
> +static bool increase_address_space(struct protection_domain *domain,
> 				   gfp_t gfp)
> {
> 	unsigned long flags;
> +	bool ret = false;
> 	u64 *pte;
> 
> 	spin_lock_irqsave(&domain->lock, flags);
> @@ -1478,19 +1479,21 @@ static void increase_address_space(struct protection_domain *domain,
> 					iommu_virt_to_phys(domain->pt_root));
> 	domain->pt_root  = pte;
> 	domain->mode    += 1;
> -	domain->updated  = true;
> +
> +	ret = true;
> 
> out:
> 	spin_unlock_irqrestore(&domain->lock, flags);
> 
> -	return;
> +	return ret;
> }
> 
> static u64 *alloc_pte(struct protection_domain *domain,
> 		      unsigned long address,
> 		      unsigned long page_size,
> 		      u64 **pte_page,
> -		      gfp_t gfp)
> +		      gfp_t gfp,
> +		      bool *updated)
> {
> 	int level, end_lvl;
> 	u64 *pte, *page;
> @@ -1498,7 +1501,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
> 	BUG_ON(!is_power_of_2(page_size));
> 
> 	while (address > PM_LEVEL_SIZE(domain->mode))
> -		increase_address_space(domain, gfp);
> +		*updated = increase_address_space(domain, gfp) || *updated;
> 
> 	level   = domain->mode - 1;
> 	pte     = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
> @@ -1530,7 +1533,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
> 			for (i = 0; i < count; ++i)
> 				cmpxchg64(&lpte[i], __pte, 0ULL);
> 
> -			domain->updated = true;
> +			*updated = true;
> 			continue;
> 		}
> 
> @@ -1547,7 +1550,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
> 			if (cmpxchg64(pte, __pte, __npte) != __pte)
> 				free_page((unsigned long)page);
> 			else if (IOMMU_PTE_PRESENT(__pte))
> -				domain->updated = true;
> +				*updated = true;
> 
> 			continue;
> 		}
> @@ -1656,28 +1659,29 @@ static int iommu_map_page(struct protection_domain *dom,
> 			  gfp_t gfp)
> {
> 	struct page *freelist = NULL;
> +	bool updated = false;
> 	u64 __pte, *pte;
> -	int i, count;
> +	int ret, i, count;
> 
> 	BUG_ON(!IS_ALIGNED(bus_addr, page_size));
> 	BUG_ON(!IS_ALIGNED(phys_addr, page_size));
> 
> +	ret = -EINVAL;
> 	if (!(prot & IOMMU_PROT_MASK))
> -		return -EINVAL;
> +		goto out;
> 
> 	count = PAGE_SIZE_PTE_COUNT(page_size);
> -	pte   = alloc_pte(dom, bus_addr, page_size, NULL, gfp);
> +	pte   = alloc_pte(dom, bus_addr, page_size, NULL, gfp, &updated);
> 
> -	if (!pte) {
> -		update_domain(dom);
> -		return -ENOMEM;
> -	}
> +	ret = -ENOMEM;
> +	if (!pte)
> +		goto out;
> 
> 	for (i = 0; i < count; ++i)
> 		freelist = free_clear_pte(&pte[i], pte[i], freelist);
> 
> 	if (freelist != NULL)
> -		dom->updated = true;
> +		updated = true;
> 
> 	if (count > 1) {
> 		__pte = PAGE_SIZE_PTE(__sme_set(phys_addr), page_size);
> @@ -1693,12 +1697,16 @@ static int iommu_map_page(struct protection_domain *dom,
> 	for (i = 0; i < count; ++i)
> 		pte[i] = __pte;
> 
> -	update_domain(dom);
> +	ret = 0;
> +
> +out:
> +	if (updated)
> +		update_domain(dom);
> 
> 	/* Everything flushed out, free pages now */
> 	free_page_list(freelist);
> 
> -	return 0;
> +	return ret;
> }
> 
> static unsigned long iommu_unmap_page(struct protection_domain *dom,
> @@ -2399,15 +2407,10 @@ static void update_device_table(struct protection_domain *domain)
> 
> static void update_domain(struct protection_domain *domain)
> {
> -	if (!domain->updated)
> -		return;
> -
> 	update_device_table(domain);
> 
> 	domain_flush_devices(domain);
> 	domain_flush_tlb_pde(domain);
> -
> -	domain->updated = false;
> }
> 
> static int dir2prot(enum dma_data_direction direction)
> @@ -3333,7 +3336,6 @@ void amd_iommu_domain_direct_map(struct iommu_domain *dom)
> 
> 	/* Update data structure */
> 	domain->mode    = PAGE_MODE_NONE;
> -	domain->updated = true;
> 
> 	/* Make changes visible to IOMMUs */
> 	update_domain(domain);
> @@ -3379,7 +3381,6 @@ int amd_iommu_domain_enable_v2(struct iommu_domain *dom, int pasids)
> 
> 	domain->glx      = levels;
> 	domain->flags   |= PD_IOMMUV2_MASK;
> -	domain->updated  = true;
> 
> 	update_domain(domain);
> 
> diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
> index 9ac229e92b07..0186501ab971 100644
> --- a/drivers/iommu/amd_iommu_types.h
> +++ b/drivers/iommu/amd_iommu_types.h
> @@ -475,7 +475,6 @@ struct protection_domain {
> 	int glx;		/* Number of levels for GCR3 table */
> 	u64 *gcr3_tbl;		/* Guest CR3 table */
> 	unsigned long flags;	/* flags to find out type of domain */
> -	bool updated;		/* complete domain flush required */
> 	unsigned dev_cnt;	/* devices assigned to this domain */
> 	unsigned dev_iommu[MAX_IOMMUS]; /* per-IOMMU reference count */
> };
> -- 
> 2.17.1
> 

Reviewed-by: Filippo Sironi <sironi@amazon.de>



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock
  2019-09-25 13:22 ` [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock Joerg Roedel
@ 2019-09-25 15:50   ` Sironi, Filippo via iommu
  2019-09-25 15:52     ` Sironi, Filippo via iommu
  2019-09-26  6:24   ` Jerry Snitselaar
  1 sibling, 1 reply; 22+ messages in thread
From: Sironi, Filippo via iommu @ 2019-09-25 15:50 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: iommu, jroedel



