[RFC PATCH v2 vfio 5/7] vfio/pds: Add support for dirty page tracking

Brett Creeley
2022-12-14T23:25:01Z

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 <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
---
drivers/vfio/pci/pds/Makefile | 1 +
drivers/vfio/pci/pds/cmds.c | 143 +++++++++
drivers/vfio/pci/pds/cmds.h | 15 +
drivers/vfio/pci/pds/dirty.c | 541 ++++++++++++++++++++++++++++++++
drivers/vfio/pci/pds/dirty.h | 48 +++
drivers/vfio/pci/pds/lm.h | 10 +
drivers/vfio/pci/pds/vfio_dev.c | 9 +
drivers/vfio/pci/pds/vfio_dev.h | 2 +
include/linux/pds/pds_lm.h | 173 ++++++++++
9 files changed, 942 insertions(+)
create mode 100644 drivers/vfio/pci/pds/dirty.c
create mode 100644 drivers/vfio/pci/pds/dirty.h

diff --git a/drivers/vfio/pci/pds/Makefile b/drivers/vfio/pci/pds/Makefile
index b4980323cff4..103169dcb746 100644
--- a/drivers/vfio/pci/pds/Makefile
+++ b/drivers/vfio/pci/pds/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_PDS_VFIO_PCI) += pds_vfio.o
pds_vfio-y := \
aux_drv.o \
cmds.o \
+ dirty.o \
lm.o \
pci_drv.o \
vfio_dev.o
diff --git a/drivers/vfio/pci/pds/cmds.c b/drivers/vfio/pci/pds/cmds.c
index 11823d824ccc..3ebd46fd6b57 100644
--- a/drivers/vfio/pci/pds/cmds.c
+++ b/drivers/vfio/pci/pds/cmds.c
@@ -340,3 +340,146 @@ pds_vfio_send_host_vf_lm_status_cmd(struct pds_vfio_pci_device *pds_vfio,
dev_warn(&pdev->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)
+{
+ struct pds_auxiliary_dev *padev = pds_vfio->vfio_aux->padev;
+ struct pds_lm_dirty_status_cmd cmd = {
+ .opcode = PDS_LM_CMD_DIRTY_STATUS,
+ .vf_id = cpu_to_le16(pds_vfio->vf_id),
+ };
+ struct pds_lm_dirty_status_comp comp = {0};
+ struct pci_dev *pdev = pds_vfio->pdev;
+ int err;
+
+ dev_dbg(&pdev->dev, "vf%u: Dirty status\n", pds_vfio->vf_id);
+
+ cmd.regions_dma = cpu_to_le64(regions_dma);
+ cmd.max_regions = *max_regions;
+
+ err = padev->ops->adminq_cmd(padev,
+ (union pds_core_adminq_cmd *)&cmd,
+ sizeof(cmd),
+ (union pds_core_adminq_comp *)&comp,
+ 0);
+ if (err) {
+ dev_err(&pdev->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.bmp_type_mask) &
+ BIT(PDS_LM_DIRTY_BMP_TYPE_SEQ_ACK))) {
+ dev_err(&pdev->dev, "Dirty bitmap tracking SEQ_ACK not supported\n");
+ return -EOPNOTSUPP;
+ }
+
+ *num_regions = comp.num_regions;
+ *max_regions = comp.max_regions;
+
+ dev_dbg(&pdev->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)
+{
+ struct pds_auxiliary_dev *padev = pds_vfio->vfio_aux->padev;
+ struct pds_lm_dirty_enable_cmd cmd = {
+ .opcode = PDS_LM_CMD_DIRTY_ENABLE,
+ .vf_id = cpu_to_le16(pds_vfio->vf_id),
+ };
+ struct pds_lm_dirty_status_comp comp = {0};
+ struct pci_dev *pdev = pds_vfio->pdev;
+ int err;
+
+ cmd.regions_dma = cpu_to_le64(regions_dma);
+ cmd.bmp_type = PDS_LM_DIRTY_BMP_TYPE_SEQ_ACK;
+ cmd.num_regions = num_regions;
+
+ err = padev->ops->adminq_cmd(padev,
+ (union pds_core_adminq_cmd *)&cmd,
+ sizeof(cmd),
+ (union pds_core_adminq_comp *)&comp,
+ 0);
+ if (err) {
+ dev_err(&pdev->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)
+{
+ struct pds_auxiliary_dev *padev = pds_vfio->vfio_aux->padev;
+ struct pds_lm_dirty_disable_cmd cmd = {
+ .opcode = PDS_LM_CMD_DIRTY_DISABLE,
+ .vf_id = cpu_to_le16(pds_vfio->vf_id),
+ };
+ struct pds_lm_dirty_status_comp comp = {0};
+ struct pci_dev *pdev = pds_vfio->pdev;
+ int err;
+
+ err = padev->ops->adminq_cmd(padev,
+ (union pds_core_adminq_cmd *)&cmd,
+ sizeof(cmd),
+ (union pds_core_adminq_comp *)&comp,
+ 0);
+ if (err || comp.num_regions != 0) {
+ /* in case num_regions is still non-zero after disable */
+ err = err ? err : -EIO;
+ dev_err(&pdev->dev, "failed dirty tracking disable: %pe, num_regions %d\n",
+ ERR_PTR(err), comp.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";
+ struct pds_auxiliary_dev *padev = pds_vfio->vfio_aux->padev;
+ struct pds_lm_dirty_seq_ack_cmd cmd = {
+ .vf_id = cpu_to_le16(pds_vfio->vf_id),
+ };
+ struct pci_dev *pdev = pds_vfio->pdev;
+ struct pds_lm_comp comp = {0};
+ int err;
+
+ if (read_seq)
+ cmd.opcode = PDS_LM_CMD_DIRTY_READ_SEQ;
+ else
+ cmd.opcode = PDS_LM_CMD_DIRTY_WRITE_ACK;
+
+ cmd.sgl_addr = cpu_to_le64(sgl_dma);
+ cmd.num_sge = cpu_to_le16(num_sge);
+ cmd.len_bytes = cpu_to_le32(total_len);
+ cmd.off_bytes = cpu_to_le32(offset);
+
+ err = padev->ops->adminq_cmd(padev,
+ (union pds_core_adminq_cmd *)&cmd,
+ sizeof(cmd),
+ (union pds_core_adminq_comp *)&comp,
+ 0);
+ if (err) {
+ dev_err(&pdev->dev, "failed cmd Page Tracking %s: %pe\n",
+ cmd_type_str, ERR_PTR(err));
+ return err;
+ }
+
+ return 0;
+}
diff --git a/drivers/vfio/pci/pds/cmds.h b/drivers/vfio/pci/pds/cmds.h
index 5f9ac45ee5a3..d4d53fcbb739 100644
--- a/drivers/vfio/pci/pds/cmds.h
+++ b/drivers/vfio/pci/pds/cmds.h
@@ -4,6 +4,8 @@
#ifndef _CMDS_H_
#define _CMDS_H_

