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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v12 1/6] IOMMU: add a timeout parameter for device IOTLB invalidation
From: Quan Xu <quan.xu@xxxxxxxxx>
The parameter 'iommu_dev_iotlb_timeout' specifies the timeout
of device IOTLB invalidation in milliseconds. By default, the
timeout is 1000 milliseconds, which can be boot-time changed.
We also confirmed with VT-d hardware team that 1 milliseconds
is large enough for VT-d IOMMU internal invalidation.
the existing panic() is eliminated and we bubble up the timeout
of device IOTLB invalidation for further processing, as the
PCI-e Address Translation Services (ATS) mandates a timeout of
60 seconds for device IOTLB invalidation. Obviously we can't
spin for 60 seconds or otherwise Xen hypervisor hangs.
Add a __must_check annotation. The followup patch titled
'VT-d IOTLB/Context/IEC flush issue' addresses the __mustcheck.
That is the other callers of this routine (two or three levels up)
ignore the return code. This patch does not address this but the
other does.
Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
CC: Feng Wu <feng.wu@xxxxxxxxx>
CC: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
---
v12:
1. enhance commit message.
2. change timeout from 1ms to 1000ms.
3. change IOMMU_QI_TIMEOUT to VTD_QI_TIMEOUT, with VTD_QI_TIMEOUT
having its MILLISECS() dropped.
4. enhance the whole expression of 'timeout = ...'
5. drop a blank line that doesn't belong here.
---
docs/misc/xen-command-line.markdown | 9 +++++++++
xen/drivers/passthrough/iommu.c | 3 +++
xen/drivers/passthrough/vtd/qinval.c | 32 +++++++++++++++++++++-----------
xen/include/xen/iommu.h | 2 ++
4 files changed, 35 insertions(+), 11 deletions(-)
diff --git a/docs/misc/xen-command-line.markdown
b/docs/misc/xen-command-line.markdown
index 7a271c0..0046f0d 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -1015,6 +1015,15 @@ debug hypervisor only).
>> Enable IOMMU debugging code (implies `verbose`).
+### iommu\_dev\_iotlb\_timeout
+> `= <integer>`
+
+> Default: `1000`
+
+Specify the timeout of the device IOTLB invalidation in milliseconds.
+By default, the timeout is 1000 ms. When you see error 'Queue invalidate
+wait descriptor timed out', try increasing this value.
+
### iommu\_inclusive\_mapping (VT-d)
> `= <boolean>`
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index ef80b3c..7656aeb 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -24,6 +24,9 @@
static void parse_iommu_param(char *s);
static void iommu_dump_p2m_table(unsigned char key);
+unsigned int __read_mostly iommu_dev_iotlb_timeout = 1000;
+integer_param("iommu_dev_iotlb_timeout", iommu_dev_iotlb_timeout);
+
/*
* The 'iommu' parameter enables the IOMMU. Optional comma separated
* value may contain:
diff --git a/xen/drivers/passthrough/vtd/qinval.c
b/xen/drivers/passthrough/vtd/qinval.c
index aa7841a..4788d5f 100644
--- a/xen/drivers/passthrough/vtd/qinval.c
+++ b/xen/drivers/passthrough/vtd/qinval.c
@@ -28,6 +28,8 @@
#include "vtd.h"
#include "extern.h"
+#define VTD_QI_TIMEOUT 1
+
static void print_qi_regs(struct iommu *iommu)
{
u64 val;
@@ -130,10 +132,10 @@ static void queue_invalidate_iotlb(struct iommu *iommu,
spin_unlock_irqrestore(&iommu->register_lock, flags);
}
-static int queue_invalidate_wait(struct iommu *iommu,
- u8 iflag, u8 sw, u8 fn)
+static int __must_check queue_invalidate_wait(struct iommu *iommu,
+ u8 iflag, u8 sw, u8 fn,
+ bool_t flush_dev_iotlb)
{
- s_time_t start_time;
volatile u32 poll_slot = QINVAL_STAT_INIT;
unsigned int index;
unsigned long flags;
@@ -163,14 +165,20 @@ static int queue_invalidate_wait(struct iommu *iommu,
/* Now we don't support interrupt method */
if ( sw )
{
+ s_time_t timeout;
+
/* In case all wait descriptor writes to same addr with same data */
- start_time = NOW();
+ timeout = NOW() + MILLISECS(flush_dev_iotlb ?
+ iommu_dev_iotlb_timeout : VTD_QI_TIMEOUT);
+
while ( poll_slot != QINVAL_STAT_DONE )
{
- if ( NOW() > (start_time + DMAR_OPERATION_TIMEOUT) )
+ if ( NOW() > timeout )
{
print_qi_regs(iommu);
- panic("queue invalidate wait descriptor was not executed");
+ printk(XENLOG_WARNING VTDPREFIX
+ " Queue invalidate wait descriptor timed out\n");
+ return -ETIMEDOUT;
}
cpu_relax();
}
@@ -180,12 +188,14 @@ static int queue_invalidate_wait(struct iommu *iommu,
return -EOPNOTSUPP;
}
-static int invalidate_sync(struct iommu *iommu)
+static int __must_check invalidate_sync(struct iommu *iommu,
+ bool_t flush_dev_iotlb)
{
struct qi_ctrl *qi_ctrl = iommu_qi_ctrl(iommu);
if ( qi_ctrl->qinval_maddr )
- return queue_invalidate_wait(iommu, 0, 1, 1);
+ return queue_invalidate_wait(iommu, 0, 1, 1, flush_dev_iotlb);
+
return 0;
}
@@ -254,7 +264,7 @@ static int __iommu_flush_iec(struct iommu *iommu, u8 granu,
u8 im, u16 iidx)
int ret;
queue_invalidate_iec(iommu, granu, im, iidx);
- ret = invalidate_sync(iommu);
+ ret = invalidate_sync(iommu, 0);
/*
* reading vt-d architecture register will ensure
* draining happens in implementation independent way.
@@ -300,7 +310,7 @@ static int __must_check flush_context_qi(void *_iommu, u16
did,
{
queue_invalidate_context(iommu, did, sid, fm,
type >> DMA_CCMD_INVL_GRANU_OFFSET);
- ret = invalidate_sync(iommu);
+ ret = invalidate_sync(iommu, 0);
}
return ret;
}
@@ -344,7 +354,7 @@ static int __must_check flush_iotlb_qi(void *_iommu, u16
did, u64 addr,
dw, did, size_order, 0, addr);
if ( flush_dev_iotlb )
ret = dev_invalidate_iotlb(iommu, did, addr, size_order, type);
- rc = invalidate_sync(iommu);
+ rc = invalidate_sync(iommu, flush_dev_iotlb);
if ( !ret )
ret = rc;
}
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 8b23cc9..a759f2b 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -35,6 +35,8 @@ extern bool_t iommu_hap_pt_share;
extern bool_t iommu_debug;
extern bool_t amd_iommu_perdev_intremap;
+extern unsigned int iommu_dev_iotlb_timeout;
+
#define IOMMU_PAGE_SIZE(sz) (1UL << PAGE_SHIFT_##sz)
#define IOMMU_PAGE_MASK(sz) (~(u64)0 << PAGE_SHIFT_##sz)
#define IOMMU_PAGE_ALIGN(sz, addr) (((addr) + ~PAGE_MASK_##sz) &
PAGE_MASK_##sz)
--
1.9.1
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