> On 25. Sep 2019, at 06:22, Joerg Roedel <joro@8bytes.org> wrote:
> 
> From: Joerg Roedel <jroedel@suse.de>
> 
> The lock is not necessary because the device table does not
> contain shared state that needs protection. Locking is only
> needed on an individual entry basis, and that needs to
> happen on the iommu_dev_data level.
> 
> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
> drivers/iommu/amd_iommu.c | 23 ++++++-----------------
> 1 file changed, 6 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 042854bbc5bc..37a9c04fc728 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -70,7 +70,6 @@
>  */
> #define AMD_IOMMU_PGSIZES	((~0xFFFUL) & ~(2ULL << 38))
> 
> -static DEFINE_SPINLOCK(amd_iommu_devtable_lock);
> static DEFINE_SPINLOCK(pd_bitmap_lock);
> 
> /* List of all available dev_data structures */
> @@ -2080,10 +2079,11 @@ static void do_detach(struct iommu_dev_data *dev_data)
> static int __attach_device(struct iommu_dev_data *dev_data,
> 			   struct protection_domain *domain)
> {
> +	unsigned long flags;
> 	int ret;
> 
> 	/* lock domain */
> -	spin_lock(&domain->lock);
> +	spin_lock_irqsave(&domain->lock, flags);
> 
> 	ret = -EBUSY;
> 	if (dev_data->domain != NULL)
> @@ -2097,7 +2097,7 @@ static int __attach_device(struct iommu_dev_data *dev_data,
> out_unlock:
> 
> 	/* ready */
> -	spin_unlock(&domain->lock);
> +	spin_unlock_irqrestore(&domain->lock, flags);
> 
> 	return ret;
> }
> @@ -2181,7 +2181,6 @@ static int attach_device(struct device *dev,
> {
> 	struct pci_dev *pdev;
> 	struct iommu_dev_data *dev_data;
> -	unsigned long flags;
> 	int ret;
> 
> 	dev_data = get_dev_data(dev);
> @@ -2209,9 +2208,7 @@ static int attach_device(struct device *dev,
> 	}
> 
> skip_ats_check:
> -	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
> 	ret = __attach_device(dev_data, domain);
> -	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
> 
> 	/*
> 	 * We might boot into a crash-kernel here. The crashed kernel
> @@ -2231,14 +2228,15 @@ static int attach_device(struct device *dev,
> static void __detach_device(struct iommu_dev_data *dev_data)
> {
> 	struct protection_domain *domain;
> +	unsigned long flags;
> 
> 	domain = dev_data->domain;
> 
> -	spin_lock(&domain->lock);
> +	spin_lock_irqsave(&domain->lock, flags);
> 
> 	do_detach(dev_data);
> 
> -	spin_unlock(&domain->lock);
> +	spin_unlock_irqrestore(&domain->lock, flags);
> }
> 
> /*
> @@ -2248,7 +2246,6 @@ static void detach_device(struct device *dev)
> {
> 	struct protection_domain *domain;
> 	struct iommu_dev_data *dev_data;
> -	unsigned long flags;
> 
> 	dev_data = get_dev_data(dev);
> 	domain   = dev_data->domain;
> @@ -2262,10 +2259,7 @@ static void detach_device(struct device *dev)
> 	if (WARN_ON(!dev_data->domain))
> 		return;
> 
> -	/* lock device table */
> -	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
> 	__detach_device(dev_data);
> -	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
> 
> 	if (!dev_is_pci(dev))
> 		return;
> @@ -2910,9 +2904,6 @@ int __init amd_iommu_init_dma_ops(void)
> static void cleanup_domain(struct protection_domain *domain)
> {
> 	struct iommu_dev_data *entry;
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
> 
> 	while (!list_empty(&domain->dev_list)) {
> 		entry = list_first_entry(&domain->dev_list,
> @@ -2920,8 +2911,6 @@ static void cleanup_domain(struct protection_domain *domain)
> 		BUG_ON(!entry->domain);
> 		__detach_device(entry);
> 	}
> -
> -	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
> }

I'm guessing that it is free not to take the domain lock in cleanup_domain
since this is called when free-ing the domain.  Right?

> static void protection_domain_free(struct protection_domain *domain)
> -- 
> 2.17.1
> 




Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock
  2019-09-25 15:50   ` Sironi, Filippo via iommu
@ 2019-09-25 15:52     ` Sironi, Filippo via iommu
  0 siblings, 0 replies; 22+ messages in thread
From: Sironi, Filippo via iommu @ 2019-09-25 15:52 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: iommu, jroedel



> On 25. Sep 2019, at 08:50, Sironi, Filippo <sironi@amazon.de> wrote:
> 
> 
> 
>> On 25. Sep 2019, at 06:22, Joerg Roedel <joro@8bytes.org> wrote:
>> 
>> From: Joerg Roedel <jroedel@suse.de>
>> 
>> The lock is not necessary because the device table does not
>> contain shared state that needs protection. Locking is only
>> needed on an individual entry basis, and that needs to
>> happen on the iommu_dev_data level.
>> 
>> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
>> Signed-off-by: Joerg Roedel <jroedel@suse.de>
>> ---
>> drivers/iommu/amd_iommu.c | 23 ++++++-----------------
>> 1 file changed, 6 insertions(+), 17 deletions(-)
>> 
>> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>> index 042854bbc5bc..37a9c04fc728 100644
>> --- a/drivers/iommu/amd_iommu.c
>> +++ b/drivers/iommu/amd_iommu.c
>> @@ -70,7 +70,6 @@
>> */
>> #define AMD_IOMMU_PGSIZES	((~0xFFFUL) & ~(2ULL << 38))
>> 
>> -static DEFINE_SPINLOCK(amd_iommu_devtable_lock);
>> static DEFINE_SPINLOCK(pd_bitmap_lock);
>> 
>> /* List of all available dev_data structures */
>> @@ -2080,10 +2079,11 @@ static void do_detach(struct iommu_dev_data *dev_data)
>> static int __attach_device(struct iommu_dev_data *dev_data,
>> 			   struct protection_domain *domain)
>> {
>> +	unsigned long flags;
>> 	int ret;
>> 
>> 	/* lock domain */
>> -	spin_lock(&domain->lock);
>> +	spin_lock_irqsave(&domain->lock, flags);
>> 
>> 	ret = -EBUSY;
>> 	if (dev_data->domain != NULL)
>> @@ -2097,7 +2097,7 @@ static int __attach_device(struct iommu_dev_data *dev_data,
>> out_unlock:
>> 
>> 	/* ready */
>> -	spin_unlock(&domain->lock);
>> +	spin_unlock_irqrestore(&domain->lock, flags);
>> 
>> 	return ret;
>> }
>> @@ -2181,7 +2181,6 @@ static int attach_device(struct device *dev,
>> {
>> 	struct pci_dev *pdev;
>> 	struct iommu_dev_data *dev_data;
>> -	unsigned long flags;
>> 	int ret;
>> 
>> 	dev_data = get_dev_data(dev);
>> @@ -2209,9 +2208,7 @@ static int attach_device(struct device *dev,
>> 	}
>> 
>> skip_ats_check:
>> -	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
>> 	ret = __attach_device(dev_data, domain);
>> -	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
>> 
>> 	/*
>> 	 * We might boot into a crash-kernel here. The crashed kernel
>> @@ -2231,14 +2228,15 @@ static int attach_device(struct device *dev,
>> static void __detach_device(struct iommu_dev_data *dev_data)
>> {
>> 	struct protection_domain *domain;
>> +	unsigned long flags;
>> 
>> 	domain = dev_data->domain;
>> 
>> -	spin_lock(&domain->lock);
>> +	spin_lock_irqsave(&domain->lock, flags);
>> 
>> 	do_detach(dev_data);
>> 
>> -	spin_unlock(&domain->lock);
>> +	spin_unlock_irqrestore(&domain->lock, flags);
>> }
>> 
>> /*
>> @@ -2248,7 +2246,6 @@ static void detach_device(struct device *dev)
>> {
>> 	struct protection_domain *domain;
>> 	struct iommu_dev_data *dev_data;
>> -	unsigned long flags;
>> 
>> 	dev_data = get_dev_data(dev);
>> 	domain   = dev_data->domain;
>> @@ -2262,10 +2259,7 @@ static void detach_device(struct device *dev)
>> 	if (WARN_ON(!dev_data->domain))
>> 		return;
>> 
>> -	/* lock device table */
>> -	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
>> 	__detach_device(dev_data);
>> -	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
>> 
>> 	if (!dev_is_pci(dev))
>> 		return;
>> @@ -2910,9 +2904,6 @@ int __init amd_iommu_init_dma_ops(void)
>> static void cleanup_domain(struct protection_domain *domain)
>> {
>> 	struct iommu_dev_data *entry;
>> -	unsigned long flags;
>> -
>> -	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
>> 
>> 	while (!list_empty(&domain->dev_list)) {
>> 		entry = list_first_entry(&domain->dev_list,
>> @@ -2920,8 +2911,6 @@ static void cleanup_domain(struct protection_domain *domain)
>> 		BUG_ON(!entry->domain);
>> 		__detach_device(entry);
>> 	}
>> -
>> -	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
>> }
> 
> I'm guessing that it is free not to take the domain lock in cleanup_domain
> since this is called when free-ing the domain.  Right?

My guess was wrong but I see that you've fixed this in patch 3/6.