+#include <linux/types.h>
+
#include <linux/pds/pds_lm.h>

struct pds_vfio_pci_device;
@@ -25,5 +27,18 @@ 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_ */
diff --git a/drivers/vfio/pci/pds/dirty.c b/drivers/vfio/pci/pds/dirty.c
new file mode 100644
index 000000000000..b95478844cc4
--- /dev/null
+++ b/drivers/vfio/pci/pds/dirty.c
@@ -0,0 +1,541 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2022 Pensando Systems, Inc */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/interval_tree.h>
+#include <linux/vfio.h>
+
+#include <linux/pds/pds_intr.h>
+#include <linux/pds/pds_core_if.h>
+#include <linux/pds/pds_adminq.h>
+#include <linux/pds/pds_auxbus.h>
+
+#include "cmds.h"
+#include "dirty.h"
+#include "vfio_dev.h"
+
+#define READ_SEQ true
+#define WRITE_ACK false
+
+bool
+pds_vfio_dirty_is_enabled(struct pds_vfio_pci_device *pds_vfio)
+{
+ return pds_vfio->dirty.is_enabled;
+}
+
+void
+pds_vfio_dirty_set_enabled(struct pds_vfio_pci_device *pds_vfio)
+{
+ pds_vfio->dirty.is_enabled = true;
+}
+
+void
+pds_vfio_dirty_set_disabled(struct pds_vfio_pci_device *pds_vfio)
+{
+ pds_vfio->dirty.is_enabled = false;
+}
+
+static void
+pds_vfio_print_guest_region_info(struct pds_vfio_pci_device *pds_vfio,
+ u8 max_regions)
+{
+ int len = max_regions * sizeof(struct pds_lm_dirty_region_info);
+ struct pds_lm_dirty_region_info *region_info;
+ struct pci_dev *pdev = pds_vfio->pdev;
+ dma_addr_t regions_dma;
+ u8 num_regions;
+ int err;
+
+ region_info = kcalloc(max_regions,
+ sizeof(struct pds_lm_dirty_region_info),
+ GFP_KERNEL);
+ if (!region_info)
+ return;
+
+ regions_dma = dma_map_single(pds_vfio->coredev, region_info, len,
+ DMA_FROM_DEVICE);
+ if (dma_mapping_error(pds_vfio->coredev, regions_dma)) {
+ kfree(region_info);
+ return;
+ }
+
+ err = pds_vfio_dirty_status_cmd(pds_vfio, regions_dma,
+ &max_regions, &num_regions);
+ dma_unmap_single(pds_vfio->coredev, regions_dma, len, DMA_FROM_DEVICE);
+
+ if (!err) {
+ int i;
+
+ for (i = 0; i < num_regions; i++)
+ dev_dbg(&pdev->dev, "region_info[%d]: dma_base 0x%llx page_count %u page_size_log2 %u\n",
+ i, le64_to_cpu(region_info[i].dma_base),
+ le32_to_cpu(region_info[i].page_count),
+ region_info[i].page_size_log2);
+ }
+
+ kfree(region_info);
+}
+
+static int
+pds_vfio_dirty_alloc_bitmaps(struct pds_vfio_dirty *dirty,
+ u32 nbits)
+{
+ unsigned long *host_seq_bmp, *host_ack_bmp;
+
+ host_seq_bmp = bitmap_zalloc(nbits, GFP_KERNEL);
+ if (!host_seq_bmp)
+ return -ENOMEM;
+
+ host_ack_bmp = bitmap_zalloc(nbits, GFP_KERNEL);
+ if (!host_ack_bmp) {
+ bitmap_free(host_seq_bmp);
+ return -ENOMEM;
+ }
+
+ dirty->host_seq.bmp = host_seq_bmp;
+ dirty->host_ack.bmp = host_ack_bmp;
+
+ return 0;
+}
+
+static void
+pds_vfio_dirty_free_bitmaps(struct pds_vfio_dirty *dirty)
+{
+ if (dirty->host_seq.bmp)
+ bitmap_free(dirty->host_seq.bmp);
+ if (dirty->host_ack.bmp)
+ bitmap_free(dirty->host_ack.bmp);
+
+ dirty->host_seq.bmp = NULL;
+ dirty->host_ack.bmp = NULL;
+}
+
+static void
+__pds_vfio_dirty_free_sgl(struct pds_vfio_pci_device *pds_vfio,
+ struct pds_vfio_bmp_info *bmp_info)
+{
+ dma_free_coherent(pds_vfio->coredev,
+ bmp_info->num_sge * sizeof(*bmp_info->sgl),
+ bmp_info->sgl, bmp_info->sgl_addr);
+
+ bmp_info->num_sge = 0;
+ bmp_info->sgl = NULL;
+ bmp_info->sgl_addr = 0;
+}
+
+static void
+pds_vfio_dirty_free_sgl(struct pds_vfio_pci_device *pds_vfio)
+{
