* [PATCH 1/5] iommu/intel: Add __init for dmar_register_bus_notifier()
2018-01-24 13:19 [PATCH 0/5] iommu/intel: Handle DMAR faults in a wq Dmitry Safonov
@ 2018-01-24 13:19 ` Dmitry Safonov
2018-01-24 13:19 ` [PATCH 2/5] iommu/intel: Clean/document fault status flags Dmitry Safonov
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2018-01-24 13:19 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, Dmitry Safonov, Alex Williamson, David Woodhouse,
Ingo Molnar, Joerg Roedel, Lu Baolu, iommu
It's called only from intel_iommu_init(), which is init function.
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
drivers/iommu/dmar.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 9a7ffd13c7f0..accf58388bdb 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -806,7 +806,7 @@ int __init dmar_dev_scope_init(void)
return dmar_dev_scope_status;
}
-void dmar_register_bus_notifier(void)
+void __init dmar_register_bus_notifier(void)
{
bus_register_notifier(&pci_bus_type, &dmar_pci_bus_nb);
}
--
2.13.6
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/5] iommu/intel: Clean/document fault status flags
2018-01-24 13:19 [PATCH 0/5] iommu/intel: Handle DMAR faults in a wq Dmitry Safonov
2018-01-24 13:19 ` [PATCH 1/5] iommu/intel: Add __init for dmar_register_bus_notifier() Dmitry Safonov
@ 2018-01-24 13:19 ` Dmitry Safonov
2018-01-24 13:19 ` [PATCH 3/5] iommu/intel: Introduce clear_primary_faults() helper Dmitry Safonov
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2018-01-24 13:19 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, Dmitry Safonov, Alex Williamson, David Woodhouse,
Ingo Molnar, Joerg Roedel, Lu Baolu, iommu
So one could decode them without opening the specification.
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
include/linux/intel-iommu.h | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index f3274d9f46a2..a4dc9c2875cc 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -207,12 +207,12 @@
#define DMA_FECTL_IM (((u32)1) << 31)
/* FSTS_REG */
-#define DMA_FSTS_PPF ((u32)2)
-#define DMA_FSTS_PFO ((u32)1)
-#define DMA_FSTS_IQE (1 << 4)
-#define DMA_FSTS_ICE (1 << 5)
-#define DMA_FSTS_ITE (1 << 6)
-#define DMA_FSTS_PRO (1 << 7)
+#define DMA_FSTS_PFO (1 << 0) /* Primary Fault Overflow */
+#define DMA_FSTS_PPF (1 << 1) /* Primary Pending Fault */
+#define DMA_FSTS_IQE (1 << 4) /* Invalidation Queue Error */
+#define DMA_FSTS_ICE (1 << 5) /* Invalidation Completion Error */
+#define DMA_FSTS_ITE (1 << 6) /* Invalidation Time-out Error */
+#define DMA_FSTS_PRO (1 << 7) /* Page Request Overflow */
#define dma_fsts_fault_record_index(s) (((s) >> 8) & 0xff)
/* FRCD_REG, 32 bits access */
--
2.13.6
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/5] iommu/intel: Introduce clear_primary_faults() helper
2018-01-24 13:19 [PATCH 0/5] iommu/intel: Handle DMAR faults in a wq Dmitry Safonov
2018-01-24 13:19 ` [PATCH 1/5] iommu/intel: Add __init for dmar_register_bus_notifier() Dmitry Safonov
2018-01-24 13:19 ` [PATCH 2/5] iommu/intel: Clean/document fault status flags Dmitry Safonov
@ 2018-01-24 13:19 ` Dmitry Safonov
2018-01-24 13:19 ` [PATCH 4/5] iommu/intel: Handle DMAR faults on workqueue Dmitry Safonov
2018-01-24 13:19 ` [PATCH 5/5] iommu/intel: Rename dmar_fault() => dmar_serve_faults() Dmitry Safonov
4 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2018-01-24 13:19 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, Dmitry Safonov, Alex Williamson, David Woodhouse,
Ingo Molnar, Joerg Roedel, Lu Baolu, iommu
To my mind it's a bit more readable - and I will re-use it in the next
patch.