>> static void protection_domain_free(struct protection_domain *domain)
>> -- 
>> 2.17.1

Reviewed-by: Filippo Sironi <sironi@amazon.de>



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path
  2019-09-25 13:22 ` [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path Joerg Roedel
@ 2019-09-25 15:53   ` Sironi, Filippo via iommu
  2019-09-26  6:34   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Sironi, Filippo via iommu @ 2019-09-25 15:53 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi via iommu, jroedel



> On 25. Sep 2019, at 06:22, Joerg Roedel <joro@8bytes.org> wrote:
> 
> From: Joerg Roedel <jroedel@suse.de>
> 
> The code-paths before __attach_device() and __detach_device() are called
> also access and modify domain state, so take the domain lock there too.
> This allows to get rid of the __detach_device() function.
> 
> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
> drivers/iommu/amd_iommu.c | 65 ++++++++++++++++-----------------------
> 1 file changed, 26 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 37a9c04fc728..2919168577ff 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -2079,27 +2079,13 @@ static void do_detach(struct iommu_dev_data *dev_data)
> static int __attach_device(struct iommu_dev_data *dev_data,
> 			   struct protection_domain *domain)
> {
> -	unsigned long flags;
> -	int ret;
> -
> -	/* lock domain */
> -	spin_lock_irqsave(&domain->lock, flags);
> -
> -	ret = -EBUSY;
> 	if (dev_data->domain != NULL)
> -		goto out_unlock;
> +		return -EBUSY;
> 
> 	/* Attach alias group root */
> 	do_attach(dev_data, domain);
> 
> -	ret = 0;
> -
> -out_unlock:
> -
> -	/* ready */
> -	spin_unlock_irqrestore(&domain->lock, flags);
> -
> -	return ret;
> +	return 0;
> }
> 
> 
> @@ -2181,8 +2167,11 @@ static int attach_device(struct device *dev,
> {
> 	struct pci_dev *pdev;
> 	struct iommu_dev_data *dev_data;
> +	unsigned long flags;
> 	int ret;
> 
> +	spin_lock_irqsave(&domain->lock, flags);
> +
> 	dev_data = get_dev_data(dev);
> 
> 	if (!dev_is_pci(dev))
> @@ -2190,12 +2179,13 @@ static int attach_device(struct device *dev,
> 
> 	pdev = to_pci_dev(dev);
> 	if (domain->flags & PD_IOMMUV2_MASK) {
> +		ret = -EINVAL;
> 		if (!dev_data->passthrough)
> -			return -EINVAL;
> +			goto out;
> 
> 		if (dev_data->iommu_v2) {
> 			if (pdev_iommuv2_enable(pdev) != 0)
> -				return -EINVAL;
> +				goto out;
> 
> 			dev_data->ats.enabled = true;
> 			dev_data->ats.qdep    = pci_ats_queue_depth(pdev);
> @@ -2219,24 +2209,10 @@ static int attach_device(struct device *dev,
> 
> 	domain_flush_complete(domain);
> 
> -	return ret;
> -}
> -
> -/*
> - * Removes a device from a protection domain (unlocked)
> - */
> -static void __detach_device(struct iommu_dev_data *dev_data)
> -{
> -	struct protection_domain *domain;
> -	unsigned long flags;
> -
> -	domain = dev_data->domain;
> -
> -	spin_lock_irqsave(&domain->lock, flags);
> -
> -	do_detach(dev_data);
> -
> +out:
> 	spin_unlock_irqrestore(&domain->lock, flags);
> +
> +	return ret;
> }
> 
> /*
> @@ -2246,10 +2222,13 @@ static void detach_device(struct device *dev)
> {
> 	struct protection_domain *domain;
> 	struct iommu_dev_data *dev_data;
> +	unsigned long flags;
> 
> 	dev_data = get_dev_data(dev);
> 	domain   = dev_data->domain;
> 
> +	spin_lock_irqsave(&domain->lock, flags);
> +
> 	/*
> 	 * First check if the device is still attached. It might already
> 	 * be detached from its domain because the generic
> @@ -2257,12 +2236,12 @@ static void detach_device(struct device *dev)
> 	 * our alias handling.
> 	 */
> 	if (WARN_ON(!dev_data->domain))
> -		return;
> +		goto out;
> 
> -	__detach_device(dev_data);
> +	do_detach(dev_data);
> 
> 	if (!dev_is_pci(dev))
> -		return;
> +		goto out;
> 
> 	if (domain->flags & PD_IOMMUV2_MASK && dev_data->iommu_v2)
> 		pdev_iommuv2_disable(to_pci_dev(dev));
> @@ -2270,6 +2249,9 @@ static void detach_device(struct device *dev)
> 		pci_disable_ats(to_pci_dev(dev));
> 
> 	dev_data->ats.enabled = false;
> +
> +out:
> +	spin_unlock_irqrestore(&domain->lock, flags);
> }
> 
> static int amd_iommu_add_device(struct device *dev)
> @@ -2904,13 +2886,18 @@ int __init amd_iommu_init_dma_ops(void)
> static void cleanup_domain(struct protection_domain *domain)
> {
> 	struct iommu_dev_data *entry;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&domain->lock, flags);
> 
> 	while (!list_empty(&domain->dev_list)) {
> 		entry = list_first_entry(&domain->dev_list,
> 					 struct iommu_dev_data, list);
> 		BUG_ON(!entry->domain);
> -		__detach_device(entry);
> +		do_detach(entry);
> 	}
> +
> +	spin_unlock_irqrestore(&domain->lock, flags);
> }
> 
> static void protection_domain_free(struct protection_domain *domain)
> -- 
> 2.17.1
> 

Reviewed-by: Filippo Sironi <sironi@amazon.de>



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device()
  2019-09-25 13:22 ` [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device() Joerg Roedel
@ 2019-09-25 15:55   ` Sironi, Filippo via iommu
  2019-09-26  6:37   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Sironi, Filippo via iommu @ 2019-09-25 15:55 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: iommu, jroedel



> On 25. Sep 2019, at 06:22, Joerg Roedel <joro@8bytes.org> wrote:
> 
> From: Joerg Roedel <jroedel@suse.de>
> 
> Check early in attach_device whether the device is already attached to a
> domain. This also simplifies the code path so that __attach_device() can
> be removed.
> 
> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
> drivers/iommu/amd_iommu.c | 25 +++++++------------------
> 1 file changed, 7 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 2919168577ff..459247c32dc0 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -2072,23 +2072,6 @@ static void do_detach(struct iommu_dev_data *dev_data)
> 	domain->dev_cnt                 -= 1;
> }
> 
> -/*
> - * If a device is not yet associated with a domain, this function makes the
> - * device visible in the domain
> - */
> -static int __attach_device(struct iommu_dev_data *dev_data,
> -			   struct protection_domain *domain)
> -{
> -	if (dev_data->domain != NULL)
> -		return -EBUSY;
> -
> -	/* Attach alias group root */
> -	do_attach(dev_data, domain);
> -
> -	return 0;
> -}
> -
> -
> static void pdev_iommuv2_disable(struct pci_dev *pdev)
> {
> 	pci_disable_ats(pdev);
> @@ -2174,6 +2157,10 @@ static int attach_device(struct device *dev,
> 
> 	dev_data = get_dev_data(dev);
> 
> +	ret = -EBUSY;
> +	if (dev_data->domain != NULL)
> +		goto out;
> +
> 	if (!dev_is_pci(dev))
> 		goto skip_ats_check;
> 
> @@ -2198,7 +2185,9 @@ static int attach_device(struct device *dev,
> 	}
> 
> skip_ats_check:
> -	ret = __attach_device(dev_data, domain);
> +	ret = 0;
> +
> +	do_attach(dev_data, domain);
> 
> 	/*
> 	 * We might boot into a crash-kernel here. The crashed kernel
> -- 
> 2.17.1
> 

Reviewed-by: Filippo Sironi <sironi@amazon.de>



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths
  2019-09-25 13:22 ` [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths Joerg Roedel
@ 2019-09-25 15:56   ` Sironi, Filippo via iommu
  2019-09-26  6:41   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Sironi, Filippo via iommu @ 2019-09-25 15:56 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi via iommu, jroedel