+ if (pds_vfio->dirty.host_seq.sgl)
+ __pds_vfio_dirty_free_sgl(pds_vfio,
+ &pds_vfio->dirty.host_seq);
+ if (pds_vfio->dirty.host_ack.sgl)
+ __pds_vfio_dirty_free_sgl(pds_vfio,
+ &pds_vfio->dirty.host_ack);
+}
+
+static int
+__pds_vfio_dirty_alloc_sgl(struct pds_vfio_pci_device *pds_vfio,
+ struct pds_vfio_bmp_info *bmp_info,
+ u32 page_count)
+{
+ struct pds_lm_sg_elem *sgl;
+ dma_addr_t sgl_addr;
+ u32 max_sge;
+
+ max_sge = DIV_ROUND_UP(page_count, PAGE_SIZE * 8);
+
+ sgl = dma_alloc_coherent(pds_vfio->coredev,
+ max_sge * sizeof(*sgl), &sgl_addr,
+ GFP_KERNEL);
+ if (!sgl)
+ return -ENOMEM;
+
+ bmp_info->sgl = sgl;
+ bmp_info->num_sge = max_sge;
+ bmp_info->sgl_addr = sgl_addr;
+
+ return 0;
+}
+
+static int
+pds_vfio_dirty_alloc_sgl(struct pds_vfio_pci_device *pds_vfio,
+ u32 page_count)
+{
+ struct pds_vfio_dirty *dirty = &pds_vfio->dirty;
+ int err;
+
+ err = __pds_vfio_dirty_alloc_sgl(pds_vfio,
+ &dirty->host_seq,
+ page_count);
+ if (err)
+ return err;
+
+ err = __pds_vfio_dirty_alloc_sgl(pds_vfio,
+ &dirty->host_ack,
+ page_count);
+ if (err) {
+ __pds_vfio_dirty_free_sgl(pds_vfio, &dirty->host_seq);
+ return err;
+ }
+
+ return 0;
+}
+
+static int
+pds_vfio_dirty_enable(struct pds_vfio_pci_device *pds_vfio,
+ struct rb_root_cached *ranges, u32 nnodes,
+ u64 *page_size)
+{
+ struct pds_vfio_dirty *dirty = &pds_vfio->dirty;
+ u64 region_start, region_size, region_page_size;
+ struct pds_lm_dirty_region_info *region_info;
+ struct interval_tree_node *node = NULL;
+ struct pci_dev *pdev = pds_vfio->pdev;
+ u8 max_regions = 0, num_regions;
+ dma_addr_t regions_dma = 0;
+ u32 num_ranges = nnodes;
+ u32 page_count;
+ u16 len;
+ int err;
+
+ dev_dbg(&pdev->dev, "vf%u: Start dirty page tracking\n", pds_vfio->vf_id);
+
+ if (pds_vfio_dirty_is_enabled(pds_vfio))
+ return -EINVAL;
+
+ pds_vfio_dirty_set_enabled(pds_vfio);
+
+ /* find if dirty tracking is disabled, i.e. num_regions == 0 */
+ err = pds_vfio_dirty_status_cmd(pds_vfio, 0, &max_regions, &num_regions);
+ if (num_regions) {
+ dev_err(&pdev->dev, "Dirty tracking already enabled for %d regions\n",
+ num_regions);
+ err = -EEXIST;
+ goto err_out;
+ } else if (!max_regions) {
+ dev_err(&pdev->dev, "Device doesn't support dirty tracking, max_regions %d\n",
+ max_regions);
+ err = -EOPNOTSUPP;
+ goto err_out;
+ } else if (err) {
+ dev_err(&pdev->dev, "Failed to get dirty status, err %pe\n",
+ ERR_PTR(err));
+ goto err_out;
+ }
+
+ /* Only support 1 region for now. If there are any large gaps in the
+ * VM's address regions, then this would be a waste of memory as we are
+ * generating 2 bitmaps (ack/seq) from the min address to the max
+ * address of the VM's address regions. In the future, if we support
+ * more than one region in the device/driver we can split the bitmaps
+ * on the largest address region gaps. We can do this split up to the
+ * max_regions times returned from the dirty_status command.
+ */
+ max_regions = 1;
+ if (num_ranges > max_regions) {
+ vfio_combine_iova_ranges(ranges, nnodes, max_regions);
+ num_ranges = max_regions;
+ }
+
+ node = interval_tree_iter_first(ranges, 0, ULONG_MAX);
+ if (!node) {
+ err = -EINVAL;
+ goto err_out;
+ }
+
+ region_size = node->last - node->start + 1;
+ region_start = node->start;
+ region_page_size = *page_size;
+
+ len = sizeof(*region_info);
+ region_info = kzalloc(len, GFP_KERNEL);
+ if (!region_info) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+
