Re: [PATCH v2] ocxl: Allow contexts to be attached with a NULL mm
On 20/6/19 2:12 pm, Alastair D'Silva wrote:
From: Alastair D'Silva
If an OpenCAPI context is to be used directly by a kernel driver, there
may not be a suitable mm to use.
The patch makes the mm parameter to ocxl_context_attach optional.
Signed-off-by: Alastair D'Silva
Acked-by: Andrew Donnellan
---
arch/powerpc/mm/book3s64/radix_tlb.c | 5 +
drivers/misc/ocxl/context.c | 9 ++---
drivers/misc/ocxl/link.c | 28
3 files changed, 35 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c
b/arch/powerpc/mm/book3s64/radix_tlb.c
index bb9835681315..ce8a77fae6a7 100644
--- a/arch/powerpc/mm/book3s64/radix_tlb.c
+++ b/arch/powerpc/mm/book3s64/radix_tlb.c
@@ -666,6 +666,11 @@ EXPORT_SYMBOL(radix__flush_tlb_page);
#define radix__flush_all_mm radix__local_flush_all_mm
#endif /* CONFIG_SMP */
+/*
+ * If kernel TLBIs ever become local rather than global, then
+ * drivers/misc/ocxl/link.c:ocxl_link_add_pe will need some work, as it
+ * assumes kernel TLBIs are global.
+ */
void radix__flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
_tlbie_pid(0, RIC_FLUSH_ALL);
diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index bab9c9364184..994563a078eb 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -69,6 +69,7 @@ static void xsl_fault_error(void *data, u64 addr, u64 dsisr)
int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct
*mm)
{
int rc;
+ unsigned long pidr = 0;
// Locks both status & tidr
mutex_lock(>status_mutex);
@@ -77,9 +78,11 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr,
struct mm_struct *mm)
goto out;
}
- rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
- mm->context.id, ctx->tidr, amr, mm,
- xsl_fault_error, ctx);
+ if (mm)
+ pidr = mm->context.id;
+
+ rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, pidr, ctx->tidr,
+ amr, mm, xsl_fault_error, ctx);
if (rc)
goto out;
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index cce5b0d64505..58d111afd9f6 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -224,6 +224,17 @@ static irqreturn_t xsl_fault_handler(int irq, void *data)
ack_irq(spa, ADDRESS_ERROR);
return IRQ_HANDLED;
}
+
+ if (!pe_data->mm) {
+ /*
+* translation fault from a kernel context - an OpenCAPI
+* device tried to access a bad kernel address
+*/
+ rcu_read_unlock();
+ pr_warn("Unresolved OpenCAPI xsl fault in kernel context\n");
+ ack_irq(spa, ADDRESS_ERROR);
+ return IRQ_HANDLED;
+ }
WARN_ON(pe_data->mm->context.id != pid);
if (mmget_not_zero(pe_data->mm)) {
@@ -523,7 +534,13 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32
pidr, u32 tidr,
pe->amr = cpu_to_be64(amr);
pe->software_state = cpu_to_be32(SPA_PE_VALID);
- mm_context_add_copro(mm);
+ /*
+* For user contexts, register a copro so that TLBIs are seen
+* by the nest MMU. If we have a kernel context, TLBIs are
+* already global.
+*/
+ if (mm)
+ mm_context_add_copro(mm);
/*
* Barrier is to make sure PE is visible in the SPA before it
* is used by the device. It also helps with the global TLBI
@@ -546,7 +563,8 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32
pidr, u32 tidr,
* have a reference on mm_users. Incrementing mm_count solves
* the problem.
*/
- mmgrab(mm);
+ if (mm)
+ mmgrab(mm);
trace_ocxl_context_add(current->pid, spa->spa_mem, pasid, pidr, tidr);
unlock:
mutex_unlock(>spa_lock);
@@ -652,8 +670,10 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
if (!pe_data) {
WARN(1, "Couldn't find pe data when removing PE\n");
} else {
- mm_context_remove_copro(pe_data->mm);
- mmdrop(pe_data->mm);
+ if (pe_data->mm) {
+ mm_context_remove_copro(pe_data->mm);
+ mmdrop(pe_data->mm);
+ }
kfree_rcu(pe_data, rcu);
}
unlock:
--
Andrew Donnellan OzLabs, ADL Canberra
a...@linux.ibm.com IBM Australia Limited
Re: [PATCH v2] ocxl: Allow contexts to be attached with a NULL mm
Le 20/06/2019 à 06:12, Alastair D'Silva a écrit :
From: Alastair D'Silva
If an OpenCAPI context is to be used directly by a kernel driver, there
may not be a suitable mm to use.