> On 25. Sep 2019, at 06:22, Joerg Roedel <joro@8bytes.org> wrote:
> 
> From: Joerg Roedel <jroedel@suse.de>
> 
> Make sure that attaching a detaching a device can't race against each
> other and protect the iommu_dev_data with a spin_lock in these code
> paths.
> 
> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
> drivers/iommu/amd_iommu.c       | 9 +++++++++
> drivers/iommu/amd_iommu_types.h | 3 +++
> 2 files changed, 12 insertions(+)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 459247c32dc0..bac4e20a5919 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -201,6 +201,7 @@ static struct iommu_dev_data *alloc_dev_data(u16 devid)
> 	if (!dev_data)
> 		return NULL;
> 
> +	spin_lock_init(&dev_data->lock);
> 	dev_data->devid = devid;
> 	ratelimit_default_init(&dev_data->rs);
> 
> @@ -2157,6 +2158,8 @@ static int attach_device(struct device *dev,
> 
> 	dev_data = get_dev_data(dev);
> 
> +	spin_lock(&dev_data->lock);
> +
> 	ret = -EBUSY;
> 	if (dev_data->domain != NULL)
> 		goto out;
> @@ -2199,6 +2202,8 @@ static int attach_device(struct device *dev,
> 	domain_flush_complete(domain);
> 
> out:
> +	spin_unlock(&dev_data->lock);
> +
> 	spin_unlock_irqrestore(&domain->lock, flags);
> 
> 	return ret;
> @@ -2218,6 +2223,8 @@ static void detach_device(struct device *dev)
> 
> 	spin_lock_irqsave(&domain->lock, flags);
> 
> +	spin_lock(&dev_data->lock);
> +
> 	/*
> 	 * First check if the device is still attached. It might already
> 	 * be detached from its domain because the generic
> @@ -2240,6 +2247,8 @@ static void detach_device(struct device *dev)
> 	dev_data->ats.enabled = false;
> 
> out:
> +	spin_unlock(&dev_data->lock);
> +
> 	spin_unlock_irqrestore(&domain->lock, flags);
> }
> 
> diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
> index 0186501ab971..c9c1612d52e0 100644
> --- a/drivers/iommu/amd_iommu_types.h
> +++ b/drivers/iommu/amd_iommu_types.h
> @@ -633,6 +633,9 @@ struct devid_map {
>  * This struct contains device specific data for the IOMMU
>  */
> struct iommu_dev_data {
> +	/*Protect against attach/detach races */
> +	spinlock_t lock;
> +
> 	struct list_head list;		  /* For domain->dev_list */
> 	struct llist_node dev_data_list;  /* For global dev_data_list */
> 	struct protection_domain *domain; /* Domain the device is bound to */
> -- 
> 2.17.1
> 

Reviewed-by: Filippo Sironi <sironi@amazon.de>



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list
  2019-09-25 13:23 ` [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list Joerg Roedel
@ 2019-09-25 15:58   ` Sironi, Filippo via iommu
  2019-09-26  6:48   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Sironi, Filippo via iommu @ 2019-09-25 15:58 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: iommu, jroedel



> On 25. Sep 2019, at 06:23, Joerg Roedel <joro@8bytes.org> wrote:
> 
> From: Joerg Roedel <jroedel@suse.de>
> 
> The traversing of this list requires protection_domain->lock to be taken
> to avoid nasty races with attach/detach code. Make sure the lock is held
> on all code-paths traversing this list.
> 
> Reported-by: Filippo Sironi <sironi@amazon.de>
> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
> drivers/iommu/amd_iommu.c | 25 ++++++++++++++++++++++++-
> 1 file changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index bac4e20a5919..9c26976a0f99 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -1334,8 +1334,12 @@ static void domain_flush_np_cache(struct protection_domain *domain,
> 		dma_addr_t iova, size_t size)
> {
> 	if (unlikely(amd_iommu_np_cache)) {
> +		unsigned long flags;
> +
> +		spin_lock_irqsave(&domain->lock, flags);
> 		domain_flush_pages(domain, iova, size);
> 		domain_flush_complete(domain);
> +		spin_unlock_irqrestore(&domain->lock, flags);
> 	}
> }
> 
> @@ -1700,8 +1704,13 @@ static int iommu_map_page(struct protection_domain *dom,
> 	ret = 0;
> 
> out:
> -	if (updated)
> +	if (updated) {
> +		unsigned long flags;
> +
> +		spin_lock_irqsave(&dom->lock, flags);
> 		update_domain(dom);
> +		spin_unlock_irqrestore(&dom->lock, flags);
> +	}
> 
> 	/* Everything flushed out, free pages now */
> 	free_page_list(freelist);
> @@ -1857,8 +1866,12 @@ static void free_gcr3_table(struct protection_domain *domain)
> 
> static void dma_ops_domain_flush_tlb(struct dma_ops_domain *dom)
> {
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&dom->domain.lock, flags);
> 	domain_flush_tlb(&dom->domain);
> 	domain_flush_complete(&dom->domain);
> +	spin_unlock_irqrestore(&dom->domain.lock, flags);
> }
> 
> static void iova_domain_flush_tlb(struct iova_domain *iovad)
> @@ -2414,6 +2427,7 @@ static dma_addr_t __map_single(struct device *dev,
> {
> 	dma_addr_t offset = paddr & ~PAGE_MASK;
> 	dma_addr_t address, start, ret;
> +	unsigned long flags;
> 	unsigned int pages;
> 	int prot = 0;
> 	int i;
> @@ -2451,8 +2465,10 @@ static dma_addr_t __map_single(struct device *dev,
> 		iommu_unmap_page(&dma_dom->domain, start, PAGE_SIZE);
> 	}
> 
> +	spin_lock_irqsave(&dma_dom->domain.lock, flags);
> 	domain_flush_tlb(&dma_dom->domain);
> 	domain_flush_complete(&dma_dom->domain);
> +	spin_unlock_irqrestore(&dma_dom->domain.lock, flags);
> 
> 	dma_ops_free_iova(dma_dom, address, pages);
> 
> @@ -2481,8 +2497,12 @@ static void __unmap_single(struct dma_ops_domain *dma_dom,
> 	}
> 
> 	if (amd_iommu_unmap_flush) {
> +		unsigned long flags;
> +
> +		spin_lock_irqsave(&dma_dom->domain.lock, flags);
> 		domain_flush_tlb(&dma_dom->domain);
> 		domain_flush_complete(&dma_dom->domain);
> +		spin_unlock_irqrestore(&dma_dom->domain.lock, flags);
> 		dma_ops_free_iova(dma_dom, dma_addr, pages);
> 	} else {
> 		pages = __roundup_pow_of_two(pages);
> @@ -3246,9 +3266,12 @@ static bool amd_iommu_is_attach_deferred(struct iommu_domain *domain,
> static void amd_iommu_flush_iotlb_all(struct iommu_domain *domain)
> {
> 	struct protection_domain *dom = to_pdomain(domain);
> +	unsigned long flags;
> 
> +	spin_lock_irqsave(&dom->lock, flags);
> 	domain_flush_tlb_pde(dom);
> 	domain_flush_complete(dom);
> +	spin_unlock_irqrestore(&dom->lock, flags);
> }
> 
> static void amd_iommu_iotlb_sync(struct iommu_domain *domain,
> -- 
> 2.17.1
> 

Reviewed-by: Filippo Sironi <sironi@amazon.de>



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 0/6] iommu/amd: Locking Fixes
  2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
                   ` (5 preceding siblings ...)
  2019-09-25 13:23 ` [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list Joerg Roedel
@ 2019-09-26  0:25 ` Jerry Snitselaar
  2019-09-26  5:46   ` Joerg Roedel
  6 siblings, 1 reply; 22+ messages in thread
From: Jerry Snitselaar @ 2019-09-26  0:25 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi, iommu, jroedel

On Wed Sep 25 19, Joerg Roedel wrote:
>Hi,
>
>here are a couple of fixes for the amd iommu driver to fix a
>few locking issues around protection-domains. Main problem
>was that some traversals of ->dev_list were not locked in
>any form, causing potential race conditions.
>
>But there are more issues fixed here, for example the racy
>access to protection_domain->updated and races in the
>attach/detach_device code paths.
>
>Changes are boot-tested with lockdep enabled, looked all
>good so far.
>
>Please review.
>
>Thanks,
>
>	Joerg
>
>Joerg Roedel (6):
>  iommu/amd: Remove domain->updated
>  iommu/amd: Remove amd_iommu_devtable_lock
>  iommu/amd: Take domain->lock for complete attach/detach path
>  iommu/amd: Check for busy devices earlier in attach_device()
>  iommu/amd: Lock dev_data in attach/detach code paths
>  iommu/amd: Lock code paths traversing protection_domain->dev_list
>
> drivers/iommu/amd_iommu.c       | 166 ++++++++++++++++----------------
> drivers/iommu/amd_iommu_types.h |   4 +-
> 2 files changed, 85 insertions(+), 85 deletions(-)
>
>-- 
>2.17.1
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Hi Joerg,

What branch is this on top of in your repo?

