vfio/pds: Add VFIO live migration support

Add live migration support via the VFIO subsystem. The migration
implementation aligns with the definition from uapi/vfio.h and uses
the pds_core PF's adminq for device configuration.

The ability to suspend, resume, and transfer VF device state data is
included along with the required admin queue command structures and
implementations.

PDS_LM_CMD_SUSPEND and PDS_LM_CMD_SUSPEND_STATUS are added to support
the VF device suspend operation.

PDS_LM_CMD_RESUME is added to support the VF device resume operation.

PDS_LM_CMD_STATE_SIZE is added to determine the exact size of the VF
device state data.

PDS_LM_CMD_SAVE is added to get the VF device state data.

PDS_LM_CMD_RESTORE is added to restore the VF device with the
previously saved data from PDS_LM_CMD_SAVE.

PDS_LM_CMD_HOST_VF_STATUS is added to notify the DSC/firmware when
a migration is in/not-in progress from the host's perspective. The
DSC/firmware can use this to clear/setup any necessary state related
to a migration.

Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230807205755.29579-6-brett.creeley@amd.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

8 files changed, 956 insertions, 2 deletions

diff --git a/drivers/vfio/pci/pds/Makefile b/drivers/vfio/pci/pds/Makefile
index 91587c7fe8f9..47750bb31ea2 100644
--- a/drivers/vfio/pci/pds/Makefile
+++ b/drivers/vfio/pci/pds/Makefile
@@ -5,5 +5,6 @@ obj-$(CONFIG_PDS_VFIO_PCI) += pds-vfio-pci.o
 
 pds-vfio-pci-y := \
 	cmds.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 7f1618aa765d..b1c5f103500f 100644
--- a/drivers/vfio/pci/pds/cmds.c
+++ b/drivers/vfio/pci/pds/cmds.c
@@ -3,6 +3,7 @@
 
 #include <linux/io.h>
 #include <linux/types.h>
+#include <linux/delay.h>
 
 #include <linux/pds/pds_common.h>
 #include <linux/pds/pds_core_if.h>
@@ -11,6 +12,37 @@
 #include "vfio_dev.h"
 #include "cmds.h"
 
+#define SUSPEND_TIMEOUT_S		5
+#define SUSPEND_CHECK_INTERVAL_MS	1
+
+static int pds_vfio_client_adminq_cmd(struct pds_vfio_pci_device *pds_vfio,
+				      union pds_core_adminq_cmd *req,
+				      union pds_core_adminq_comp *resp,
+				      bool fast_poll)
+{
+	struct pci_dev *pdev = pds_vfio_to_pci_dev(pds_vfio);
+	union pds_core_adminq_cmd cmd = {};
+	struct pdsc *pdsc;
+	int err;
+
+	/* Wrap the client request */
+	cmd.client_request.opcode = PDS_AQ_CMD_CLIENT_CMD;
+	cmd.client_request.client_id = cpu_to_le16(pds_vfio->client_id);
+	memcpy(cmd.client_request.client_cmd, req,
+	       sizeof(cmd.client_request.client_cmd));
+
+	pdsc = pdsc_get_pf_struct(pdev);
+	if (IS_ERR(pdsc))
+		return PTR_ERR(pdsc);
+
+	err = pdsc_adminq_post(pdsc, &cmd, resp, fast_poll);
+	if (err && err != -EAGAIN)
+		dev_err(pds_vfio_to_dev(pds_vfio),
+			"client admin cmd failed: %pe\n", ERR_PTR(err));
+
+	return err;
+}
+
 int pds_vfio_register_client_cmd(struct pds_vfio_pci_device *pds_vfio)
 {
 	struct pci_dev *pdev = pds_vfio_to_pci_dev(pds_vfio);
@@ -52,3 +84,301 @@ void pds_vfio_unregister_client_cmd(struct pds_vfio_pci_device *pds_vfio)
 
