* [PATCH RESEND 2/5] Drivers: hv: vmbus: handle various crash scenarios
2016-05-01 2:21 ` [PATCH RESEND 1/5] Drivers: hv: kvp: fix IP Failover K. Y. Srinivasan
@ 2016-05-01 2:21 ` K. Y. Srinivasan
2016-05-01 2:21 ` [PATCH RESEND 3/5] Drivers: hv: balloon: don't crash when memory is added in non-sorted order K. Y. Srinivasan
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: K. Y. Srinivasan @ 2016-05-01 2:21 UTC (permalink / raw)
To: gregkh, linux-kernel, devel, olaf, apw, vkuznets, jasowang
Cc: K. Y. Srinivasan
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Kdump keeps biting. Turns out CHANNELMSG_UNLOAD_RESPONSE is always
delivered to the CPU which was used for initial contact or to CPU0
depending on host version. vmbus_wait_for_unload() doesn't account for
the fact that in case we're crashing on some other CPU we won't get the
CHANNELMSG_UNLOAD_RESPONSE message and our wait on the current CPU will
never end.
Do the following:
1) Check for completion_done() in the loop. In case interrupt handler is
still alive we'll get the confirmation we need.
2) Read message pages for all CPUs message page as we're unsure where
CHANNELMSG_UNLOAD_RESPONSE is going to be delivered to. We can race with
still-alive interrupt handler doing the same, add cmpxchg() to
vmbus_signal_eom() to not lose CHANNELMSG_UNLOAD_RESPONSE message.
3) Cleanup message pages on all CPUs. This is required (at least for the
current CPU as we're clearing CPU0 messages now but we may want to bring
up additional CPUs on crash) as new messages won't be delivered till we
consume what's pending. On boot we'll place message pages somewhere else
and we won't be able to read stale messages.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
drivers/hv/channel_mgmt.c | 58 +++++++++++++++++++++++++++++++++-----------
drivers/hv/hyperv_vmbus.h | 16 +++++++++++-
drivers/hv/vmbus_drv.c | 7 +++--
3 files changed, 61 insertions(+), 20 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 38b682ba..b6c1211 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -597,27 +597,55 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
static void vmbus_wait_for_unload(void)
{
- int cpu = smp_processor_id();
- void *page_addr = hv_context.synic_message_page[cpu];
- struct hv_message *msg = (struct hv_message *)page_addr +
- VMBUS_MESSAGE_SINT;
+ int cpu;
+ void *page_addr;
+ struct hv_message *msg;
struct vmbus_channel_message_header *hdr;
- bool unloaded = false;
+ u32 message_type;
+ /*
+ * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
+ * used for initial contact or to CPU0 depending on host version. When
+ * we're crashing on a different CPU let's hope that IRQ handler on
+ * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
+ * functional and vmbus_unload_response() will complete
+ * vmbus_connection.unload_event. If not, the last thing we can do is
+ * read message pages for all CPUs directly.
+ */
while (1) {
- if (READ_ONCE(msg->header.message_type) == HVMSG_NONE) {
- mdelay(10);
- continue;
- }
+ if (completion_done(&vmbus_connection.unload_event))
+ break;
- hdr = (struct vmbus_channel_message_header *)msg->u.payload;
- if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
- unloaded = true;
+ for_each_online_cpu(cpu) {
+ page_addr = hv_context.synic_message_page[cpu];
+ msg = (struct hv_message *)page_addr +
+ VMBUS_MESSAGE_SINT;
- vmbus_signal_eom(msg);
+ message_type = READ_ONCE(msg->header.message_type);
+ if (message_type == HVMSG_NONE)
+ continue;
- if (unloaded)
- break;
+ hdr = (struct vmbus_channel_message_header *)
+ msg->u.payload;
+
+ if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
+ complete(&vmbus_connection.unload_event);
+
+ vmbus_signal_eom(msg, message_type);
+ }
+
+ mdelay(10);
+ }
+
+ /*
+ * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
+ * maybe-pending messages on all CPUs to be able to receive new
+ * messages after we reconnect.
