2021-04-15 00:51:33

by Jacob Pan

[permalink] [raw]
Subject: [PATCH v2 1/2] iommu/sva: Tighten SVA bind API with explicit flags

The void* drvdata parameter isn't really used in iommu_sva_bind_device()
API, the current IDXD code "borrows" the drvdata for a VT-d private flag
for supervisor SVA usage.

Supervisor/Privileged mode request is a generic feature. It should be
promoted from the VT-d vendor driver to the generic code.

This patch replaces void* drvdata with a unsigned int flags parameter
and adjusts callers accordingly.

Link: https://lore.kernel.org/linux-iommu/YFhiMLR35WWMW%2FHu@myrica/
Suggested-by: Jean-Philippe Brucker <[email protected]>
Signed-off-by: Jacob Pan <[email protected]>
---
drivers/dma/idxd/cdev.c | 2 +-
drivers/dma/idxd/init.c | 7 +++----
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 5 ++++-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 4 ++--
drivers/iommu/intel/svm.c | 14 ++++----------
drivers/iommu/iommu.c | 9 ++++++---
drivers/misc/uacce/uacce.c | 2 +-
include/linux/intel-iommu.h | 2 +-
include/linux/intel-svm.h | 17 ++---------------
include/linux/iommu.h | 19 ++++++++++++++++---
10 files changed, 40 insertions(+), 41 deletions(-)

diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index 0db9b82ed8cf..21ec82bc47b6 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -103,7 +103,7 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp)
filp->private_data = ctx;

if (device_pasid_enabled(idxd)) {
- sva = iommu_sva_bind_device(dev, current->mm, NULL);
+ sva = iommu_sva_bind_device(dev, current->mm, 0);
if (IS_ERR(sva)) {
rc = PTR_ERR(sva);
dev_err(dev, "pasid allocation failed: %d\n", rc);
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 085a0c3b62c6..82a0985ad6dc 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -14,7 +14,6 @@
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/device.h>
#include <linux/idr.h>
-#include <linux/intel-svm.h>
#include <linux/iommu.h>
#include <uapi/linux/idxd.h>
#include <linux/dmaengine.h>
@@ -300,13 +299,13 @@ static struct idxd_device *idxd_alloc(struct pci_dev *pdev)

static int idxd_enable_system_pasid(struct idxd_device *idxd)
{
- int flags;
+ unsigned int flags;
unsigned int pasid;
struct iommu_sva *sva;

- flags = SVM_FLAG_SUPERVISOR_MODE;
+ flags = IOMMU_SVA_BIND_SUPERVISOR;

- sva = iommu_sva_bind_device(&idxd->pdev->dev, NULL, &flags);
+ sva = iommu_sva_bind_device(&idxd->pdev->dev, NULL, flags);
if (IS_ERR(sva)) {
dev_warn(&idxd->pdev->dev,
"iommu sva bind failed: %ld\n", PTR_ERR(sva));
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index bb251cab61f3..145ceb2fc5da 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -354,12 +354,15 @@ __arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
}

struct iommu_sva *
-arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, unsigned int flags)
{
struct iommu_sva *handle;
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

+ if (flags)
+ return ERR_PTR(-EINVAL);
+
if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
return ERR_PTR(-EINVAL);

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index f985817c967a..b971d4dcf090 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -711,7 +711,7 @@ bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master);
int arm_smmu_master_enable_sva(struct arm_smmu_master *master);
int arm_smmu_master_disable_sva(struct arm_smmu_master *master);
struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm,
- void *drvdata);
+ unsigned int flags);
void arm_smmu_sva_unbind(struct iommu_sva *handle);
u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle);
void arm_smmu_sva_notifier_synchronize(void);
@@ -742,7 +742,7 @@ static inline int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
}

static inline struct iommu_sva *
-arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, unsigned int flags)
{
return ERR_PTR(-ENODEV);
}
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 574a7e657a9a..d4840821f7b5 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -486,12 +486,9 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
} else
pasid_max = 1 << 20;

- /* Bind supervisor PASID shuld have mm = NULL */
- if (flags & SVM_FLAG_SUPERVISOR_MODE) {
- if (!ecap_srs(iommu->ecap) || mm) {
- pr_err("Supervisor PASID with user provided mm.\n");
- return -EINVAL;
- }
+ if ((flags & IOMMU_SVA_BIND_SUPERVISOR) && !ecap_srs(iommu->ecap)) {
+ pr_err("Supervisor PASID not supported.\n");
+ return -EINVAL;
}

if (!(flags & SVM_FLAG_PRIVATE_PASID)) {
@@ -1059,11 +1056,10 @@ static irqreturn_t prq_event_thread(int irq, void *d)

#define to_intel_svm_dev(handle) container_of(handle, struct intel_svm_dev, sva)
struct iommu_sva *
-intel_svm_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+intel_svm_bind(struct device *dev, struct mm_struct *mm, unsigned int flags)
{
struct iommu_sva *sva = ERR_PTR(-EINVAL);
struct intel_svm_dev *sdev = NULL;
- unsigned int flags = 0;
int ret;