+ page_count = DIV_ROUND_UP(region_size, region_page_size);
+
+ region_info->dma_base = cpu_to_le64(region_start);
+ region_info->page_count = cpu_to_le32(page_count);
+ region_info->page_size_log2 = ilog2(region_page_size);
+
+ regions_dma = dma_map_single(pds_vfio->coredev, (void *)region_info, len,
+ DMA_BIDIRECTIONAL);
+ if (dma_mapping_error(pds_vfio->coredev, regions_dma)) {
+ err = -ENOMEM;
+ kfree(region_info);
+ goto err_out;
+ }
+
+ err = pds_vfio_dirty_enable_cmd(pds_vfio, regions_dma, max_regions);
+ dma_unmap_single(pds_vfio->coredev, regions_dma, len, DMA_BIDIRECTIONAL);
+ /* page_count might be adjusted by the device,
+ * update it before freeing region_info DMA
+ */
+ page_count = le32_to_cpu(region_info->page_count);
+
+ dev_dbg(&pdev->dev, "region_info: regions_dma 0x%llx dma_base 0x%llx page_count %u page_size_log2 %u\n",
+ regions_dma, region_start, page_count, (u8)ilog2(region_page_size));
+
+ kfree(region_info);
+ if (err)
+ goto err_out;
+
+ err = pds_vfio_dirty_alloc_bitmaps(dirty, page_count);
+ if (err) {
+ dev_err(&pdev->dev, "Failed to alloc dirty bitmaps: %pe\n",
+ ERR_PTR(err));
+ goto err_out;
+ }
+
+ err = pds_vfio_dirty_alloc_sgl(pds_vfio, page_count);
+ if (err) {
+ dev_err(&pdev->dev, "Failed to alloc dirty sg lists: %pe\n",
+ ERR_PTR(err));
+ goto err_free_bitmaps;
+ }
+
+ dirty->region_start = region_start;
+ dirty->region_size = region_size;
+ dirty->region_page_size = region_page_size;
+
+ pds_vfio_print_guest_region_info(pds_vfio, max_regions);
+
+ return 0;
+
+err_free_bitmaps:
+ pds_vfio_dirty_free_bitmaps(dirty);
+err_out:
+ pds_vfio_dirty_set_disabled(pds_vfio);
+ return err;
+}
+
+static int
+pds_vfio_dirty_disable(struct pds_vfio_pci_device *pds_vfio)
+{
+ int err;
+
+ if (!pds_vfio_dirty_is_enabled(pds_vfio))
+ return 0;
+
+ pds_vfio_dirty_set_disabled(pds_vfio);
+ err = pds_vfio_dirty_disable_cmd(pds_vfio);
+ pds_vfio_dirty_free_sgl(pds_vfio);
+ pds_vfio_dirty_free_bitmaps(&pds_vfio->dirty);
+
+ return err;
+}
+
+static int
+pds_vfio_dirty_seq_ack(struct pds_vfio_pci_device *pds_vfio,
+ struct pds_vfio_bmp_info *bmp_info,
+ u32 offset, u32 bmp_bytes,
+ bool read_seq)
+{
+ const char *bmp_type_str = read_seq ? "read_seq" : "write_ack";
+ struct pci_dev *pdev = pds_vfio->pdev;
+ int bytes_remaining;
+ dma_addr_t bmp_dma;
+ u8 dma_direction;
+ u16 num_sge = 0;
+ int err, i;
+ u64 *bmp;
+
+ bmp = (u64 *)((u64)bmp_info->bmp + offset);
+
+ dma_direction = read_seq ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+ bmp_dma = dma_map_single(pds_vfio->coredev, bmp, bmp_bytes,
+ dma_direction);
+ if (dma_mapping_error(pds_vfio->coredev, bmp_dma))
+ return -EINVAL;
+
+ bytes_remaining = bmp_bytes;
+
+ for (i = 0; i < bmp_info->num_sge && bytes_remaining > 0; i++) {
+ struct pds_lm_sg_elem *sg_elem = &bmp_info->sgl[i];
+ u32 len = (bytes_remaining > PAGE_SIZE) ?
+ PAGE_SIZE : bytes_remaining;
+
+ sg_elem->addr = cpu_to_le64(bmp_dma + i * PAGE_SIZE);
+ sg_elem->len = cpu_to_le32(len);
+
+ bytes_remaining -= len;
+ ++num_sge;
+ }
+
+ err = pds_vfio_dirty_seq_ack_cmd(pds_vfio, bmp_info->sgl_addr,
+ num_sge, offset, bmp_bytes, read_seq);
+ if (err)
+ dev_err(&pdev->dev, "Dirty bitmap %s failed offset %u bmp_bytes %u num_sge %u DMA 0x%llx: %pe\n",
+ bmp_type_str, offset, bmp_bytes, num_sge, bmp_info->sgl_addr, ERR_PTR(err));
+