+ */
+ for_each_online_cpu(cpu) {
+ page_addr = hv_context.synic_message_page[cpu];
+ msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
+ msg->header.message_type = HVMSG_NONE;
}
}
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index e5203e4..718b5c7 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -625,9 +625,21 @@ extern struct vmbus_channel_message_table_entry
channel_message_table[CHANNELMSG_COUNT];
/* Free the message slot and signal end-of-message if required */
-static inline void vmbus_signal_eom(struct hv_message *msg)
+static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
{
- msg->header.message_type = HVMSG_NONE;
+ /*
+ * On crash we're reading some other CPU's message page and we need
+ * to be careful: this other CPU may already had cleared the header
+ * and the host may already had delivered some other message there.
+ * In case we blindly write msg->header.message_type we're going
+ * to lose it. We can still lose a message of the same type but
+ * we count on the fact that there can only be one
+ * CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
+ * on crash.
+ */
+ if (cmpxchg(&msg->header.message_type, old_msg_type,
+ HVMSG_NONE) != old_msg_type)
+ return;
/*
* Make sure the write to MessageType (ie set to
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index a29a6c0..952f20f 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -712,7 +712,7 @@ static void hv_process_timer_expiration(struct hv_message *msg, int cpu)
if (dev->event_handler)
dev->event_handler(dev);
- vmbus_signal_eom(msg);
+ vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
}
void vmbus_on_msg_dpc(unsigned long data)
@@ -724,8 +724,9 @@ void vmbus_on_msg_dpc(unsigned long data)
struct vmbus_channel_message_header *hdr;
struct vmbus_channel_message_table_entry *entry;
struct onmessage_work_context *ctx;
+ u32 message_type = msg->header.message_type;
- if (msg->header.message_type == HVMSG_NONE)
+ if (message_type == HVMSG_NONE)
/* no msg */
return;
@@ -750,7 +751,7 @@ void vmbus_on_msg_dpc(unsigned long data)
entry->message_handler(hdr);
msg_handled:
- vmbus_signal_eom(msg);
+ vmbus_signal_eom(msg, message_type);
}
static void vmbus_isr(void)
--
1.7.4.1
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH RESEND 3/5] Drivers: hv: balloon: don't crash when memory is added in non-sorted order
2016-05-01 2:21 ` [PATCH RESEND 1/5] Drivers: hv: kvp: fix IP Failover K. Y. Srinivasan
2016-05-01 2:21 ` [PATCH RESEND 2/5] Drivers: hv: vmbus: handle various crash scenarios K. Y. Srinivasan
@ 2016-05-01 2:21 ` K. Y. Srinivasan
2016-05-01 2:21 ` [PATCH RESEND 4/5] Drivers: hv: balloon: reset host_specified_ha_region K. Y. Srinivasan
2016-05-01 2:21 ` [PATCH RESEND 5/5] tools: hv: lsvmbus: add pci pass-through UUID K. Y. Srinivasan
3 siblings, 0 replies; 6+ messages in thread
From: K. Y. Srinivasan @ 2016-05-01 2:21 UTC (permalink / raw)
To: gregkh, linux-kernel, devel, olaf, apw, vkuznets, jasowang
Cc: K. Y. Srinivasan
From: Vitaly Kuznetsov <vkuznets@redhat.com>
When we iterate through all HA regions in handle_pg_range() we have an
assumption that all these regions are sorted in the list and the
'start_pfn >= has->end_pfn' check is enough to find the proper region.
Unfortunately it's not the case with WS2016 where host can hot-add regions
in a different order. We end up modifying the wrong HA region and crashing
later on pages online. Modify the check to make sure we found the region
we were searching for while iterating. Fix the same check in pfn_covered()
as well.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
drivers/hv/hv_balloon.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index b853b4b..43af913 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -714,7 +714,7 @@ static bool pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
* If the pfn range we are dealing with is not in the current
* "hot add block", move on.
*/
- if ((start_pfn >= has->end_pfn))
+ if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
continue;
/*
* If the current hot add-request extends beyond
@@ -768,7 +768,7 @@ static unsigned long handle_pg_range(unsigned long pg_start,
* If the pfn range we are dealing with is not in the current
* "hot add block", move on.