/*
@@ -1071,8 +1067,6 @@ intel_svm_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
* It will require shared SVM data structures, i.e. combine io_mm
* and intel_svm etc.
*/
- if (drvdata)
- flags = *(unsigned int *)drvdata;
mutex_lock(&pasid_mutex);
ret = intel_svm_bind_mm(dev, flags, NULL, mm, &sdev);
if (ret)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index d0b0a15dba84..eefa541d8674 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2962,6 +2962,7 @@ EXPORT_SYMBOL_GPL(iommu_aux_get_pasid);
* iommu_sva_bind_device() - Bind a process address space to a device
* @dev: the device
* @mm: the mm to bind, caller must hold a reference to it
+ * @flags: options for the bind operation defined as IOMMU_SVA_BIND_*
*
* Create a bond between device and address space, allowing the device to access
* the mm using the returned PASID. If a bond already exists between @device and
@@ -2974,7 +2975,7 @@ EXPORT_SYMBOL_GPL(iommu_aux_get_pasid);
* On error, returns an ERR_PTR value.
*/
struct iommu_sva *
-iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
+iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, unsigned int flags)
{
struct iommu_group *group;
struct iommu_sva *handle = ERR_PTR(-EINVAL);
@@ -2987,6 +2988,9 @@ iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
if (!group)
return ERR_PTR(-ENODEV);

+ /* Supervisor SVA does not need the current mm */
+ if ((flags & IOMMU_SVA_BIND_SUPERVISOR) && mm)
+ return ERR_PTR(-EINVAL);
/* Ensure device count and domain don't change while we're binding */
mutex_lock(&group->mutex);

@@ -2999,8 +3003,7 @@ iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
if (iommu_group_device_count(group) != 1)
goto out_unlock;

- handle = ops->sva_bind(dev, mm, drvdata);
-
+ handle = ops->sva_bind(dev, mm, flags);
out_unlock:
mutex_unlock(&group->mutex);
iommu_group_put(group);
diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index d07af4edfcac..27e0e04dfcab 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -99,7 +99,7 @@ static int uacce_bind_queue(struct uacce_device *uacce, struct uacce_queue *q)
if (!(uacce->flags & UACCE_DEV_SVA))
return 0;

- handle = iommu_sva_bind_device(uacce->parent, current->mm, NULL);
+ handle = iommu_sva_bind_device(uacce->parent, current->mm, 0);
if (IS_ERR(handle))
return PTR_ERR(handle);

diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 1bc46b88711a..cdff752aacdd 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -757,7 +757,7 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
struct iommu_gpasid_bind_data *data);
int intel_svm_unbind_gpasid(struct device *dev, u32 pasid);
struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct *mm,
- void *drvdata);
+ unsigned int flags);
void intel_svm_unbind(struct iommu_sva *handle);
u32 intel_svm_get_pasid(struct iommu_sva *handle);
int intel_svm_page_response(struct device *dev, struct iommu_fault_event *evt,
diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h
index 39d368a810b8..ef6b75326a2b 100644
--- a/include/linux/intel-svm.h
+++ b/include/linux/intel-svm.h
@@ -30,30 +30,17 @@ struct svm_dev_ops {
* if there is no other way to do so. It should be used sparingly, if at all.
*/
#define SVM_FLAG_PRIVATE_PASID (1<<0)
-
-/*
- * The SVM_FLAG_SUPERVISOR_MODE flag requests a PASID which can be used only
- * for access to kernel addresses. No IOTLB flushes are automatically done
- * for kernel mappings; it is valid only for access to the kernel's static
- * 1:1 mapping of physical memory — not to vmalloc or even module mappings.
- * A future API addition may permit the use of such ranges, by means of an
- * explicit IOTLB flush call (akin to the DMA API's unmap method).
- *
- * It is unlikely that we will ever hook into flush_tlb_kernel_range() to
- * do such IOTLB flushes automatically.
- */
-#define SVM_FLAG_SUPERVISOR_MODE (1<<1)
/*
* The SVM_FLAG_GUEST_MODE flag is used when a PASID bind is for guest
* processes. Compared to the host bind, the primary differences are:
* 1. mm life cycle management
* 2. fault reporting
*/
-#define SVM_FLAG_GUEST_MODE (1<<2)
+#define SVM_FLAG_GUEST_MODE (1<<1)
/*
* The SVM_FLAG_GUEST_PASID flag is used when a guest has its own PASID space,
* which requires guest and host PASID translation at both directions.
*/
-#define SVM_FLAG_GUEST_PASID (1<<3)
+#define SVM_FLAG_GUEST_PASID (1<<2)

#endif /* __INTEL_SVM_H__ */
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5e7fe519430a..ba81cec0b086 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -164,6 +164,19 @@ enum iommu_dev_features {

