net/mlx5_core: Add base sriov support

This patch adds SRIOV base support for mlx5 supported devices. The same
driver is used for both PFs and VFs; VFs are identified by the driver
through the flag MLX5_PCI_DEV_IS_VF added to the pci table entries.
Virtual functions are created as usual through writing a value to the
sriov_numvs sysfs file of the PF device. Upon instantiating VFs, they will
all be probed by the driver on the hypervisor. One can gracefully unbind
them through /sys/bus/pci/drivers/mlx5_core/unbind.

mlx5_wait_for_vf_pages() was added to ensure that when a VF dies without
executing proper teardown, the hypervisor driver waits till all of the
pages that were allocated at the hypervisor to maintain its operation
are returned.

In order for the VF to be operational, the PF needs to call enable_hca
for it. This can be done before the VFs are created through a call to
pci_enable_sriov.

If the there are VFs assigned to a VMs when the driver of the PF is
unloaded, all the VF will experience system error and PF driver unloads
cleanly; in this case pci_disable_sriov is not called and the devices
will show when running lspci. Once the PF driver is reloaded, it will
sync its data structures which maintain state on its VFs.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 221 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/sriov.c b/drivers/net/ethernet/mellanox/mlx5/core/sriov.c
new file mode 100644
index 0000000..19a4324
--- /dev/null
+++ b/drivers/net/ethernet/mellanox/mlx5/core/sriov.c
@@ -0,0 +1,221 @@
+/*
+ * Copyright (c) 2014, Mellanox Technologies inc.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/pci.h>
+#include <linux/mlx5/driver.h>
+#include "mlx5_core.h"
+
+static void enable_vfs(struct mlx5_core_dev *dev, int num_vfs)
+{
+	struct mlx5_core_sriov *sriov = &dev->priv.sriov;
+	int err;
+	int vf;
+
+	for (vf = 1; vf <= num_vfs; vf++) {
+		err = mlx5_core_enable_hca(dev, vf);
+		if (err) {
+			mlx5_core_warn(dev, "failed to enable VF %d\n", vf - 1);
+		} else {
+			sriov->vfs_ctx[vf - 1].enabled = 1;
+			mlx5_core_dbg(dev, "successfully enabled VF %d\n", vf - 1);
+		}
+	}
+}
+
+static void disable_vfs(struct mlx5_core_dev *dev, int num_vfs)
+{
+	struct mlx5_core_sriov *sriov = &dev->priv.sriov;
+	int vf;
+
+	for (vf = 1; vf <= num_vfs; vf++) {
+		if (sriov->vfs_ctx[vf - 1].enabled) {
+			if (mlx5_core_disable_hca(dev, vf))
+				mlx5_core_warn(dev, "failed to disable VF %d\n", vf - 1);
+			else
+				sriov->vfs_ctx[vf - 1].enabled = 0;
+		}
+	}
+}
+
+static int mlx5_core_create_vfs(struct pci_dev *pdev, int num_vfs)
+{
+	struct mlx5_core_dev *dev  = pci_get_drvdata(pdev);
+	int err;
+
+	if (pci_num_vf(pdev))
+		pci_disable_sriov(pdev);
+
+	enable_vfs(dev, num_vfs);
+
+	err = pci_enable_sriov(pdev, num_vfs);
+	if (err) {
+		dev_warn(&pdev->dev, "enable sriov failed %d\n", err);
+		goto ex;
+	}
+
