ice: Fix increasing MSI-X on VF

Increasing MSI-X value on a VF leads to invalid memory operations. This
is caused by not reallocating some arrays.

Reproducer:
  modprobe ice
  echo 0 > /sys/bus/pci/devices/$PF_PCI/sriov_drivers_autoprobe
  echo 1 > /sys/bus/pci/devices/$PF_PCI/sriov_numvfs
  echo 17 > /sys/bus/pci/devices/$VF0_PCI/sriov_vf_msix_count

Default MSI-X is 16, so 17 and above triggers this issue.

KASAN reports:

  BUG: KASAN: slab-out-of-bounds in ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice]
  Read of size 8 at addr ffff8888b937d180 by task bash/28433
  (...)

  Call Trace:
   (...)
   ? ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice]
   kasan_report+0xed/0x120
   ? ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice]
   ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice]
   ice_vsi_cfg_def+0x3360/0x4770 [ice]
   ? mutex_unlock+0x83/0xd0
   ? __pfx_ice_vsi_cfg_def+0x10/0x10 [ice]
   ? __pfx_ice_remove_vsi_lkup_fltr+0x10/0x10 [ice]
   ice_vsi_cfg+0x7f/0x3b0 [ice]
   ice_vf_reconfig_vsi+0x114/0x210 [ice]
   ice_sriov_set_msix_vec_count+0x3d0/0x960 [ice]
   sriov_vf_msix_count_store+0x21c/0x300
   (...)

  Allocated by task 28201:
   (...)
   ice_vsi_cfg_def+0x1c8e/0x4770 [ice]
   ice_vsi_cfg+0x7f/0x3b0 [ice]
   ice_vsi_setup+0x179/0xa30 [ice]
   ice_sriov_configure+0xcaa/0x1520 [ice]
   sriov_numvfs_store+0x212/0x390
   (...)

To fix it, use ice_vsi_rebuild() instead of ice_vf_reconfig_vsi(). This
causes the required arrays to be reallocated taking the new queue count
into account (ice_vsi_realloc_stat_arrays()). Set req_txq and req_rxq
before ice_vsi_rebuild(), so that realloc uses the newly set queue
count.

Additionally, ice_vsi_rebuild() does not remove VSI filters
(ice_fltr_remove_all()), so ice_vf_init_host_cfg() is no longer
necessary.
Reported-by: Jacob Keller <jacob.e.keller@intel.com>
Fixes: 2a2cb4c6 ("ice: replace ice_vf_recreate_vsi() with ice_vf_reconfig_vsi()")
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Marcin Szycik <marcin.szycik@linux.intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_sriov.c

@@ -1121,7 +1121,10 @@ int ice_sriov_set_msix_vec_count(struct pci_dev *vf_dev, int msix_vec_count)
 	if (vf->first_vector_idx < 0)
 		goto unroll;
 
-	if (ice_vf_reconfig_vsi(vf) || ice_vf_init_host_cfg(vf, vsi)) {
+	vsi->req_txq = queues;
+	vsi->req_rxq = queues;
+
+	if (ice_vsi_rebuild(vsi, ICE_VSI_FLAG_NO_INIT)) {
 		/* Try to rebuild with previous values */
 		needs_rebuild = true;
 		goto unroll;
@@ -1150,8 +1153,10 @@ int ice_sriov_set_msix_vec_count(struct pci_dev *vf_dev, int msix_vec_count)
 	}
 
 	if (needs_rebuild) {
-		ice_vf_reconfig_vsi(vf);
-		ice_vf_init_host_cfg(vf, vsi);
+		vsi->req_txq = prev_queues;
+		vsi->req_rxq = prev_queues;
+
+		ice_vsi_rebuild(vsi, ICE_VSI_FLAG_NO_INIT);
 	}
 
 	ice_ena_vf_mappings(vf);

drivers/net/ethernet/intel/ice/ice_vf_lib.c

@@ -256,7 +256,7 @@ static void ice_vf_pre_vsi_rebuild(struct ice_vf *vf)
  *
  * It brings the VSI down and then reconfigures it with the hardware.
  */
-int ice_vf_reconfig_vsi(struct ice_vf *vf)
+static int ice_vf_reconfig_vsi(struct ice_vf *vf)
 {
 	struct ice_vsi *vsi = ice_get_vf_vsi(vf);
 	struct ice_pf *pf = vf->pf;

drivers/net/ethernet/intel/ice/ice_vf_lib_private.h

@@ -23,7 +23,6 @@
 #warning "Only include ice_vf_lib_private.h in CONFIG_PCI_IOV virtualization files"
 #endif
 
-int ice_vf_reconfig_vsi(struct ice_vf *vf);
 void ice_initialize_vf_entry(struct ice_vf *vf);
 void ice_dis_vf_qs(struct ice_vf *vf);
 int ice_check_vf_init(struct ice_vf *vf);