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
drivers/iommu/dmar.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index accf58388bdb..33fb4244e438 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1611,6 +1611,15 @@ static int dmar_fault_do_one(struct intel_iommu *iommu, int type,
return 0;
}
+static void clear_primary_faults(struct intel_iommu *iommu)
+{
+ volatile void __iomem *fsts = iommu->reg + DMAR_FSTS_REG;
+
+ assert_raw_spin_locked(&iommu->register_lock);
+
+ writel(DMA_FSTS_PFO | DMA_FSTS_PPF | DMA_FSTS_PRO, fsts);
+}
+
#define PRIMARY_FAULT_REG_LEN (16)
irqreturn_t dmar_fault(int irq, void *dev_id)
{
@@ -1679,8 +1688,7 @@ irqreturn_t dmar_fault(int irq, void *dev_id)
raw_spin_lock_irqsave(&iommu->register_lock, flag);
}
- writel(DMA_FSTS_PFO | DMA_FSTS_PPF | DMA_FSTS_PRO,
- iommu->reg + DMAR_FSTS_REG);
+ clear_primary_faults(iommu);
unlock_exit:
raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
--
2.13.6
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 4/5] iommu/intel: Handle DMAR faults on workqueue
2018-01-24 13:19 [PATCH 0/5] iommu/intel: Handle DMAR faults in a wq Dmitry Safonov
` (2 preceding siblings ...)
2018-01-24 13:19 ` [PATCH 3/5] iommu/intel: Introduce clear_primary_faults() helper Dmitry Safonov
@ 2018-01-24 13:19 ` Dmitry Safonov
2018-01-24 13:19 ` [PATCH 5/5] iommu/intel: Rename dmar_fault() => dmar_serve_faults() Dmitry Safonov
4 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2018-01-24 13:19 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, Dmitry Safonov, Alex Williamson, David Woodhouse,
Ingo Molnar, Joerg Roedel, Lu Baolu, iommu
dmar_fault() reports/handles/cleans DMAR faults in a cycle one-by-one.
The nuisance is that it's set as a irq handler and runs with disabled
interrupts - which works OK if you have only a couple of DMAR faults,
but becomes a problem if your intel iommu has a plenty of mappings.
We have a test that checks flapping of PCI link. Once or twice it had
stuck on soft lockup (which is panic for the typical switch):
dmar: DMAR:[DMA Write] Request device [4a:00.0] fault addr 5e1a3000
DMAR:[fault reason 02] Present bit in context entry is clear
NMI watchdog: BUG: soft lockup - CPU#8 stuck for 21s!
CPU: 8 PID: 2774 Comm: SuperServer
Call Trace:
generic_exec_single+0x11b/0x12d
? flush_tlb_func+0x0/0x18a
smp_call_function_single+0x89/0xb5
smp_call_function_many+0xef/0x207
native_flush_tlb_others+0x2e/0x30
flush_tlb_mm_range+0x139/0x18a
tlb_flush_mmu_tlbonly+0x35/0x85
tlb_flush_mmu+0x13/0x1f
tlb_finish_mmu+0x14/0x39
unmap_region+0xda/0xec
do_munmap+0x273/0x2f5
vm_munmap+0x45/0x5e
SyS_munmap+0x26/0x2f
sysenter_dispatch+0x7/0x25
Kernel panic - not syncing: softlockup: hung tasks
sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0
Call Trace:
<IRQ>
wait_for_xmitr+0x26/0x8f
serial8250_console_putchar+0x1c/0x2c
uart_console_write+0x40/0x4b
serial8250_console_write+0xe6/0x13f
call_console_drivers.constprop.13+0xce/0x103
console_unlock+0x1f8/0x39b
? local_clock+0x21/0x23
vprintk_emit+0x39e/0x3e6
printk+0x4d/0x4f
dmar_fault+0x1ab/0x1fd
handle_irq_event_percpu+0x8a/0x1f5
handle_irq_event+0x41/0x61
handle_edge_irq+0xe1/0xfa
handle_irq+0x155/0x166
do_IRQ+0x5a/0xea
ret_from_intr+0x0/0x15
<EOI>
arch_cpu_idle+0xf/0x11
cpu_startup_entry+0x22f/0x3cb
rest_init+0x80/0x84
start_kernel+0x470/0x47d
x86_64_start_reservations+0x2a/0x2c
x86_64_start_kernel+0x14b/0x15a
Move DMAR faults clearing out of irq-disabled critical section by
proceeding with that in a workqueue thread.
