[dpdk-dev] [PATCH 18/53] net/qede/base: avoid possible race condition
Rasesh Mody
rasesh.mody at cavium.com
Tue Sep 19 03:29:58 CEST 2017
There's a possible race in multiple VF scenarios for base driver users
that use the optional APIs ecore_iov_pf_get_and_clear_pending_events,
ecore_iov_pf_add_pending_events. If the client doesn't synchronize the two
calls, it's possible for the PF to clear a VF pending message indication
without ever getting it [as 'get & clear' isn't atomic], leading to VF
timeout on the command.
The solution is to switch into a per-VF indication rather than having a
bitfield for the various VFs with pending events. As part of the solution,
the setting/clearing of the indications is done internally by base driver.
As a result, ecore_iov_pf_add_pending_events is no longer needed and
ecore_iov_pf_get_and_clear_pending_events loses the 'and_clear' from its
name as its now a proper getter.
A VF would be considered 'pending' [I.e., get_pending_events() should
have '1' for it in its bitfield] beginning with the PF's base driver
recognizing a message sent by that VF [in SP_DPC] and ending only when
that VF message is processed.
Signed-off-by: Rasesh Mody <rasesh.mody at cavium.com>
---
drivers/net/qede/base/ecore_iov_api.h | 16 +++--------
drivers/net/qede/base/ecore_sriov.c | 47 ++++++++++++++++++---------------
drivers/net/qede/base/ecore_sriov.h | 4 ++-
3 files changed, 33 insertions(+), 34 deletions(-)
diff --git a/drivers/net/qede/base/ecore_iov_api.h b/drivers/net/qede/base/ecore_iov_api.h
index 4fce6b6..4ec6217 100644
--- a/drivers/net/qede/base/ecore_iov_api.h
+++ b/drivers/net/qede/base/ecore_iov_api.h
@@ -345,21 +345,13 @@ struct ecore_public_vf_info*
u16 vfid, bool b_enabled_only);
/**
- * @brief Set pending events bitmap for given @vfid
- *
- * @param p_hwfn
- * @param vfid
- */
-void ecore_iov_pf_add_pending_events(struct ecore_hwfn *p_hwfn, u8 vfid);
-
-/**
- * @brief Copy pending events bitmap in @events and clear
- * original copy of events
+ * @brief fills a bitmask of all VFs which have pending unhandled
+ * messages.
*
* @param p_hwfn
*/
-void ecore_iov_pf_get_and_clear_pending_events(struct ecore_hwfn *p_hwfn,
- u64 *events);
+void ecore_iov_pf_get_pending_events(struct ecore_hwfn *p_hwfn,
+ u64 *events);
/**
* @brief Copy VF's message to PF's buffer
diff --git a/drivers/net/qede/base/ecore_sriov.c b/drivers/net/qede/base/ecore_sriov.c
index b8e03d0..7ac533e 100644
--- a/drivers/net/qede/base/ecore_sriov.c
+++ b/drivers/net/qede/base/ecore_sriov.c
@@ -3755,8 +3755,7 @@ static enum _ecore_status_t ecore_iov_vf_flr_poll(struct ecore_hwfn *p_hwfn,
ack_vfs[vfid / 32] |= (1 << (vfid % 32));
p_hwfn->pf_iov_info->pending_flr[rel_vf_id / 64] &=
~(1ULL << (rel_vf_id % 64));
- p_hwfn->pf_iov_info->pending_events[rel_vf_id / 64] &=
- ~(1ULL << (rel_vf_id % 64));