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 0/6] iommu/amd: Locking Fixes
  2019-09-26  0:25 ` [PATCH 0/6] iommu/amd: Locking Fixes Jerry Snitselaar
@ 2019-09-26  5:46   ` Joerg Roedel
  0 siblings, 0 replies; 22+ messages in thread
From: Joerg Roedel @ 2019-09-26  5:46 UTC (permalink / raw)
  To: Jerry Snitselaar; +Cc: Filippo Sironi, iommu, jroedel

Hi Jerry,

On Wed, Sep 25, 2019 at 05:25:15PM -0700, Jerry Snitselaar wrote:
> On Wed Sep 25 19, Joerg Roedel wrote:
> > Joerg Roedel (6):
> >  iommu/amd: Remove domain->updated
> >  iommu/amd: Remove amd_iommu_devtable_lock
> >  iommu/amd: Take domain->lock for complete attach/detach path
> >  iommu/amd: Check for busy devices earlier in attach_device()
> >  iommu/amd: Lock dev_data in attach/detach code paths
> >  iommu/amd: Lock code paths traversing protection_domain->dev_list
> > 
> > drivers/iommu/amd_iommu.c       | 166 ++++++++++++++++----------------
> > drivers/iommu/amd_iommu_types.h |   4 +-
> > 2 files changed, 85 insertions(+), 85 deletions(-)
> 
> What branch is this on top of in your repo?

This is on-top of my iommu/fixes branch in the iommu-tree.

HTH,

	Joerg
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^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 1/6] iommu/amd: Remove domain->updated
  2019-09-25 13:22 ` [PATCH 1/6] iommu/amd: Remove domain->updated Joerg Roedel
  2019-09-25 15:45   ` Sironi, Filippo via iommu
@ 2019-09-26  6:18   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Jerry Snitselaar @ 2019-09-26  6:18 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi, iommu, jroedel

On Wed Sep 25 19, Joerg Roedel wrote:
>From: Joerg Roedel <jroedel@suse.de>
>
>This struct member was used to track whether a domain
>change requires updates to the device-table and IOMMU cache
>flushes. The problem is, that access to this field is racy
>since locking in the common mapping code-paths has been
>eliminated.
>
>Move the updated field to the stack to get rid of all
>potential races and remove the field from the struct.
>
>Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
>Signed-off-by: Joerg Roedel <jroedel@suse.de>
>---
> drivers/iommu/amd_iommu.c       | 49 +++++++++++++++++----------------
> drivers/iommu/amd_iommu_types.h |  1 -
> 2 files changed, 25 insertions(+), 25 deletions(-)
>
>diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>index 7bdce3b10f3d..042854bbc5bc 100644
>--- a/drivers/iommu/amd_iommu.c
>+++ b/drivers/iommu/amd_iommu.c
>@@ -1458,10 +1458,11 @@ static void free_pagetable(struct protection_domain *domain)
>  * another level increases the size of the address space by 9 bits to a size up
>  * to 64 bits.
>  */
>-static void increase_address_space(struct protection_domain *domain,
>+static bool increase_address_space(struct protection_domain *domain,
> 				   gfp_t gfp)
> {
> 	unsigned long flags;
>+	bool ret = false;
> 	u64 *pte;
>
> 	spin_lock_irqsave(&domain->lock, flags);
>@@ -1478,19 +1479,21 @@ static void increase_address_space(struct protection_domain *domain,
> 					iommu_virt_to_phys(domain->pt_root));
> 	domain->pt_root  = pte;
> 	domain->mode    += 1;
>-	domain->updated  = true;
>+
>+	ret = true;
>
> out:
> 	spin_unlock_irqrestore(&domain->lock, flags);
>
>-	return;
>+	return ret;
> }
>
> static u64 *alloc_pte(struct protection_domain *domain,
> 		      unsigned long address,
> 		      unsigned long page_size,
> 		      u64 **pte_page,
>-		      gfp_t gfp)
>+		      gfp_t gfp,
>+		      bool *updated)
> {
> 	int level, end_lvl;
> 	u64 *pte, *page;
>@@ -1498,7 +1501,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
> 	BUG_ON(!is_power_of_2(page_size));
>
> 	while (address > PM_LEVEL_SIZE(domain->mode))
>-		increase_address_space(domain, gfp);
>+		*updated = increase_address_space(domain, gfp) || *updated;
>
> 	level   = domain->mode - 1;
> 	pte     = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
>@@ -1530,7 +1533,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
> 			for (i = 0; i < count; ++i)
> 				cmpxchg64(&lpte[i], __pte, 0ULL);
>
>-			domain->updated = true;
>+			*updated = true;
> 			continue;
> 		}
>
>@@ -1547,7 +1550,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
> 			if (cmpxchg64(pte, __pte, __npte) != __pte)
> 				free_page((unsigned long)page);
> 			else if (IOMMU_PTE_PRESENT(__pte))
>-				domain->updated = true;
>+				*updated = true;
>
> 			continue;
> 		}
>@@ -1656,28 +1659,29 @@ static int iommu_map_page(struct protection_domain *dom,
> 			  gfp_t gfp)
> {
> 	struct page *freelist = NULL;
>+	bool updated = false;
> 	u64 __pte, *pte;
>-	int i, count;
>+	int ret, i, count;
>
> 	BUG_ON(!IS_ALIGNED(bus_addr, page_size));
> 	BUG_ON(!IS_ALIGNED(phys_addr, page_size));
>
>+	ret = -EINVAL;
> 	if (!(prot & IOMMU_PROT_MASK))
>-		return -EINVAL;
>+		goto out;
>
> 	count = PAGE_SIZE_PTE_COUNT(page_size);
>-	pte   = alloc_pte(dom, bus_addr, page_size, NULL, gfp);
>+	pte   = alloc_pte(dom, bus_addr, page_size, NULL, gfp, &updated);
>
>-	if (!pte) {
>-		update_domain(dom);
>-		return -ENOMEM;
>-	}
>+	ret = -ENOMEM;
>+	if (!pte)
>+		goto out;
>
> 	for (i = 0; i < count; ++i)
> 		freelist = free_clear_pte(&pte[i], pte[i], freelist);
>
> 	if (freelist != NULL)
>-		dom->updated = true;
>+		updated = true;
>
> 	if (count > 1) {
> 		__pte = PAGE_SIZE_PTE(__sme_set(phys_addr), page_size);
>@@ -1693,12 +1697,16 @@ static int iommu_map_page(struct protection_domain *dom,
> 	for (i = 0; i < count; ++i)
> 		pte[i] = __pte;
>
>-	update_domain(dom);
>+	ret = 0;
>+
>+out:
>+	if (updated)
>+		update_domain(dom);
>
> 	/* Everything flushed out, free pages now */
> 	free_page_list(freelist);
>
>-	return 0;
>+	return ret;
> }
>
> static unsigned long iommu_unmap_page(struct protection_domain *dom,
>@@ -2399,15 +2407,10 @@ static void update_device_table(struct protection_domain *domain)
>
> static void update_domain(struct protection_domain *domain)
> {
>-	if (!domain->updated)
>-		return;
>-
> 	update_device_table(domain);
>
> 	domain_flush_devices(domain);
> 	domain_flush_tlb_pde(domain);
>-
>-	domain->updated = false;
> }
>
> static int dir2prot(enum dma_data_direction direction)
>@@ -3333,7 +3336,6 @@ void amd_iommu_domain_direct_map(struct iommu_domain *dom)
>
> 	/* Update data structure */
> 	domain->mode    = PAGE_MODE_NONE;
>-	domain->updated = true;
>
> 	/* Make changes visible to IOMMUs */
> 	update_domain(domain);
>@@ -3379,7 +3381,6 @@ int amd_iommu_domain_enable_v2(struct iommu_domain *dom, int pasids)
>
> 	domain->glx      = levels;
> 	domain->flags   |= PD_IOMMUV2_MASK;
>-	domain->updated  = true;
>
> 	update_domain(domain);
>
>diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
>index 9ac229e92b07..0186501ab971 100644
>--- a/drivers/iommu/amd_iommu_types.h
>+++ b/drivers/iommu/amd_iommu_types.h
>@@ -475,7 +475,6 @@ struct protection_domain {
> 	int glx;		/* Number of levels for GCR3 table */
> 	u64 *gcr3_tbl;		/* Guest CR3 table */
> 	unsigned long flags;	/* flags to find out type of domain */
>-	bool updated;		/* complete domain flush required */
> 	unsigned dev_cnt;	/* devices assigned to this domain */
> 	unsigned dev_iommu[MAX_IOMMUS]; /* per-IOMMU reference count */
> };
>-- 
>2.17.1
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock
  2019-09-25 13:22 ` [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock Joerg Roedel
  2019-09-25 15:50   ` Sironi, Filippo via iommu
@ 2019-09-26  6:24   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Jerry Snitselaar @ 2019-09-26  6:24 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi, iommu, jroedel

