[PATCH 4.4 018/192] [PATCH 018/135] fm10k: do not assume VF always has 1 queue

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 1340181fe435ccb8ca2f996b8680bd9566860619 ]

It is possible that the PF has not yet assigned resources to the VF.
Although rare, this could result in the VF attempting to read queues it
does not own and result in FUM or THI faults in the PF. To prevent this,
check queue 0 before we continue in init_hw_vf.

Signed-off-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
Tested-by: Krishneil Singh <Krishneil.k.singh@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/intel/fm10k/fm10k_type.h |    1 +
 drivers/net/ethernet/intel/fm10k/fm10k_vf.c   |    7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/intel/fm10k/fm10k_type.h
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_type.h
@@ -77,6 +77,7 @@ struct fm10k_hw;
 #define FM10K_PCIE_SRIOV_CTRL_VFARI		0x10
 
 #define FM10K_ERR_PARAM				-2
+#define FM10K_ERR_NO_RESOURCES			-3
 #define FM10K_ERR_REQUESTS_PENDING		-4
 #define FM10K_ERR_RESET_REQUESTED		-5
 #define FM10K_ERR_DMA_PENDING			-6
--- a/drivers/net/ethernet/intel/fm10k/fm10k_vf.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_vf.c
@@ -103,7 +103,12 @@ static s32 fm10k_init_hw_vf(struct fm10k
 	s32 err;
 	u16 i;
 
-	/* assume we always have at least 1 queue */
+	/* verify we have at least 1 queue */
+	if (!~fm10k_read_reg(hw, FM10K_TXQCTL(0)) ||
+	    !~fm10k_read_reg(hw, FM10K_RXQCTL(0)))
+		return FM10K_ERR_NO_RESOURCES;
+
+	/* determine how many queues we have */
 	for (i = 1; tqdloc0 && (i < FM10K_MAX_QUEUES_POOL); i++) {
 		/* verify the Descriptor cache offsets are increasing */
 		tqdloc = ~fm10k_read_reg(hw, FM10K_TQDLOC(i));