+ dma_unmap_single(pds_vfio->coredev, bmp_dma, bmp_bytes, dma_direction);
+
+ return err;
+}
+
+static int
+pds_vfio_dirty_write_ack(struct pds_vfio_pci_device *pds_vfio, u32 offset,
+ u32 len)
+{
+ return pds_vfio_dirty_seq_ack(pds_vfio,
+ &pds_vfio->dirty.host_ack, offset,
+ len, WRITE_ACK);
+}
+
+static int
+pds_vfio_dirty_read_seq(struct pds_vfio_pci_device *pds_vfio, u32 offset,
+ u32 len)
+{
+ return pds_vfio_dirty_seq_ack(pds_vfio,
+ &pds_vfio->dirty.host_seq, offset,
+ len, READ_SEQ);
+}
+
+static int
+pds_vfio_dirty_process_bitmaps(struct pds_vfio_pci_device *pds_vfio,
+ struct iova_bitmap *dirty_bitmap, u32 bmp_offset,
+ u32 len_bytes)
+{
+ u64 page_size = pds_vfio->dirty.region_page_size;
+ u64 region_start = pds_vfio->dirty.region_start;
+ u32 bmp_offset_bit;
+ int dword_count, i;
+ __le64 *seq, *ack;
+
+ dword_count = len_bytes / sizeof(u64);
+ seq = (__le64 *)((u64)pds_vfio->dirty.host_seq.bmp + bmp_offset);
+ ack = (__le64 *)((u64)pds_vfio->dirty.host_ack.bmp + bmp_offset);
+ bmp_offset_bit = bmp_offset * 8;
+
+ for (i = 0; i < dword_count; i++) {
+ u64 xor = le64_to_cpu(seq[i]) ^ le64_to_cpu(ack[i]);
+ u8 bit_i;
+
+ /* prepare for next write_ack call */
+ ack[i] = seq[i];
+
+#define BITS_PER_U64 (sizeof(u64) * BITS_PER_BYTE)
+ for (bit_i = 0; bit_i < BITS_PER_U64; ++bit_i) {
+ if (xor & BIT(bit_i)) {
+ u64 abs_bit_i = bmp_offset_bit + i *
+ BITS_PER_U64 + bit_i;
+ u64 addr = abs_bit_i * page_size + region_start;
+
+ iova_bitmap_set(dirty_bitmap, addr, page_size);
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int
+pds_vfio_dirty_sync(struct pds_vfio_pci_device *pds_vfio,
+ struct iova_bitmap *dirty_bitmap,
+ unsigned long iova, unsigned long length)
+{
+ struct pds_vfio_dirty *dirty = &pds_vfio->dirty;
+ struct pci_dev *pdev = pds_vfio->pdev;
+ u64 bmp_offset, bmp_bytes;
+ u64 bitmap_size, pages;
+ int err;
+
+ dev_dbg(&pdev->dev, "vf%u: Get dirty page bitmap\n", pds_vfio->vf_id);
+
+ if (!pds_vfio_dirty_is_enabled(pds_vfio)) {
+ dev_err(&pdev->dev, "vf%u: Sync failed, dirty tracking is disabled\n",
+ pds_vfio->vf_id);
+ return -EINVAL;
+ }
+
+ pages = DIV_ROUND_UP(length, pds_vfio->dirty.region_page_size);
+ bitmap_size = round_up(pages, sizeof(u64) * BITS_PER_BYTE) /
+ BITS_PER_BYTE;
+
+ dev_dbg(&pdev->dev, "vf%u: iova 0x%lx length %lu page_size %llu pages %llu bitmap_size %llu\n",
+ pds_vfio->vf_id, iova, length,
+ pds_vfio->dirty.region_page_size, pages, bitmap_size);
+
+ if (!length ||
+ ((dirty->region_start + iova + length) >
+ (dirty->region_start + dirty->region_size))) {
+ dev_err(&pdev->dev, "Invalid iova 0x%lx and/or length 0x%lx to sync\n",
+ iova, length);
+ return -EINVAL;
+ }
+
+ /* bitmap is modified in 64 bit chunks */
+ bmp_bytes = ALIGN(DIV_ROUND_UP(length / dirty->region_page_size,
+ sizeof(u64)), sizeof(u64));
+ if (bmp_bytes != bitmap_size) {
+ dev_err(&pdev->dev, "Calculated bitmap bytes %llu not equal to bitmap size %llu\n",
+ bmp_bytes, bitmap_size);
+ return -EINVAL;
+ }
+
+ bmp_offset = DIV_ROUND_UP(iova / dirty->region_page_size, sizeof(u64));
+
+ dev_dbg(&pdev->dev, "Syncing dirty bitmap, iova 0x%lx length 0x%lx, bmp_offset %llu bmp_bytes %llu\n",
+ iova, length, bmp_offset, bmp_bytes);
+
+ err = pds_vfio_dirty_read_seq(pds_vfio, bmp_offset, bmp_bytes);
+ if (err)
+ return err;
+
+ err = pds_vfio_dirty_process_bitmaps(pds_vfio, dirty_bitmap,
+ bmp_offset, bmp_bytes);
+ if (err)
+ return err;
+