The patch makes the mm parameter to ocxl_context_attach optional.
Signed-off-by: Alastair D'Silva
---
Thanks for the update.
Acked-by: Frederic Barrat
arch/powerpc/mm/book3s64/radix_tlb.c | 5 +
drivers/misc/ocxl/context.c | 9 ++---
drivers/misc/ocxl/link.c | 28
3 files changed, 35 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c
b/arch/powerpc/mm/book3s64/radix_tlb.c
index bb9835681315..ce8a77fae6a7 100644
--- a/arch/powerpc/mm/book3s64/radix_tlb.c
+++ b/arch/powerpc/mm/book3s64/radix_tlb.c
@@ -666,6 +666,11 @@ EXPORT_SYMBOL(radix__flush_tlb_page);
#define radix__flush_all_mm radix__local_flush_all_mm
#endif /* CONFIG_SMP */
+/*
+ * If kernel TLBIs ever become local rather than global, then
+ * drivers/misc/ocxl/link.c:ocxl_link_add_pe will need some work, as it
+ * assumes kernel TLBIs are global.
+ */
void radix__flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
_tlbie_pid(0, RIC_FLUSH_ALL);
diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index bab9c9364184..994563a078eb 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -69,6 +69,7 @@ static void xsl_fault_error(void *data, u64 addr, u64 dsisr)
int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct
*mm)
{
int rc;
+ unsigned long pidr = 0;
// Locks both status & tidr
mutex_lock(>status_mutex);
@@ -77,9 +78,11 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr,
struct mm_struct *mm)
goto out;
}
- rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
- mm->context.id, ctx->tidr, amr, mm,
- xsl_fault_error, ctx);
+ if (mm)
+ pidr = mm->context.id;
+
+ rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, pidr, ctx->tidr,
+ amr, mm, xsl_fault_error, ctx);
if (rc)
goto out;
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index cce5b0d64505..58d111afd9f6 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -224,6 +224,17 @@ static irqreturn_t xsl_fault_handler(int irq, void *data)
ack_irq(spa, ADDRESS_ERROR);
return IRQ_HANDLED;
}
+
+ if (!pe_data->mm) {
+ /*
+* translation fault from a kernel context - an OpenCAPI
+* device tried to access a bad kernel address
+*/
+ rcu_read_unlock();
+ pr_warn("Unresolved OpenCAPI xsl fault in kernel context\n");
+ ack_irq(spa, ADDRESS_ERROR);
+ return IRQ_HANDLED;
+ }
WARN_ON(pe_data->mm->context.id != pid);
if (mmget_not_zero(pe_data->mm)) {
@@ -523,7 +534,13 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32
pidr, u32 tidr,
pe->amr = cpu_to_be64(amr);
pe->software_state = cpu_to_be32(SPA_PE_VALID);
- mm_context_add_copro(mm);
+ /*
+* For user contexts, register a copro so that TLBIs are seen
+* by the nest MMU. If we have a kernel context, TLBIs are
+* already global.
+*/
+ if (mm)
+ mm_context_add_copro(mm);
/*
* Barrier is to make sure PE is visible in the SPA before it
* is used by the device. It also helps with the global TLBI
@@ -546,7 +563,8 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32
pidr, u32 tidr,
* have a reference on mm_users. Incrementing mm_count solves
* the problem.
*/
- mmgrab(mm);
+ if (mm)
+ mmgrab(mm);
trace_ocxl_context_add(current->pid, spa->spa_mem, pasid, pidr, tidr);
unlock:
mutex_unlock(>spa_lock);
@@ -652,8 +670,10 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
if (!pe_data) {
WARN(1, "Couldn't find pe data when removing PE\n");
} else {
- mm_context_remove_copro(pe_data->mm);
- mmdrop(pe_data->mm);
+ if (pe_data->mm) {
+ mm_context_remove_copro(pe_data->mm);
+ mmdrop(pe_data->mm);
+ }
kfree_rcu(pe_data, rcu);
}
unlock:
Re: [PATCH v2] ocxl: Allow contexts to be attached with a NULL mm
Alastair D'Silva's on June 20, 2019 2:12 pm: > From: Alastair D'Silva > > If an OpenCAPI context is to be used directly by a kernel driver, there > may not be a suitable mm to use. > > The patch makes the mm parameter to ocxl_context_attach optional. > > Signed-off-by: Alastair D'Silva Yeah I don't think you need to manage a kernel context explicitly because it will always be flushed with tlbie, comment helps. For the powerpc/mm bit, Acked-by: Nicholas Piggin
[PATCH v2] ocxl: Allow contexts to be attached with a NULL mm
From: Alastair D'Silva
If an OpenCAPI context is to be used directly by a kernel driver, there
may not be a suitable mm to use.
