sfc: Cope with permissions enforcement added to firmware for SR-IOV

* Accept EPERM in some simple cases, the following cases are handled:
1) efx_mcdi_read_assertion()
Unprivileged PCI functions aren't allowed to GET_ASSERTS.
We return success as it's up to the primary PF to deal with asserts.
2) efx_mcdi_mon_probe() in efx_ef10_probe()
Unprivileged PCI functions aren't allowed to read sensor info, and
worrying about sensor data is the primary PF's job.
3) phy_op->reconfigure() in efx_init_port() and efx_reset_up()
Unprivileged functions aren't allowed to MC_CMD_SET_LINK, they just have
to accept the settings (including flow-control, which is what
efx_init_port() is worried about) they've been given.
4) Fallback to GET_WORKAROUNDS in efx_ef10_probe()
Unprivileged PCI functions aren't allowed to set workarounds. So if
efx_mcdi_set_workaround() fails EPERM, use efx_mcdi_get_workarounds()
to find out if workaround_35388 is enabled.
5) If DRV_ATTACH gets EPERM, try without specifying fw-variant
Unprivileged PCI functions have to use a FIRMWARE_ID of 0xffffffff
(MC_CMD_FW_DONT_CARE).
6) Don't try to exit_assertion unless one had fired
Previously we called efx_mcdi_exit_assertion even if
efx_mcdi_read_assertion had received MC_CMD_GET_ASSERTS_FLAGS_NO_FAILS.
This is unnecessary, and the resulting MC_CMD_REBOOT, even if the
AFTER_ASSERTION flag made it a no-op, would fail EPERM for unprivileged
PCI functions.
So make efx_mcdi_read_assertion return whether an assert happened, and only
call efx_mcdi_exit_assertion if it has.

Signed-off-by: Shradha Shah <sshah@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/net/ethernet/sfc/mcdi_pcol.h b/drivers/net/ethernet/sfc/mcdi_pcol.h
index e028de10e1b7..4fa6eb27cc56 100644
--- a/drivers/net/ethernet/sfc/mcdi_pcol.h
+++ b/drivers/net/ethernet/sfc/mcdi_pcol.h
@@ -1875,6 +1875,8 @@
 #define          MC_CMD_FW_FULL_FEATURED 0x0
 /* enum: Prefer to use firmware with fewer features but lower latency */
 #define          MC_CMD_FW_LOW_LATENCY 0x1
+/* enum: Only this option is allowed for non-admin functions */
+#define          MC_CMD_FW_DONT_CARE  0xffffffff
 
 /* MC_CMD_DRV_ATTACH_OUT msgresponse */
 #define    MC_CMD_DRV_ATTACH_OUT_LEN 4
@@ -4087,6 +4089,27 @@
 
 
 /***********************************/
+/* MC_CMD_GET_WORKAROUNDS
+ * Read the list of all implemented and all currently enabled workarounds. The
+ * enums here must correspond with those in MC_CMD_WORKAROUND.
+ */
+#define MC_CMD_GET_WORKAROUNDS 0x59
+
+/* MC_CMD_GET_WORKAROUNDS_OUT msgresponse */
+#define    MC_CMD_GET_WORKAROUNDS_OUT_LEN 8
+/* Each workaround is represented by a single bit according to the enums below.
+ */
+#define       MC_CMD_GET_WORKAROUNDS_OUT_IMPLEMENTED_OFST 0
+#define       MC_CMD_GET_WORKAROUNDS_OUT_ENABLED_OFST 4
+/* enum: Bug 17230 work around. */
+#define          MC_CMD_GET_WORKAROUNDS_OUT_BUG17230 0x2
+/* enum: Bug 35388 work around (unsafe EVQ writes). */
+#define          MC_CMD_GET_WORKAROUNDS_OUT_BUG35388 0x4
+/* enum: Bug35017 workaround (A64 tables must be identity map) */
+#define          MC_CMD_GET_WORKAROUNDS_OUT_BUG35017 0x8
+
+
+/***********************************/
 /* MC_CMD_READ_REGS
  * Get a dump of the MCPU registers
  */