*/
- if ((start_pfn >= has->end_pfn))
+ if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
continue;
old_covered_state = has->covered_end_pfn;
--
1.7.4.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH RESEND 4/5] Drivers: hv: balloon: reset host_specified_ha_region
2016-05-01 2:21 ` [PATCH RESEND 1/5] Drivers: hv: kvp: fix IP Failover K. Y. Srinivasan
2016-05-01 2:21 ` [PATCH RESEND 2/5] Drivers: hv: vmbus: handle various crash scenarios K. Y. Srinivasan
2016-05-01 2:21 ` [PATCH RESEND 3/5] Drivers: hv: balloon: don't crash when memory is added in non-sorted order K. Y. Srinivasan
@ 2016-05-01 2:21 ` K. Y. Srinivasan
2016-05-01 2:21 ` [PATCH RESEND 5/5] tools: hv: lsvmbus: add pci pass-through UUID K. Y. Srinivasan
3 siblings, 0 replies; 6+ messages in thread
From: K. Y. Srinivasan @ 2016-05-01 2:21 UTC (permalink / raw)
To: gregkh, linux-kernel, devel, olaf, apw, vkuznets, jasowang
Cc: K. Y. Srinivasan
From: Vitaly Kuznetsov <vkuznets@redhat.com>
We set host_specified_ha_region = true on certain request but this is a
global state which stays 'true' forever. We need to reset it when we
receive a request where ha_region is not specified. I did not see any
real issues, the bug was found by code inspection.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
drivers/hv/hv_balloon.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 43af913..df35fb7 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -1400,6 +1400,7 @@ static void balloon_onchannelcallback(void *context)
* This is a normal hot-add request specifying
* hot-add memory.
*/
+ dm->host_specified_ha_region = false;
ha_pg_range = &ha_msg->range;
dm->ha_wrk.ha_page_range = *ha_pg_range;
dm->ha_wrk.ha_region_range.page_range = 0;
--
1.7.4.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH RESEND 5/5] tools: hv: lsvmbus: add pci pass-through UUID
2016-05-01 2:21 ` [PATCH RESEND 1/5] Drivers: hv: kvp: fix IP Failover K. Y. Srinivasan
` (2 preceding siblings ...)
2016-05-01 2:21 ` [PATCH RESEND 4/5] Drivers: hv: balloon: reset host_specified_ha_region K. Y. Srinivasan
@ 2016-05-01 2:21 ` K. Y. Srinivasan
3 siblings, 0 replies; 6+ messages in thread
From: K. Y. Srinivasan @ 2016-05-01 2:21 UTC (permalink / raw)
To: gregkh, linux-kernel, devel, olaf, apw, vkuznets, jasowang
Cc: K. Y. Srinivasan
From: Vitaly Kuznetsov <vkuznets@redhat.com>
lsvmbus keeps its own copy of all VMBus UUIDs, add PCIe pass-through
device there to not report 'Unknown' for such devices.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
tools/hv/lsvmbus | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/tools/hv/lsvmbus b/tools/hv/lsvmbus
index 162a378..e8fecd6 100644
--- a/tools/hv/lsvmbus
+++ b/tools/hv/lsvmbus
@@ -35,6 +35,7 @@ vmbus_dev_dict = {
'{ba6163d9-04a1-4d29-b605-72e2ffb1dc7f}' : 'Synthetic SCSI Controller',
'{2f9bcc4a-0069-4af3-b76b-6fd0be528cda}' : 'Synthetic fiber channel adapter',
'{8c2eaf3d-32a7-4b09-ab99-bd1f1c86b501}' : 'Synthetic RDMA adapter',
+ '{44c4f61d-4444-4400-9d52-802e27ede19f}' : 'PCI Express pass-through',
'{276aacf4-ac15-426c-98dd-7521ad3f01fe}' : '[Reserved system device]',
'{f8e65716-3cb3-4a06-9a60-1889c5cccab5}' : '[Reserved system device]',
'{3375baf4-9e15-4b30-b765-67acb10d607b}' : '[Reserved system device]',
--
1.7.4.1
^ permalink raw reply [flat|nested] 6+ messages in thread