+ err = pds_vfio_dirty_write_ack(pds_vfio, bmp_offset, bmp_bytes);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+int
+pds_vfio_dma_logging_report(struct vfio_device *vdev, unsigned long iova,
+ unsigned long length,
+ struct iova_bitmap *dirty)
+{
+ struct pds_vfio_pci_device *pds_vfio =
+ container_of(vdev, struct pds_vfio_pci_device,
+ vfio_coredev.vdev);
+
+ return pds_vfio_dirty_sync(pds_vfio, dirty, iova, length);
+}
+
+int
+pds_vfio_dma_logging_start(struct vfio_device *vdev,
+ struct rb_root_cached *ranges, u32 nnodes,
+ u64 *page_size)
+{
+ struct pds_vfio_pci_device *pds_vfio =
+ container_of(vdev, struct pds_vfio_pci_device,
+ vfio_coredev.vdev);
+ int err;
+
+ pds_vfio_send_host_vf_lm_status_cmd(pds_vfio, PDS_LM_STA_IN_PROGRESS);
+
+ err = pds_vfio_dirty_enable(pds_vfio, ranges, nnodes, page_size);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+int
+pds_vfio_dma_logging_stop(struct vfio_device *vdev)
+{
+ struct pds_vfio_pci_device *pds_vfio =
+ container_of(vdev, struct pds_vfio_pci_device,
+ vfio_coredev.vdev);
+
+ return pds_vfio_dirty_disable(pds_vfio);
+}
diff --git a/drivers/vfio/pci/pds/dirty.h b/drivers/vfio/pci/pds/dirty.h
new file mode 100644
index 000000000000..934b8600dfc1
--- /dev/null
+++ b/drivers/vfio/pci/pds/dirty.h
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2022 Pensando Systems, Inc */
+
+#ifndef _DIRTY_H_
+#define _DIRTY_H_
+
+#include <linux/types.h>
+#include <linux/iova_bitmap.h>
+
+#include <linux/pds/pds_lm.h>
+
+struct pds_vfio_bmp_info {
+ unsigned long *bmp;
+ u32 bmp_bytes;
+ struct pds_lm_sg_elem *sgl;
+ dma_addr_t sgl_addr;
+ u16 num_sge;
+};
+
+struct pds_vfio_dirty {
+ struct pds_vfio_bmp_info host_seq;
+ struct pds_vfio_bmp_info host_ack;
+ u64 region_size;
+ u64 region_start;
+ u64 region_page_size;
+ bool is_enabled;
+};
+
+struct pds_vfio_pci_device;
+
+bool
+pds_vfio_dirty_is_enabled(struct pds_vfio_pci_device *pds_vfio);
+void
+pds_vfio_dirty_set_enabled(struct pds_vfio_pci_device *pds_vfio);
+void
+pds_vfio_dirty_set_disabled(struct pds_vfio_pci_device *pds_vfio);
+
+int
+pds_vfio_dma_logging_report(struct vfio_device *vdev, unsigned long iova,
+ unsigned long length,
+ struct iova_bitmap *dirty);
+int
+pds_vfio_dma_logging_start(struct vfio_device *vdev,
+ struct rb_root_cached *ranges, u32 nnodes,
+ u64 *page_size);
+int
+pds_vfio_dma_logging_stop(struct vfio_device *vdev);
+#endif /* _DIRTY_H_ */
diff --git a/drivers/vfio/pci/pds/lm.h b/drivers/vfio/pci/pds/lm.h
index 3dd97b807db6..882342c571fc 100644
--- a/drivers/vfio/pci/pds/lm.h
+++ b/drivers/vfio/pci/pds/lm.h
@@ -33,6 +33,16 @@ struct pds_vfio_pci_device;
struct file *
pds_vfio_step_device_state_locked(struct pds_vfio_pci_device *pds_vfio,
enum vfio_device_mig_state next);
+int
+pds_vfio_dma_logging_report(struct vfio_device *vdev, unsigned long iova,
+ unsigned long length,
+ struct iova_bitmap *dirty);
+int
+pds_vfio_dma_logging_start(struct vfio_device *vdev,
+ struct rb_root_cached *ranges, u32 nnodes,
+ u64 *page_size);
+int
+pds_vfio_dma_logging_stop(struct vfio_device *vdev);
const char *
pds_vfio_lm_state(enum vfio_device_mig_state state);
void
diff --git a/drivers/vfio/pci/pds/vfio_dev.c b/drivers/vfio/pci/pds/vfio_dev.c
index d28f96f93097..67fe62ad98c9 100644
--- a/drivers/vfio/pci/pds/vfio_dev.c
+++ b/drivers/vfio/pci/pds/vfio_dev.c
@@ -5,6 +5,7 @@
#include <linux/vfio_pci_core.h>