The next patch will correct the definition of dmar_fault().
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
drivers/iommu/dmar.c | 48 ++++++++++++++++++++++++++++++++++++++++++++-
drivers/iommu/intel-iommu.c | 6 ++++++
include/linux/dmar.h | 1 +
3 files changed, 54 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 33fb4244e438..34a53aeede38 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -71,6 +71,12 @@ struct acpi_table_header * __initdata dmar_tbl;
static int dmar_dev_scope_status = 1;
static unsigned long dmar_seq_ids[BITS_TO_LONGS(DMAR_UNITS_SUPPORTED)];
+static struct workqueue_struct *fault_wq;
+struct fault {
+ struct work_struct work;
+ struct intel_iommu *iommu;
+};
+
static int alloc_iommu(struct dmar_drhd_unit *drhd);
static void free_iommu(struct intel_iommu *iommu);
@@ -811,6 +817,14 @@ void __init dmar_register_bus_notifier(void)
bus_register_notifier(&pci_bus_type, &dmar_pci_bus_nb);
}
+int __init dmar_init_workqueue(void)
+{
+ fault_wq = alloc_workqueue("dmar_fault", WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
+ if (fault_wq == NULL)
+ return -ENOMEM;
+
+ return 0;
+}
int __init dmar_table_init(void)
{
@@ -1695,6 +1709,38 @@ irqreturn_t dmar_fault(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static void dmar_fault_work(struct work_struct *work)
+{
+ struct fault *fault = container_of(work, struct fault, work);
+
+ dmar_fault(-1, (void*)fault->iommu);
+}
+
+static irqreturn_t dmar_fault_handler(int irq, void *dev_id)
+{
+ struct intel_iommu *iommu = dev_id;
+ struct fault *fault;
+
+ fault = kzalloc(sizeof(*fault), GFP_ATOMIC);
+ if (fault == NULL) {
+ unsigned long flag;
+
+ /* During OOM - clear faults and let device re-fault */
+ raw_spin_lock_irqsave(&iommu->register_lock, flag);
+ clear_primary_faults(iommu);
+ raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
+
+ return IRQ_HANDLED;
+ }
+
+ fault->iommu = iommu;
+ INIT_WORK(&fault->work, dmar_fault_work);
+
+ queue_work(fault_wq, &fault->work);
+
+ return IRQ_HANDLED;
+}
+
int dmar_set_interrupt(struct intel_iommu *iommu)
{
int irq, ret;
@@ -1713,7 +1759,7 @@ int dmar_set_interrupt(struct intel_iommu *iommu)
return -EINVAL;
}
- ret = request_irq(irq, dmar_fault, IRQF_NO_THREAD, iommu->name, iommu);
+ ret = request_irq(irq, dmar_fault_handler, IRQF_NO_THREAD, iommu->name, iommu);
if (ret)
pr_err("Can't request irq\n");
return ret;
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 4a2de34895ec..4869c02652cc 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4784,6 +4784,12 @@ int __init intel_iommu_init(void)
goto out_free_dmar;
}
+ if (dmar_init_workqueue()) {
+ if (force_on)
+ panic("tboot: Failed to init workqueue for DMARs\n");
+ goto out_free_dmar;
+ }
+
if (list_empty(&dmar_rmrr_units))
pr_info("No RMRR found\n");
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index e2433bc50210..5de4932a6ad8 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -113,6 +113,7 @@ static inline bool dmar_rcu_check(void)
extern int dmar_table_init(void);
extern int dmar_dev_scope_init(void);
extern void dmar_register_bus_notifier(void);
+extern int dmar_init_workqueue(void);
extern int dmar_parse_dev_scope(void *start, void *end, int *cnt,
struct dmar_dev_scope **devices, u16 segment);
extern void *dmar_alloc_dev_scope(void *start, void *end, int *cnt);
--
2.13.6
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 5/5] iommu/intel: Rename dmar_fault() => dmar_serve_faults()
2018-01-24 13:19 [PATCH 0/5] iommu/intel: Handle DMAR faults in a wq Dmitry Safonov
` (3 preceding siblings ...)