On Wed Sep 25 19, Joerg Roedel wrote:
>From: Joerg Roedel <jroedel@suse.de>
>
>The lock is not necessary because the device table does not
>contain shared state that needs protection. Locking is only
>needed on an individual entry basis, and that needs to
>happen on the iommu_dev_data level.
>
>Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
>Signed-off-by: Joerg Roedel <jroedel@suse.de>
>---
> drivers/iommu/amd_iommu.c | 23 ++++++-----------------
> 1 file changed, 6 insertions(+), 17 deletions(-)
>
>diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>index 042854bbc5bc..37a9c04fc728 100644
>--- a/drivers/iommu/amd_iommu.c
>+++ b/drivers/iommu/amd_iommu.c
>@@ -70,7 +70,6 @@
>  */
> #define AMD_IOMMU_PGSIZES	((~0xFFFUL) & ~(2ULL << 38))
>
>-static DEFINE_SPINLOCK(amd_iommu_devtable_lock);
> static DEFINE_SPINLOCK(pd_bitmap_lock);
>
> /* List of all available dev_data structures */
>@@ -2080,10 +2079,11 @@ static void do_detach(struct iommu_dev_data *dev_data)
> static int __attach_device(struct iommu_dev_data *dev_data,
> 			   struct protection_domain *domain)
> {
>+	unsigned long flags;
> 	int ret;
>
> 	/* lock domain */
>-	spin_lock(&domain->lock);
>+	spin_lock_irqsave(&domain->lock, flags);
>
> 	ret = -EBUSY;
> 	if (dev_data->domain != NULL)
>@@ -2097,7 +2097,7 @@ static int __attach_device(struct iommu_dev_data *dev_data,
> out_unlock:
>
> 	/* ready */
>-	spin_unlock(&domain->lock);
>+	spin_unlock_irqrestore(&domain->lock, flags);
>
> 	return ret;
> }
>@@ -2181,7 +2181,6 @@ static int attach_device(struct device *dev,
> {
> 	struct pci_dev *pdev;
> 	struct iommu_dev_data *dev_data;
>-	unsigned long flags;
> 	int ret;
>
> 	dev_data = get_dev_data(dev);
>@@ -2209,9 +2208,7 @@ static int attach_device(struct device *dev,
> 	}
>
> skip_ats_check:
>-	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
> 	ret = __attach_device(dev_data, domain);
>-	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
>
> 	/*
> 	 * We might boot into a crash-kernel here. The crashed kernel
>@@ -2231,14 +2228,15 @@ static int attach_device(struct device *dev,
> static void __detach_device(struct iommu_dev_data *dev_data)
> {
> 	struct protection_domain *domain;
>+	unsigned long flags;
>
> 	domain = dev_data->domain;
>
>-	spin_lock(&domain->lock);
>+	spin_lock_irqsave(&domain->lock, flags);
>
> 	do_detach(dev_data);
>
>-	spin_unlock(&domain->lock);
>+	spin_unlock_irqrestore(&domain->lock, flags);
> }
>
> /*
>@@ -2248,7 +2246,6 @@ static void detach_device(struct device *dev)
> {
> 	struct protection_domain *domain;
> 	struct iommu_dev_data *dev_data;
>-	unsigned long flags;
>
> 	dev_data = get_dev_data(dev);
> 	domain   = dev_data->domain;
>@@ -2262,10 +2259,7 @@ static void detach_device(struct device *dev)
> 	if (WARN_ON(!dev_data->domain))
> 		return;
>
>-	/* lock device table */
>-	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
> 	__detach_device(dev_data);
>-	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
>
> 	if (!dev_is_pci(dev))
> 		return;
>@@ -2910,9 +2904,6 @@ int __init amd_iommu_init_dma_ops(void)
> static void cleanup_domain(struct protection_domain *domain)
> {
> 	struct iommu_dev_data *entry;
>-	unsigned long flags;
>-
>-	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
>
> 	while (!list_empty(&domain->dev_list)) {
> 		entry = list_first_entry(&domain->dev_list,
>@@ -2920,8 +2911,6 @@ static void cleanup_domain(struct protection_domain *domain)
> 		BUG_ON(!entry->domain);
> 		__detach_device(entry);
> 	}
>-
>-	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
> }
>
> static void protection_domain_free(struct protection_domain *domain)
>-- 
>2.17.1
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

_______________________________________________
iommu mailing list
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https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path
  2019-09-25 13:22 ` [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path Joerg Roedel
  2019-09-25 15:53   ` Sironi, Filippo via iommu
@ 2019-09-26  6:34   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Jerry Snitselaar @ 2019-09-26  6:34 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi, iommu, jroedel