#define IOMMU_PASID_INVALID (-1U)

+/*
+ * The IOMMU_SVA_BIND_SUPERVISOR flag requests a PASID which can be used only
+ * for access to kernel addresses. No IOTLB flushes are automatically done
+ * for kernel mappings; it is valid only for access to the kernel's static
+ * 1:1 mapping of physical memory — not to vmalloc or even module mappings.
+ * A future API addition may permit the use of such ranges, by means of an
+ * explicit IOTLB flush call (akin to the DMA API's unmap method).
+ *
+ * It is unlikely that we will ever hook into flush_tlb_kernel_range() to
+ * do such IOTLB flushes automatically.
+ */
+#define IOMMU_SVA_BIND_SUPERVISOR BIT(0)
+
#ifdef CONFIG_IOMMU_API

/**
@@ -287,7 +300,7 @@ struct iommu_ops {
int (*aux_get_pasid)(struct iommu_domain *domain, struct device *dev);

struct iommu_sva *(*sva_bind)(struct device *dev, struct mm_struct *mm,
- void *drvdata);
+ unsigned int flags);
void (*sva_unbind)(struct iommu_sva *handle);
u32 (*sva_get_pasid)(struct iommu_sva *handle);

@@ -640,7 +653,7 @@ int iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev);

struct iommu_sva *iommu_sva_bind_device(struct device *dev,
struct mm_struct *mm,
- void *drvdata);
+ unsigned int flags);
void iommu_sva_unbind_device(struct iommu_sva *handle);
u32 iommu_sva_get_pasid(struct iommu_sva *handle);

@@ -1015,7 +1028,7 @@ iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev)
}

static inline struct iommu_sva *
-iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
+iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, unsigned int flags)
{
return NULL;
}
--
2.25.1


2021-04-15 06:41:25

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] iommu/sva: Tighten SVA bind API with explicit flags

On Wed, Apr 14, 2021 at 08:27:56AM -0700, Jacob Pan wrote:
> static int idxd_enable_system_pasid(struct idxd_device *idxd)
> {
> - int flags;
> + unsigned int flags;
> unsigned int pasid;
> struct iommu_sva *sva;
>
> - flags = SVM_FLAG_SUPERVISOR_MODE;
> + flags = IOMMU_SVA_BIND_SUPERVISOR;
>
> - sva = iommu_sva_bind_device(&idxd->pdev->dev, NULL, &flags);
> + sva = iommu_sva_bind_device(&idxd->pdev->dev, NULL, flags);

Please also remove the now pointless flags variable.

> +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, unsigned int flags)

Pleae avoid the pointless overly long line.

> -#define SVM_FLAG_GUEST_PASID (1<<3)
> +#define SVM_FLAG_GUEST_PASID (1<<2)

This flag is entirely unused, please just remove it in a prep patch
rather than renumbering it.

> static inline struct iommu_sva *
> -iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
> +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, unsigned int flags)

Same overy long line here.

2021-04-15 18:52:06

by Jacob Pan

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] iommu/sva: Tighten SVA bind API with explicit flags

Hi Christoph,

Thanks for the review.

On Thu, 15 Apr 2021 07:40:33 +0100, Christoph Hellwig <[email protected]>
wrote:

> On Wed, Apr 14, 2021 at 08:27:56AM -0700, Jacob Pan wrote:
> > static int idxd_enable_system_pasid(struct idxd_device *idxd)
> > {
> > - int flags;
> > + unsigned int flags;
> > unsigned int pasid;
> > struct iommu_sva *sva;
> >
> > - flags = SVM_FLAG_SUPERVISOR_MODE;
> > + flags = IOMMU_SVA_BIND_SUPERVISOR;
> >
> > - sva = iommu_sva_bind_device(&idxd->pdev->dev, NULL, &flags);
> > + sva = iommu_sva_bind_device(&idxd->pdev->dev, NULL, flags);
>
> Please also remove the now pointless flags variable.
>
Good catch.

> > +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm,
> > unsigned int flags)
>
> Pleae avoid the pointless overly long line.
>
> > -#define SVM_FLAG_GUEST_PASID (1<<3)
> > +#define SVM_FLAG_GUEST_PASID (1<<2)
>
> This flag is entirely unused, please just remove it in a prep patch
> rather than renumbering it.
>
You are right. The flag was set and intended to be used by the guest IO
page request patches by Baolu.

As you might be aware, we are restructuring the guest SVA uAPI according to
Jason's proposal, can we wait until we have a clear solution? We may
refactor lots of code.

> > static inline struct iommu_sva *
> > -iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void
> > *drvdata) +iommu_sva_bind_device(struct device *dev, struct mm_struct
> > *mm, unsigned int flags)
>
> Same overy long line here.
This is temporary as the mm parameter will be removed in the next patch.

Thanks,

Jacob