bnx2x: Lock PF-common resources

Use hardware locks to protect resources common to several Physical Functions. In
a virtualized environment the RTNL lock only protects a PF's driver against
the PFs sharing it's VMs with regard to device resources. Other PFs may reside
in other VMs under other OSs, and are not subject to the lock. Such resources
which were previously protected implicitly by the RTNL lock must now be
protected explicitly with dedicated HW locks.

Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
index 31a8b38ab15e..37a5c52197eb 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
@@ -882,11 +882,27 @@ static int bnx2x_get_eeprom_len(struct net_device *dev)
 	return bp->common.flash_size;
 }
 
+/* Per pf misc lock must be aquired before the per port mcp lock. Otherwise, had
+ * we done things the other way around, if two pfs from the same port would
+ * attempt to access nvram at the same time, we could run into a scenario such
+ * as:
+ * pf A takes the port lock.
+ * pf B succeeds in taking the same lock since they are from the same port.
+ * pf A takes the per pf misc lock. Performs eeprom access.
+ * pf A finishes. Unlocks the per pf misc lock.
+ * Pf B takes the lock and proceeds to perform it's own access.
+ * pf A unlocks the per port lock, while pf B is still working (!).
+ * mcp takes the per port lock and corrupts pf B's access (and/or has it's own
+ * acess corrupted by pf B).*
+ */
 static int bnx2x_acquire_nvram_lock(struct bnx2x *bp)
 {
 	int port = BP_PORT(bp);
 	int count, i;
-	u32 val = 0;
+	u32 val;
+
+	/* acquire HW lock: protect against other PFs in PF Direct Assignment */
+	bnx2x_acquire_hw_lock(bp, HW_LOCK_RESOURCE_NVRAM);
 
 	/* adjust timeout for emulation/FPGA */
 	count = BNX2X_NVRAM_TIMEOUT_COUNT;
@@ -917,7 +933,7 @@ static int bnx2x_release_nvram_lock(struct bnx2x *bp)
 {
 	int port = BP_PORT(bp);
 	int count, i;
-	u32 val = 0;
+	u32 val;
 
 	/* adjust timeout for emulation/FPGA */
 	count = BNX2X_NVRAM_TIMEOUT_COUNT;
@@ -941,6 +957,8 @@ static int bnx2x_release_nvram_lock(struct bnx2x *bp)
 		return -EBUSY;
 	}
 
+	/* release HW lock: protect against other PFs in PF Direct Assignment */
+	bnx2x_release_hw_lock(bp, HW_LOCK_RESOURCE_NVRAM);
 	return 0;
 }