On Wed Sep 25 19, Joerg Roedel wrote:
>From: Joerg Roedel <jroedel@suse.de>
>
>The code-paths before __attach_device() and __detach_device() are called
>also access and modify domain state, so take the domain lock there too.
>This allows to get rid of the __detach_device() function.
>
>Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
>Signed-off-by: Joerg Roedel <jroedel@suse.de>
>---
> drivers/iommu/amd_iommu.c | 65 ++++++++++++++++-----------------------
> 1 file changed, 26 insertions(+), 39 deletions(-)
>
>diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>index 37a9c04fc728..2919168577ff 100644
>--- a/drivers/iommu/amd_iommu.c
>+++ b/drivers/iommu/amd_iommu.c
>@@ -2079,27 +2079,13 @@ static void do_detach(struct iommu_dev_data *dev_data)
> static int __attach_device(struct iommu_dev_data *dev_data,
> 			   struct protection_domain *domain)
> {
>-	unsigned long flags;
>-	int ret;
>-
>-	/* lock domain */
>-	spin_lock_irqsave(&domain->lock, flags);
>-
>-	ret = -EBUSY;
> 	if (dev_data->domain != NULL)
>-		goto out_unlock;
>+		return -EBUSY;
>
> 	/* Attach alias group root */
> 	do_attach(dev_data, domain);
>
>-	ret = 0;
>-
>-out_unlock:
>-
>-	/* ready */
>-	spin_unlock_irqrestore(&domain->lock, flags);
>-
>-	return ret;
>+	return 0;
> }
>
>
>@@ -2181,8 +2167,11 @@ static int attach_device(struct device *dev,
> {
> 	struct pci_dev *pdev;
> 	struct iommu_dev_data *dev_data;
>+	unsigned long flags;
> 	int ret;
>
>+	spin_lock_irqsave(&domain->lock, flags);
>+
> 	dev_data = get_dev_data(dev);
>
> 	if (!dev_is_pci(dev))
>@@ -2190,12 +2179,13 @@ static int attach_device(struct device *dev,
>
> 	pdev = to_pci_dev(dev);
> 	if (domain->flags & PD_IOMMUV2_MASK) {
>+		ret = -EINVAL;
> 		if (!dev_data->passthrough)
>-			return -EINVAL;
>+			goto out;
>
> 		if (dev_data->iommu_v2) {
> 			if (pdev_iommuv2_enable(pdev) != 0)
>-				return -EINVAL;
>+				goto out;
>
> 			dev_data->ats.enabled = true;
> 			dev_data->ats.qdep    = pci_ats_queue_depth(pdev);
>@@ -2219,24 +2209,10 @@ static int attach_device(struct device *dev,
>
> 	domain_flush_complete(domain);
>
>-	return ret;
>-}
>-
>-/*
>- * Removes a device from a protection domain (unlocked)
>- */
>-static void __detach_device(struct iommu_dev_data *dev_data)
>-{
>-	struct protection_domain *domain;
>-	unsigned long flags;
>-
>-	domain = dev_data->domain;
>-
>-	spin_lock_irqsave(&domain->lock, flags);
>-
>-	do_detach(dev_data);
>-
>+out:
> 	spin_unlock_irqrestore(&domain->lock, flags);
>+
>+	return ret;
> }
>
> /*
>@@ -2246,10 +2222,13 @@ static void detach_device(struct device *dev)
> {
> 	struct protection_domain *domain;
> 	struct iommu_dev_data *dev_data;
>+	unsigned long flags;
>
> 	dev_data = get_dev_data(dev);
> 	domain   = dev_data->domain;
>
>+	spin_lock_irqsave(&domain->lock, flags);
>+
> 	/*
> 	 * First check if the device is still attached. It might already
> 	 * be detached from its domain because the generic
>@@ -2257,12 +2236,12 @@ static void detach_device(struct device *dev)
> 	 * our alias handling.
> 	 */
> 	if (WARN_ON(!dev_data->domain))
>-		return;
>+		goto out;
>
>-	__detach_device(dev_data);
>+	do_detach(dev_data);
>
> 	if (!dev_is_pci(dev))
>-		return;
>+		goto out;
>
> 	if (domain->flags & PD_IOMMUV2_MASK && dev_data->iommu_v2)
> 		pdev_iommuv2_disable(to_pci_dev(dev));
>@@ -2270,6 +2249,9 @@ static void detach_device(struct device *dev)
> 		pci_disable_ats(to_pci_dev(dev));
>
> 	dev_data->ats.enabled = false;
>+
>+out:
>+	spin_unlock_irqrestore(&domain->lock, flags);
> }
>
> static int amd_iommu_add_device(struct device *dev)
>@@ -2904,13 +2886,18 @@ int __init amd_iommu_init_dma_ops(void)
> static void cleanup_domain(struct protection_domain *domain)
> {
> 	struct iommu_dev_data *entry;
>+	unsigned long flags;
>+
>+	spin_lock_irqsave(&domain->lock, flags);
>
> 	while (!list_empty(&domain->dev_list)) {
> 		entry = list_first_entry(&domain->dev_list,
> 					 struct iommu_dev_data, list);
> 		BUG_ON(!entry->domain);
>-		__detach_device(entry);
>+		do_detach(entry);
> 	}
>+
>+	spin_unlock_irqrestore(&domain->lock, flags);
> }
>
> static void protection_domain_free(struct protection_domain *domain)
>-- 
>2.17.1
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device()
  2019-09-25 13:22 ` [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device() Joerg Roedel
  2019-09-25 15:55   ` Sironi, Filippo via iommu
@ 2019-09-26  6:37   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Jerry Snitselaar @ 2019-09-26  6:37 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi, iommu, jroedel

On Wed Sep 25 19, Joerg Roedel wrote:
>From: Joerg Roedel <jroedel@suse.de>
>
>Check early in attach_device whether the device is already attached to a
>domain. This also simplifies the code path so that __attach_device() can
>be removed.
>
>Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
>Signed-off-by: Joerg Roedel <jroedel@suse.de>
>---
> drivers/iommu/amd_iommu.c | 25 +++++++------------------
> 1 file changed, 7 insertions(+), 18 deletions(-)
>
>diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>index 2919168577ff..459247c32dc0 100644
>--- a/drivers/iommu/amd_iommu.c
>+++ b/drivers/iommu/amd_iommu.c
>@@ -2072,23 +2072,6 @@ static void do_detach(struct iommu_dev_data *dev_data)
> 	domain->dev_cnt                 -= 1;
> }
>
>-/*
>- * If a device is not yet associated with a domain, this function makes the
>- * device visible in the domain
>- */
>-static int __attach_device(struct iommu_dev_data *dev_data,
>-			   struct protection_domain *domain)
>-{
>-	if (dev_data->domain != NULL)
>-		return -EBUSY;
>-
>-	/* Attach alias group root */
>-	do_attach(dev_data, domain);
>-
>-	return 0;
>-}
>-
>-
> static void pdev_iommuv2_disable(struct pci_dev *pdev)
> {
> 	pci_disable_ats(pdev);
>@@ -2174,6 +2157,10 @@ static int attach_device(struct device *dev,
>
> 	dev_data = get_dev_data(dev);
>
>+	ret = -EBUSY;
>+	if (dev_data->domain != NULL)
>+		goto out;
>+
> 	if (!dev_is_pci(dev))
> 		goto skip_ats_check;
>
>@@ -2198,7 +2185,9 @@ static int attach_device(struct device *dev,
> 	}
>
> skip_ats_check:
>-	ret = __attach_device(dev_data, domain);
>+	ret = 0;
>+
>+	do_attach(dev_data, domain);
>
> 	/*
> 	 * We might boot into a crash-kernel here. The crashed kernel
>-- 
>2.17.1
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths
  2019-09-25 13:22 ` [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths Joerg Roedel
  2019-09-25 15:56   ` Sironi, Filippo via iommu
@ 2019-09-26  6:41   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Jerry Snitselaar @ 2019-09-26  6:41 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi, iommu, jroedel

