vfio/pds: Add support for dirty page tracking

In order to support dirty page tracking, the driver has to implement
the VFIO subsystem's vfio_log_ops. This includes log_start, log_stop,
and log_read_and_clear.

All of the tracker resources are allocated and dirty tracking on the
device is started during log_start. The resources are cleaned up and
dirty tracking on the device is stopped during log_stop. The dirty
pages are determined and reported during log_read_and_clear.

In order to support these callbacks admin queue commands are used.
All of the adminq queue command structures and implementations
are included as part of this patch.

PDS_LM_CMD_DIRTY_STATUS is added to query the current status of
dirty tracking on the device. This includes if it's enabled (i.e.
number of regions being tracked from the device's perspective) and
the maximum number of regions supported from the device's perspective.

PDS_LM_CMD_DIRTY_ENABLE is added to enable dirty tracking on the
specified number of regions and their iova ranges.

PDS_LM_CMD_DIRTY_DISABLE is added to disable dirty tracking for all
regions on the device.

PDS_LM_CMD_READ_SEQ and PDS_LM_CMD_DIRTY_WRITE_ACK are added to
support reading and acknowledging the currently dirtied pages.

Signed-off-by: Brett Creeley <[email protected]>
Signed-off-by: Shannon Nelson <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Reviewed-by: Shameer Kolothum <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alex Williamson <[email protected]>

Author: brettcreeley

drivers/vfio/pci/pds/Makefile

@@ -5,6 +5,7 @@ obj-$(CONFIG_PDS_VFIO_PCI) += pds-vfio-pci.o
 
 pds-vfio-pci-y := \
 	cmds.o		\
+	dirty.o		\
 	lm.o		\
 	pci_drv.o	\
 	vfio_dev.o

drivers/vfio/pci/pds/cmds.c

@@ -382,3 +382,128 @@ void pds_vfio_send_host_vf_lm_status_cmd(struct pds_vfio_pci_device *pds_vfio,
 		dev_warn(dev, "failed to send host VF migration status: %pe\n",
 			 ERR_PTR(err));
 }
+
+int pds_vfio_dirty_status_cmd(struct pds_vfio_pci_device *pds_vfio,
+			      u64 regions_dma, u8 *max_regions, u8 *num_regions)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_dirty_status = {
+			.opcode = PDS_LM_CMD_DIRTY_STATUS,
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+		},
+	};
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	union pds_core_adminq_comp comp = {};
+	int err;
+
+	dev_dbg(dev, "vf%u: Dirty status\n", pds_vfio->vf_id);
+
+	cmd.lm_dirty_status.regions_dma = cpu_to_le64(regions_dma);
+	cmd.lm_dirty_status.max_regions = *max_regions;
+
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, false);
+	if (err) {
+		dev_err(dev, "failed to get dirty status: %pe\n", ERR_PTR(err));
+		return err;
+	}
+
+	/* only support seq_ack approach for now */
+	if (!(le32_to_cpu(comp.lm_dirty_status.bmp_type_mask) &
+	      BIT(PDS_LM_DIRTY_BMP_TYPE_SEQ_ACK))) {
+		dev_err(dev, "Dirty bitmap tracking SEQ_ACK not supported\n");
+		return -EOPNOTSUPP;
+	}
+
+	*num_regions = comp.lm_dirty_status.num_regions;
+	*max_regions = comp.lm_dirty_status.max_regions;
+
+	dev_dbg(dev,
+		"Page Tracking Status command successful, max_regions: %d, num_regions: %d, bmp_type: %s\n",
+		*max_regions, *num_regions, "PDS_LM_DIRTY_BMP_TYPE_SEQ_ACK");
+
+	return 0;
+}
+
+int pds_vfio_dirty_enable_cmd(struct pds_vfio_pci_device *pds_vfio,
+			      u64 regions_dma, u8 num_regions)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_dirty_enable = {
+			.opcode = PDS_LM_CMD_DIRTY_ENABLE,
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+			.regions_dma = cpu_to_le64(regions_dma),
+			.bmp_type = PDS_LM_DIRTY_BMP_TYPE_SEQ_ACK,
+			.num_regions = num_regions,
+		},
+	};
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	union pds_core_adminq_comp comp = {};
+	int err;
+
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, false);
+	if (err) {
+		dev_err(dev, "failed dirty tracking enable: %pe\n",
+			ERR_PTR(err));
+		return err;
+	}
+
+	return 0;
+}
+
+int pds_vfio_dirty_disable_cmd(struct pds_vfio_pci_device *pds_vfio)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_dirty_disable = {
+			.opcode = PDS_LM_CMD_DIRTY_DISABLE,
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+		},
+	};
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	union pds_core_adminq_comp comp = {};
+	int err;
+
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, false);
+	if (err || comp.lm_dirty_status.num_regions != 0) {
+		/* in case num_regions is still non-zero after disable */
+		err = err ? err : -EIO;
+		dev_err(dev,
+			"failed dirty tracking disable: %pe, num_regions %d\n",
+			ERR_PTR(err), comp.lm_dirty_status.num_regions);
+		return err;
+	}
+
+	return 0;
+}
+
+int pds_vfio_dirty_seq_ack_cmd(struct pds_vfio_pci_device *pds_vfio,
+			       u64 sgl_dma, u16 num_sge, u32 offset,
+			       u32 total_len, bool read_seq)
+{
+	const char *cmd_type_str = read_seq ? "read_seq" : "write_ack";
+	union pds_core_adminq_cmd cmd = {
+		.lm_dirty_seq_ack = {
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+			.len_bytes = cpu_to_le32(total_len),
+			.off_bytes = cpu_to_le32(offset),
+			.sgl_addr = cpu_to_le64(sgl_dma),
+			.num_sge = cpu_to_le16(num_sge),
+		},
+	};
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	union pds_core_adminq_comp comp = {};
+	int err;
+
+	if (read_seq)
+		cmd.lm_dirty_seq_ack.opcode = PDS_LM_CMD_DIRTY_READ_SEQ;
+	else
+		cmd.lm_dirty_seq_ack.opcode = PDS_LM_CMD_DIRTY_WRITE_ACK;
+
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, false);
+	if (err) {
+		dev_err(dev, "failed cmd Page Tracking %s: %pe\n", cmd_type_str,
+			ERR_PTR(err));
+		return err;
+	}
+
+	return 0;
+}

drivers/vfio/pci/pds/cmds.h

@@ -13,4 +13,13 @@ int pds_vfio_get_lm_state_cmd(struct pds_vfio_pci_device *pds_vfio);
 int pds_vfio_set_lm_state_cmd(struct pds_vfio_pci_device *pds_vfio);
 void pds_vfio_send_host_vf_lm_status_cmd(struct pds_vfio_pci_device *pds_vfio,
 					 enum pds_lm_host_vf_status vf_status);
+int pds_vfio_dirty_status_cmd(struct pds_vfio_pci_device *pds_vfio,
+			      u64 regions_dma, u8 *max_regions,
+			      u8 *num_regions);
+int pds_vfio_dirty_enable_cmd(struct pds_vfio_pci_device *pds_vfio,
+			      u64 regions_dma, u8 num_regions);
+int pds_vfio_dirty_disable_cmd(struct pds_vfio_pci_device *pds_vfio);
+int pds_vfio_dirty_seq_ack_cmd(struct pds_vfio_pci_device *pds_vfio,
+			       u64 sgl_dma, u16 num_sge, u32 offset,
+			       u32 total_len, bool read_seq);
 #endif /* _CMDS_H_ */