2018-01-24 13:19 ` [PATCH 4/5] iommu/intel: Handle DMAR faults on workqueue Dmitry Safonov
@ 2018-01-24 13:19 ` Dmitry Safonov
4 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2018-01-24 13:19 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, Dmitry Safonov, Alex Williamson, David Woodhouse,
Ingo Molnar, Joerg Roedel, Lu Baolu, iommu
Fix the return value, parameters and a bit better naming.
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
drivers/iommu/dmar.c | 8 +++-----
drivers/iommu/intel-iommu.c | 2 +-
drivers/iommu/intel_irq_remapping.c | 2 +-
include/linux/dmar.h | 2 +-
4 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 34a53aeede38..37a1147a7592 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1635,9 +1635,8 @@ static void clear_primary_faults(struct intel_iommu *iommu)
}
#define PRIMARY_FAULT_REG_LEN (16)
-irqreturn_t dmar_fault(int irq, void *dev_id)
+void dmar_serve_faults(struct intel_iommu *iommu)
{
- struct intel_iommu *iommu = dev_id;
int reg, fault_index;
u32 fault_status;
unsigned long flag;
@@ -1706,14 +1705,13 @@ irqreturn_t dmar_fault(int irq, void *dev_id)
unlock_exit:
raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
- return IRQ_HANDLED;
}
static void dmar_fault_work(struct work_struct *work)
{
struct fault *fault = container_of(work, struct fault, work);
- dmar_fault(-1, (void*)fault->iommu);
+ dmar_serve_faults(fault->iommu);
}
static irqreturn_t dmar_fault_handler(int irq, void *dev_id)
@@ -1786,7 +1784,7 @@ int __init enable_drhd_fault_handling(void)
/*
* Clear any previous faults.
*/
- dmar_fault(iommu->irq, iommu);
+ dmar_serve_faults(iommu);
fault_status = readl(iommu->reg + DMAR_FSTS_REG);
writel(fault_status, iommu->reg + DMAR_FSTS_REG);
}
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 4869c02652cc..ee98cbce54bd 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3016,7 +3016,7 @@ static void intel_iommu_init_qi(struct intel_iommu *iommu)
/*
* Clear any previous faults.
*/
- dmar_fault(-1, iommu);
+ dmar_serve_faults(iommu);
/*
* Disable queued invalidation if supported and already enabled
* before OS handover.
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 66f69af2c219..0958fdc76564 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -558,7 +558,7 @@ static int intel_setup_irq_remapping(struct intel_iommu *iommu)
/*
* Clear previous faults.
*/
- dmar_fault(-1, iommu);
+ dmar_serve_faults(iommu);
dmar_disable_qi(iommu);
if (dmar_enable_qi(iommu)) {
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 5de4932a6ad8..6e9a5e4ac73a 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -280,7 +280,7 @@ extern void dmar_msi_mask(struct irq_data *data);
extern void dmar_msi_read(int irq, struct msi_msg *msg);
extern void dmar_msi_write(int irq, struct msi_msg *msg);
extern int dmar_set_interrupt(struct intel_iommu *iommu);
-extern irqreturn_t dmar_fault(int irq, void *dev_id);
+extern void dmar_serve_faults(struct intel_iommu *iommu);
extern int dmar_alloc_hwirq(int id, int node, void *arg);
extern void dmar_free_hwirq(int irq);
--
2.13.6
^ permalink raw reply related [flat|nested] 6+ messages in thread