+ p_vf->vf_mbx.b_pending_msg = false;
}
return rc;
@@ -3886,12 +3885,22 @@ void ecore_iov_process_mbx_req(struct ecore_hwfn *p_hwfn,
mbx = &p_vf->vf_mbx;
/* ecore_iov_process_mbx_request */
- DP_VERBOSE(p_hwfn,
- ECORE_MSG_IOV,
- "VF[%02x]: Processing mailbox message\n", p_vf->abs_vf_id);
+#ifndef CONFIG_ECORE_SW_CHANNEL
+ if (!mbx->b_pending_msg) {
+ DP_NOTICE(p_hwfn, true,
+ "VF[%02x]: Trying to process mailbox message when none is pending\n",
+ p_vf->abs_vf_id);
+ return;
+ }
+ mbx->b_pending_msg = false;
+#endif
mbx->first_tlv = mbx->req_virt->first_tlv;
+ DP_VERBOSE(p_hwfn, ECORE_MSG_IOV,
+ "VF[%02x]: Processing mailbox message [type %04x]\n",
+ p_vf->abs_vf_id, mbx->first_tlv.tl.type);
+
OSAL_IOV_VF_MSG_TYPE(p_hwfn,
p_vf->relative_vf_id,
mbx->first_tlv.tl.type);
@@ -4016,26 +4025,20 @@ void ecore_iov_process_mbx_req(struct ecore_hwfn *p_hwfn,
#endif
}
-void ecore_iov_pf_add_pending_events(struct ecore_hwfn *p_hwfn, u8 vfid)
+void ecore_iov_pf_get_pending_events(struct ecore_hwfn *p_hwfn,
+ u64 *events)
{
- u64 add_bit = 1ULL << (vfid % 64);
+ int i;
- /* TODO - add locking mechanisms [no atomics in ecore, so we can't
- * add the lock inside the ecore_pf_iov struct].
- */
- p_hwfn->pf_iov_info->pending_events[vfid / 64] |= add_bit;
-}
+ OSAL_MEM_ZERO(events, sizeof(u64) * ECORE_VF_ARRAY_LENGTH);
-void ecore_iov_pf_get_and_clear_pending_events(struct ecore_hwfn *p_hwfn,
- u64 *events)
-{
- u64 *p_pending_events = p_hwfn->pf_iov_info->pending_events;
+ ecore_for_each_vf(p_hwfn, i) {
+ struct ecore_vf_info *p_vf;
- /* TODO - Take a lock */
- OSAL_MEMCPY(events, p_pending_events,
- sizeof(u64) * ECORE_VF_ARRAY_LENGTH);
- OSAL_MEMSET(p_pending_events, 0,
- sizeof(u64) * ECORE_VF_ARRAY_LENGTH);
+ p_vf = &p_hwfn->pf_iov_info->vfs_array[i];
+ if (p_vf->vf_mbx.b_pending_msg)
+ events[i / 64] |= 1ULL << (i % 64);
+ }
}
static struct ecore_vf_info *
@@ -4069,6 +4072,8 @@ static enum _ecore_status_t ecore_sriov_vfpf_msg(struct ecore_hwfn *p_hwfn,
*/
p_vf->vf_mbx.pending_req = (((u64)vf_msg->hi) << 32) | vf_msg->lo;
+ p_vf->vf_mbx.b_pending_msg = true;
+
return OSAL_PF_VF_MSG(p_hwfn, p_vf->relative_vf_id);
}
diff --git a/drivers/net/qede/base/ecore_sriov.h b/drivers/net/qede/base/ecore_sriov.h
index d190126..8923730 100644
--- a/drivers/net/qede/base/ecore_sriov.h
+++ b/drivers/net/qede/base/ecore_sriov.h
@@ -45,6 +45,9 @@ struct ecore_iov_vf_mbx {
/* Address in VF where a pending message is located */
dma_addr_t pending_req;
+ /* Message from VF awaits handling */
+ bool b_pending_msg;
+
u8 *offset;
#ifdef CONFIG_ECORE_SW_CHANNEL
@@ -168,7 +171,6 @@ struct ecore_vf_info {
*/
struct ecore_pf_iov {
struct ecore_vf_info vfs_array[E4_MAX_NUM_VFS];
- u64 pending_events[ECORE_VF_ARRAY_LENGTH];
u64 pending_flr[ECORE_VF_ARRAY_LENGTH];
#ifndef REMOVE_DBG
--
1.7.10.3
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