#include "lm.h"
+#include "dirty.h"
#include "vfio_dev.h"
#include "aux_drv.h"

@@ -108,6 +109,13 @@ pds_vfio_lm_ops = {
.migration_get_state = pds_vfio_get_device_state
};

+static const struct vfio_log_ops
+pds_vfio_log_ops = {
+ .log_start = pds_vfio_dma_logging_start,
+ .log_stop = pds_vfio_dma_logging_stop,
+ .log_read_and_clear = pds_vfio_dma_logging_report,
+};
+
static int
pds_vfio_init_device(struct vfio_device *vdev)
{
@@ -134,6 +142,7 @@ pds_vfio_init_device(struct vfio_device *vdev)

vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P;
vdev->mig_ops = &pds_vfio_lm_ops;
+ vdev->log_ops = &pds_vfio_log_ops;

dev_dbg(&pdev->dev, "%s: PF %#04x VF %#04x (%d) vf_id %d domain %d vfio_aux %p pds_vfio %p\n",
__func__, pci_dev_id(pdev->physfn),
diff --git a/drivers/vfio/pci/pds/vfio_dev.h b/drivers/vfio/pci/pds/vfio_dev.h
index a09570eec6fa..42bfea448c10 100644
--- a/drivers/vfio/pci/pds/vfio_dev.h
+++ b/drivers/vfio/pci/pds/vfio_dev.h
@@ -7,6 +7,7 @@
#include <linux/pci.h>
#include <linux/vfio_pci_core.h>

+#include "dirty.h"
#include "lm.h"

struct pds_vfio_pci_device {
@@ -17,6 +18,7 @@ struct pds_vfio_pci_device {

struct pds_vfio_lm_file *save_file;
struct pds_vfio_lm_file *restore_file;
+ struct pds_vfio_dirty dirty;
struct mutex state_mutex; /* protect migration state */
enum vfio_device_mig_state state;
spinlock_t reset_lock; /* protect reset_done flow */
diff --git a/include/linux/pds/pds_lm.h b/include/linux/pds/pds_lm.h
index 28ebd62f7583..c7e83932f2fb 100644
--- a/include/linux/pds/pds_lm.h
+++ b/include/linux/pds/pds_lm.h
@@ -25,6 +25,13 @@ enum pds_lm_cmd_opcode {
PDS_LM_CMD_RESUME = 20,
PDS_LM_CMD_SAVE = 21,
PDS_LM_CMD_RESTORE = 22,
+
+ /* Dirty page tracking commands */
+ PDS_LM_CMD_DIRTY_STATUS = 32,
+ PDS_LM_CMD_DIRTY_ENABLE = 33,
+ PDS_LM_CMD_DIRTY_DISABLE = 34,
+ PDS_LM_CMD_DIRTY_READ_SEQ = 35,
+ PDS_LM_CMD_DIRTY_WRITE_ACK = 36,
};

/**
@@ -215,4 +222,170 @@ struct pds_lm_host_vf_status_cmd {
u8 status;
};