On Wed Sep 25 19, Joerg Roedel wrote:
>From: Joerg Roedel <jroedel@suse.de>
>
>Make sure that attaching a detaching a device can't race against each
>other and protect the iommu_dev_data with a spin_lock in these code
>paths.
>
>Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
>Signed-off-by: Joerg Roedel <jroedel@suse.de>
>---
> drivers/iommu/amd_iommu.c       | 9 +++++++++
> drivers/iommu/amd_iommu_types.h | 3 +++
> 2 files changed, 12 insertions(+)
>
>diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>index 459247c32dc0..bac4e20a5919 100644
>--- a/drivers/iommu/amd_iommu.c
>+++ b/drivers/iommu/amd_iommu.c
>@@ -201,6 +201,7 @@ static struct iommu_dev_data *alloc_dev_data(u16 devid)
> 	if (!dev_data)
> 		return NULL;
>
>+	spin_lock_init(&dev_data->lock);
> 	dev_data->devid = devid;
> 	ratelimit_default_init(&dev_data->rs);
>
>@@ -2157,6 +2158,8 @@ static int attach_device(struct device *dev,
>
> 	dev_data = get_dev_data(dev);
>
>+	spin_lock(&dev_data->lock);
>+
> 	ret = -EBUSY;
> 	if (dev_data->domain != NULL)
> 		goto out;
>@@ -2199,6 +2202,8 @@ static int attach_device(struct device *dev,
> 	domain_flush_complete(domain);
>
> out:
>+	spin_unlock(&dev_data->lock);
>+
> 	spin_unlock_irqrestore(&domain->lock, flags);
>
> 	return ret;
>@@ -2218,6 +2223,8 @@ static void detach_device(struct device *dev)
>
> 	spin_lock_irqsave(&domain->lock, flags);
>
>+	spin_lock(&dev_data->lock);
>+
> 	/*
> 	 * First check if the device is still attached. It might already
> 	 * be detached from its domain because the generic
>@@ -2240,6 +2247,8 @@ static void detach_device(struct device *dev)
> 	dev_data->ats.enabled = false;
>
> out:
>+	spin_unlock(&dev_data->lock);
>+
> 	spin_unlock_irqrestore(&domain->lock, flags);
> }
>
>diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
>index 0186501ab971..c9c1612d52e0 100644
>--- a/drivers/iommu/amd_iommu_types.h
>+++ b/drivers/iommu/amd_iommu_types.h
>@@ -633,6 +633,9 @@ struct devid_map {
>  * This struct contains device specific data for the IOMMU
>  */
> struct iommu_dev_data {
>+	/*Protect against attach/detach races */
>+	spinlock_t lock;
>+
> 	struct list_head list;		  /* For domain->dev_list */
> 	struct llist_node dev_data_list;  /* For global dev_data_list */
> 	struct protection_domain *domain; /* Domain the device is bound to */
>-- 
>2.17.1
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list
  2019-09-25 13:23 ` [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list Joerg Roedel
  2019-09-25 15:58   ` Sironi, Filippo via iommu
@ 2019-09-26  6:48   ` Jerry Snitselaar
  1 sibling, 0 replies; 22+ messages in thread
From: Jerry Snitselaar @ 2019-09-26  6:48 UTC (permalink / raw)
  To: Joerg Roedel; +Cc: Filippo Sironi, iommu, jroedel

On Wed Sep 25 19, Joerg Roedel wrote:
>From: Joerg Roedel <jroedel@suse.de>
>
>The traversing of this list requires protection_domain->lock to be taken
>to avoid nasty races with attach/detach code. Make sure the lock is held
>on all code-paths traversing this list.
>
>Reported-by: Filippo Sironi <sironi@amazon.de>
>Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
>Signed-off-by: Joerg Roedel <jroedel@suse.de>
>---
> drivers/iommu/amd_iommu.c | 25 ++++++++++++++++++++++++-
> 1 file changed, 24 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>index bac4e20a5919..9c26976a0f99 100644
>--- a/drivers/iommu/amd_iommu.c
>+++ b/drivers/iommu/amd_iommu.c
>@@ -1334,8 +1334,12 @@ static void domain_flush_np_cache(struct protection_domain *domain,
> 		dma_addr_t iova, size_t size)
> {
> 	if (unlikely(amd_iommu_np_cache)) {
>+		unsigned long flags;
>+
>+		spin_lock_irqsave(&domain->lock, flags);
> 		domain_flush_pages(domain, iova, size);
> 		domain_flush_complete(domain);
>+		spin_unlock_irqrestore(&domain->lock, flags);
> 	}
> }
>
>@@ -1700,8 +1704,13 @@ static int iommu_map_page(struct protection_domain *dom,
> 	ret = 0;
>
> out:
>-	if (updated)
>+	if (updated) {
>+		unsigned long flags;
>+
>+		spin_lock_irqsave(&dom->lock, flags);
> 		update_domain(dom);
>+		spin_unlock_irqrestore(&dom->lock, flags);
>+	}
>
> 	/* Everything flushed out, free pages now */
> 	free_page_list(freelist);
>@@ -1857,8 +1866,12 @@ static void free_gcr3_table(struct protection_domain *domain)
>
> static void dma_ops_domain_flush_tlb(struct dma_ops_domain *dom)
> {
>+	unsigned long flags;
>+
>+	spin_lock_irqsave(&dom->domain.lock, flags);
> 	domain_flush_tlb(&dom->domain);
> 	domain_flush_complete(&dom->domain);
>+	spin_unlock_irqrestore(&dom->domain.lock, flags);
> }
>
> static void iova_domain_flush_tlb(struct iova_domain *iovad)
>@@ -2414,6 +2427,7 @@ static dma_addr_t __map_single(struct device *dev,
> {
> 	dma_addr_t offset = paddr & ~PAGE_MASK;
> 	dma_addr_t address, start, ret;
>+	unsigned long flags;
> 	unsigned int pages;
> 	int prot = 0;
> 	int i;
>@@ -2451,8 +2465,10 @@ static dma_addr_t __map_single(struct device *dev,
> 		iommu_unmap_page(&dma_dom->domain, start, PAGE_SIZE);
> 	}
>
>+	spin_lock_irqsave(&dma_dom->domain.lock, flags);
> 	domain_flush_tlb(&dma_dom->domain);
> 	domain_flush_complete(&dma_dom->domain);
>+	spin_unlock_irqrestore(&dma_dom->domain.lock, flags);
>
> 	dma_ops_free_iova(dma_dom, address, pages);
>
>@@ -2481,8 +2497,12 @@ static void __unmap_single(struct dma_ops_domain *dma_dom,
> 	}
>
> 	if (amd_iommu_unmap_flush) {
>+		unsigned long flags;
>+
>+		spin_lock_irqsave(&dma_dom->domain.lock, flags);
> 		domain_flush_tlb(&dma_dom->domain);
> 		domain_flush_complete(&dma_dom->domain);
>+		spin_unlock_irqrestore(&dma_dom->domain.lock, flags);
> 		dma_ops_free_iova(dma_dom, dma_addr, pages);
> 	} else {
> 		pages = __roundup_pow_of_two(pages);
>@@ -3246,9 +3266,12 @@ static bool amd_iommu_is_attach_deferred(struct iommu_domain *domain,
> static void amd_iommu_flush_iotlb_all(struct iommu_domain *domain)
> {
> 	struct protection_domain *dom = to_pdomain(domain);
>+	unsigned long flags;
>
>+	spin_lock_irqsave(&dom->lock, flags);
> 	domain_flush_tlb_pde(dom);
> 	domain_flush_complete(dom);
>+	spin_unlock_irqrestore(&dom->lock, flags);
> }
>
> static void amd_iommu_iotlb_sync(struct iommu_domain *domain,
>-- 
>2.17.1
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 22+ messages in thread

end of thread, back to index

Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
2019-09-25 13:22 ` [PATCH 1/6] iommu/amd: Remove domain->updated Joerg Roedel
2019-09-25 15:45   ` Sironi, Filippo via iommu
2019-09-26  6:18   ` Jerry Snitselaar
2019-09-25 13:22 ` [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock Joerg Roedel
2019-09-25 15:50   ` Sironi, Filippo via iommu
2019-09-25 15:52     ` Sironi, Filippo via iommu
2019-09-26  6:24   ` Jerry Snitselaar
2019-09-25 13:22 ` [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path Joerg Roedel
2019-09-25 15:53   ` Sironi, Filippo via iommu
2019-09-26  6:34   ` Jerry Snitselaar
2019-09-25 13:22 ` [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device() Joerg Roedel
2019-09-25 15:55   ` Sironi, Filippo via iommu
2019-09-26  6:37   ` Jerry Snitselaar
2019-09-25 13:22 ` [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths Joerg Roedel
2019-09-25 15:56   ` Sironi, Filippo via iommu
2019-09-26  6:41   ` Jerry Snitselaar
2019-09-25 13:23 ` [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list Joerg Roedel
2019-09-25 15:58   ` Sironi, Filippo via iommu
2019-09-26  6:48   ` Jerry Snitselaar
2019-09-26  0:25 ` [PATCH 0/6] iommu/amd: Locking Fixes Jerry Snitselaar
2019-09-26  5:46   ` Joerg Roedel

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