+	return 0;
+
+ex:
+	disable_vfs(dev, num_vfs);
+	return err;
+}
+
+static int mlx5_core_sriov_enable(struct pci_dev *pdev, int num_vfs)
+{
+	struct mlx5_core_dev *dev  = pci_get_drvdata(pdev);
+	struct mlx5_core_sriov *sriov = &dev->priv.sriov;
+	int err;
+
+	kfree(sriov->vfs_ctx);
+	sriov->vfs_ctx = kcalloc(num_vfs, sizeof(*sriov->vfs_ctx), GFP_ATOMIC);
+	if (!sriov->vfs_ctx)
+		return -ENOMEM;
+
+	sriov->enabled_vfs = num_vfs;
+	err = mlx5_core_create_vfs(pdev, num_vfs);
+	if (err) {
+		kfree(sriov->vfs_ctx);
+		sriov->vfs_ctx = NULL;
+		return err;
+	}
+
+	return 0;
+}
+
+static void mlx5_core_init_vfs(struct mlx5_core_dev *dev, int num_vfs)
+{
+	struct mlx5_core_sriov *sriov = &dev->priv.sriov;
+
+	sriov->num_vfs = num_vfs;
+}
+
+static void mlx5_core_cleanup_vfs(struct mlx5_core_dev *dev)
+{
+	struct mlx5_core_sriov *sriov;
+
+	sriov = &dev->priv.sriov;
+	disable_vfs(dev, sriov->num_vfs);
+
+	if (mlx5_wait_for_vf_pages(dev))
+		mlx5_core_warn(dev, "timeout claiming VFs pages\n");
+
+	sriov->num_vfs = 0;
+}
+
+int mlx5_core_sriov_configure(struct pci_dev *pdev, int num_vfs)
+{
+	struct mlx5_core_dev *dev  = pci_get_drvdata(pdev);
+	struct mlx5_core_sriov *sriov = &dev->priv.sriov;
+	int err;
+
+	mlx5_core_dbg(dev, "requsted num_vfs %d\n", num_vfs);
+	if (!mlx5_core_is_pf(dev))
+		return -EPERM;
+
+	mlx5_core_cleanup_vfs(dev);
+
+	if (!num_vfs) {
+		kfree(sriov->vfs_ctx);
+		sriov->vfs_ctx = NULL;
+		if (!pci_vfs_assigned(pdev))
+			pci_disable_sriov(pdev);
+		else
+			pr_info("unloading PF driver while leaving orphan VFs\n");
+
+		return 0;
+	}
+
+	err = mlx5_core_sriov_enable(pdev, num_vfs);
+	if (err) {
+		dev_warn(&pdev->dev, "mlx5_core_sriov_enable failed %d\n", err);
+		return err;
+	}
+
+	mlx5_core_init_vfs(dev, num_vfs);
+
+	return num_vfs;
+}
+
+static int sync_required(struct pci_dev *pdev)
+{
+	struct mlx5_core_dev *dev  = pci_get_drvdata(pdev);
+	struct mlx5_core_sriov *sriov = &dev->priv.sriov;
+	int cur_vfs = pci_num_vf(pdev);
+
+	if (cur_vfs != sriov->num_vfs) {
+		pr_info("current VFs %d, registered %d - sync needed\n", cur_vfs, sriov->num_vfs);
+		return 1;
+	}
+
+	return 0;
+}
+
+int mlx5_sriov_init(struct mlx5_core_dev *dev)
+{
+	struct mlx5_core_sriov *sriov = &dev->priv.sriov;
+	struct pci_dev *pdev = dev->pdev;
+	int cur_vfs;
+
+	if (!mlx5_core_is_pf(dev))
+		return 0;
+
+	if (!sync_required(dev->pdev))
+		return 0;
+
+	cur_vfs = pci_num_vf(pdev);
+	sriov->vfs_ctx = kcalloc(cur_vfs, sizeof(*sriov->vfs_ctx), GFP_KERNEL);
+	if (!sriov->vfs_ctx)
+		return -ENOMEM;
+
+	sriov->enabled_vfs = cur_vfs;
+
+	mlx5_core_init_vfs(dev, cur_vfs);
+
+	enable_vfs(dev, cur_vfs);
+
+	return 0;
+}
+
+int mlx5_sriov_cleanup(struct mlx5_core_dev *dev)
+{
+	struct pci_dev *pdev = dev->pdev;
+	int err;
+
+	if (!mlx5_core_is_pf(dev))
+		return 0;
+
+	err = mlx5_core_sriov_configure(pdev, 0);
+	if (err)
+		return err;
+
+	return 0;
+}