The patch makes the mm parameter to ocxl_context_attach optional.
Signed-off-by: Alastair D'Silva
---
arch/powerpc/mm/book3s64/radix_tlb.c | 5 +
drivers/misc/ocxl/context.c | 9 ++---
drivers/misc/ocxl/link.c | 28
3 files changed, 35 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c
b/arch/powerpc/mm/book3s64/radix_tlb.c
index bb9835681315..ce8a77fae6a7 100644
--- a/arch/powerpc/mm/book3s64/radix_tlb.c
+++ b/arch/powerpc/mm/book3s64/radix_tlb.c
@@ -666,6 +666,11 @@ EXPORT_SYMBOL(radix__flush_tlb_page);
#define radix__flush_all_mm radix__local_flush_all_mm
#endif /* CONFIG_SMP */
+/*
+ * If kernel TLBIs ever become local rather than global, then
+ * drivers/misc/ocxl/link.c:ocxl_link_add_pe will need some work, as it
+ * assumes kernel TLBIs are global.
+ */
void radix__flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
_tlbie_pid(0, RIC_FLUSH_ALL);
diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index bab9c9364184..994563a078eb 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -69,6 +69,7 @@ static void xsl_fault_error(void *data, u64 addr, u64 dsisr)
int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct
*mm)
{
int rc;
+ unsigned long pidr = 0;
// Locks both status & tidr
mutex_lock(>status_mutex);
@@ -77,9 +78,11 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr,
struct mm_struct *mm)
goto out;
}
- rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
- mm->context.id, ctx->tidr, amr, mm,
- xsl_fault_error, ctx);
+ if (mm)
+ pidr = mm->context.id;
+
+ rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, pidr, ctx->tidr,
+ amr, mm, xsl_fault_error, ctx);
if (rc)
goto out;
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index cce5b0d64505..58d111afd9f6 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -224,6 +224,17 @@ static irqreturn_t xsl_fault_handler(int irq, void *data)
ack_irq(spa, ADDRESS_ERROR);
return IRQ_HANDLED;
}
+
+ if (!pe_data->mm) {
+ /*
+* translation fault from a kernel context - an OpenCAPI
+* device tried to access a bad kernel address
+*/
+ rcu_read_unlock();
+ pr_warn("Unresolved OpenCAPI xsl fault in kernel context\n");
+ ack_irq(spa, ADDRESS_ERROR);
+ return IRQ_HANDLED;
+ }
WARN_ON(pe_data->mm->context.id != pid);
if (mmget_not_zero(pe_data->mm)) {
@@ -523,7 +534,13 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32
pidr, u32 tidr,
pe->amr = cpu_to_be64(amr);
pe->software_state = cpu_to_be32(SPA_PE_VALID);
- mm_context_add_copro(mm);
+ /*
+* For user contexts, register a copro so that TLBIs are seen
+* by the nest MMU. If we have a kernel context, TLBIs are
+* already global.
+*/
+ if (mm)
+ mm_context_add_copro(mm);
/*
* Barrier is to make sure PE is visible in the SPA before it
* is used by the device. It also helps with the global TLBI
@@ -546,7 +563,8 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32
pidr, u32 tidr,
* have a reference on mm_users. Incrementing mm_count solves
* the problem.
*/
- mmgrab(mm);
+ if (mm)
+ mmgrab(mm);
trace_ocxl_context_add(current->pid, spa->spa_mem, pasid, pidr, tidr);
unlock:
mutex_unlock(>spa_lock);
@@ -652,8 +670,10 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
if (!pe_data) {
WARN(1, "Couldn't find pe data when removing PE\n");
} else {
- mm_context_remove_copro(pe_data->mm);
- mmdrop(pe_data->mm);
+ if (pe_data->mm) {
+ mm_context_remove_copro(pe_data->mm);
+ mmdrop(pe_data->mm);
+ }
kfree_rcu(pe_data, rcu);
}
unlock:
--
2.21.0