+/**
+ * struct pds_lm_dirty_region_info - Memory region info for STATUS and ENABLE
+ * @dma_base: Base address of the DMA-contiguous memory region
+ * @page_count: Number of pages in the memory region
+ * @page_size_log2: Log2 page size in the memory region
+ * @rsvd: Word boundary padding
+ */
+struct pds_lm_dirty_region_info {
+ __le64 dma_base;
+ __le32 page_count;
+ u8 page_size_log2;
+ u8 rsvd[3];
+};
+
+/**
+ * struct pds_lm_dirty_status_cmd - DIRTY_STATUS command
+ * @opcode: Opcode PDS_LM_CMD_DIRTY_STATUS
+ * @rsvd: Word boundary padding
+ * @vf_id: VF id
+ * @max_regions: Capacity of the region info buffer
+ * @rsvd2: Word boundary padding
+ * @regions_dma: DMA address of the region info buffer
+ *
+ * The minimum of max_regions (from the command) and num_regions (from the
+ * completion) of struct pds_lm_dirty_region_info will be written to
+ * regions_dma.
+ *
+ * The max_regions may be zero, in which case regions_dma is ignored. In that
+ * case, the completion will only report the maximum number of regions
+ * supported by the device, and the number of regions currently enabled.
+ */
+struct pds_lm_dirty_status_cmd {
+ u8 opcode;
+ u8 rsvd;
+ __le16 vf_id;
+ u8 max_regions;
+ u8 rsvd2[3];
+ __le64 regions_dma;
+} __packed;
+
+/**
+ * enum pds_lm_dirty_bmp_type - Type of dirty page bitmap
+ * @PDS_LM_DIRTY_BMP_TYPE_NONE: No bitmap / disabled
+ * @PDS_LM_DIRTY_BMP_TYPE_SEQ_ACK: Seq/Ack bitmap representation
+ */
+enum pds_lm_dirty_bmp_type {
+ PDS_LM_DIRTY_BMP_TYPE_NONE = 0,
+ PDS_LM_DIRTY_BMP_TYPE_SEQ_ACK = 1,
+};
+
+/**
+ * struct pds_lm_dirty_status_comp - STATUS command completion
+ * @status: Status of the command (enum pds_core_status_code)
+ * @rsvd: Word boundary padding
+ * @comp_index: Index in the desc ring for which this is the completion
+ * @max_regions: Maximum number of regions supported by the device
+ * @num_regions: Number of regions currently enabled
+ * @bmp_type: Type of dirty bitmap representation
+ * @rsvd2: Word boundary padding
+ * @bmp_type_mask: Mask of supported bitmap types, bit index per type
+ * @rsvd3: Word boundary padding
+ * @color: Color bit
+ *
+ * This completion descriptor is used for STATUS, ENABLE, and DISABLE.
+ */
+struct pds_lm_dirty_status_comp {
+ u8 status;
+ u8 rsvd;
+ __le16 comp_index;
+ u8 max_regions;
+ u8 num_regions;
+ u8 bmp_type;
+ u8 rsvd2;
+ __le32 bmp_type_mask;
+ u8 rsvd3[3];
+ u8 color;
+};
+
+/**
+ * struct pds_lm_dirty_enable_cmd - DIRTY_ENABLE command
+ * @opcode: Opcode PDS_LM_CMD_DIRTY_ENABLE
+ * @rsvd: Word boundary padding
+ * @vf_id: VF id
+ * @bmp_type: Type of dirty bitmap representation
+ * @num_regions: Number of entries in the region info buffer
+ * @rsvd2: Word boundary padding
+ * @regions_dma: DMA address of the region info buffer
+ *
+ * The num_regions must be nonzero, and less than or equal to the maximum
+ * number of regions supported by the device.
+ *
+ * The memory regions should not overlap.
+ *
+ * The information should be initialized by the driver. The device may modify
+ * the information on successful completion, such as by size-aligning the
+ * number of pages in a region.
+ *
+ * The modified number of pages will be greater than or equal to the page count
+ * given in the enable command, and at least as coarsly aligned as the given
+ * value. For example, the count might be aligned to a multiple of 64, but
+ * if the value is already a multiple of 128 or higher, it will not change.
+ * If the driver requires its own minimum alignment of the number of pages, the
+ * driver should account for that already in the region info of this command.
+ *
+ * This command uses struct pds_lm_dirty_status_comp for its completion.
+ */
+struct pds_lm_dirty_enable_cmd {
+ u8 opcode;
+ u8 rsvd;
+ __le16 vf_id;
+ u8 bmp_type;
+ u8 num_regions;
+ u8 rsvd2[2];
+ __le64 regions_dma;
+} __packed;
+
+/**
+ * struct pds_lm_dirty_disable_cmd - DIRTY_DISABLE command
+ * @opcode: Opcode PDS_LM_CMD_DIRTY_DISABLE
+ * @rsvd: Word boundary padding
+ * @vf_id: VF id
+ *
+ * Dirty page tracking will be disabled. This may be called in any state, as
+ * long as dirty page tracking is supported by the device, to ensure that dirty
+ * page tracking is disabled.
+ *
+ * This command uses struct pds_lm_dirty_status_comp for its completion. On
+ * success, num_regions will be zero.
+ */
+struct pds_lm_dirty_disable_cmd {
+ u8 opcode;
+ u8 rsvd;
+ __le16 vf_id;
+};
+
+/**
+ * struct pds_lm_dirty_seq_ack_cmd - DIRTY_READ_SEQ or _WRITE_ACK command
+ * @opcode: Opcode PDS_LM_CMD_DIRTY_[READ_SEQ|WRITE_ACK]
+ * @rsvd: Word boundary padding
+ * @vf_id: VF id
+ * @off_bytes: Byte offset in the bitmap
+ * @len_bytes: Number of bytes to transfer
+ * @num_sge: Number of DMA scatter gather elements
+ * @rsvd2: Word boundary padding
+ * @sgl_addr: DMA address of scatter gather list
+ *
+ * Read bytes from the SEQ bitmap, or write bytes into the ACK bitmap.
+ *
+ * This command treats the entire bitmap as a byte buffer. It does not
+ * distinguish between guest memory regions. The driver should refer to the
+ * number of pages in each region, according to PDS_LM_CMD_DIRTY_STATUS, to
+ * determine the region boundaries in the bitmap. Each region will be
+ * represented by exactly the number of bits as the page count for that region,
+ * immediately following the last bit of the previous region.
+ */
+struct pds_lm_dirty_seq_ack_cmd {
+ u8 opcode;
+ u8 rsvd;
+ __le16 vf_id;
+ __le32 off_bytes;
+ __le32 len_bytes;
+ __le16 num_sge;
+ u8 rsvd2[2];
+ __le64 sgl_addr;
+} __packed;
+
#endif /* _PDS_LM_H_ */
--
2.17.1