 	pds_vfio->client_id = 0;
 }
+
+static int
+pds_vfio_suspend_wait_device_cmd(struct pds_vfio_pci_device *pds_vfio)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_suspend_status = {
+			.opcode = PDS_LM_CMD_SUSPEND_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 = {};
+	unsigned long time_limit;
+	unsigned long time_start;
+	unsigned long time_done;
+	int err;
+
+	time_start = jiffies;
+	time_limit = time_start + HZ * SUSPEND_TIMEOUT_S;
+	do {
+		err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, true);
+		if (err != -EAGAIN)
+			break;
+
+		msleep(SUSPEND_CHECK_INTERVAL_MS);
+	} while (time_before(jiffies, time_limit));
+
+	time_done = jiffies;
+	dev_dbg(dev, "%s: vf%u: Suspend comp received in %d msecs\n", __func__,
+		pds_vfio->vf_id, jiffies_to_msecs(time_done - time_start));
+
+	/* Check the results */
+	if (time_after_eq(time_done, time_limit)) {
+		dev_err(dev, "%s: vf%u: Suspend comp timeout\n", __func__,
+			pds_vfio->vf_id);
+		err = -ETIMEDOUT;
+	}
+
+	return err;
+}
+
+int pds_vfio_suspend_device_cmd(struct pds_vfio_pci_device *pds_vfio, u8 type)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_suspend = {
+			.opcode = PDS_LM_CMD_SUSPEND,
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+			.type = type,
+		},
+	};
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	union pds_core_adminq_comp comp = {};
+	int err;
+
+	dev_dbg(dev, "vf%u: Suspend device\n", pds_vfio->vf_id);
+
+	/*
+	 * The initial suspend request to the firmware starts the device suspend
+	 * operation and the firmware returns success if it's started
+	 * successfully.
+	 */
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, true);
+	if (err) {
+		dev_err(dev, "vf%u: Suspend failed: %pe\n", pds_vfio->vf_id,
+			ERR_PTR(err));
+		return err;
+	}
+
+	/*
+	 * The subsequent suspend status request(s) check if the firmware has
+	 * completed the device suspend process.
+	 */
+	return pds_vfio_suspend_wait_device_cmd(pds_vfio);
+}
+
+int pds_vfio_resume_device_cmd(struct pds_vfio_pci_device *pds_vfio, u8 type)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_resume = {
+			.opcode = PDS_LM_CMD_RESUME,
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+			.type = type,
+		},
+	};
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	union pds_core_adminq_comp comp = {};
+
+	dev_dbg(dev, "vf%u: Resume device\n", pds_vfio->vf_id);
+
+	return pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, true);
+}
+
+int pds_vfio_get_lm_state_size_cmd(struct pds_vfio_pci_device *pds_vfio, u64 *size)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_state_size = {
+			.opcode = PDS_LM_CMD_STATE_SIZE,
+			.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: Get migration status\n", pds_vfio->vf_id);
+
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, false);
+	if (err)
+		return err;
+
+	*size = le64_to_cpu(comp.lm_state_size.size);
+	return 0;
+}
+
+static int pds_vfio_dma_map_lm_file(struct device *dev,
+				    enum dma_data_direction dir,
+				    struct pds_vfio_lm_file *lm_file)
+{
+	struct pds_lm_sg_elem *sgl, *sge;
+	struct scatterlist *sg;
+	dma_addr_t sgl_addr;
+	size_t sgl_size;
+	int err;
+	int i;
+
+	if (!lm_file)
+		return -EINVAL;
+
+	/* dma map file pages */
+	err = dma_map_sgtable(dev, &lm_file->sg_table, dir, 0);
+	if (err)
+		return err;
+
+	lm_file->num_sge = lm_file->sg_table.nents;
+
+	/* alloc sgl */
+	sgl_size = lm_file->num_sge * sizeof(struct pds_lm_sg_elem);
+	sgl = kzalloc(sgl_size, GFP_KERNEL);
+	if (!sgl) {
+		err = -ENOMEM;
+		goto out_unmap_sgtable;
+	}
+
+	/* fill sgl */
+	sge = sgl;
+	for_each_sgtable_dma_sg(&lm_file->sg_table, sg, i) {
+		sge->addr = cpu_to_le64(sg_dma_address(sg));
+		sge->len = cpu_to_le32(sg_dma_len(sg));
+		dev_dbg(dev, "addr = %llx, len = %u\n", sge->addr, sge->len);
+		sge++;
+	}
+
+	sgl_addr = dma_map_single(dev, sgl, sgl_size, DMA_TO_DEVICE);
+	if (dma_mapping_error(dev, sgl_addr)) {
+		err = -EIO;
+		goto out_free_sgl;
+	}
+
+	lm_file->sgl = sgl;
+	lm_file->sgl_addr = sgl_addr;
+
+	return 0;
+
+out_free_sgl:
+	kfree(sgl);
+out_unmap_sgtable:
+	lm_file->num_sge = 0;
+	dma_unmap_sgtable(dev, &lm_file->sg_table, dir, 0);
+	return err;
+}
+
+static void pds_vfio_dma_unmap_lm_file(struct device *dev,
+				       enum dma_data_direction dir,
+				       struct pds_vfio_lm_file *lm_file)
+{
+	if (!lm_file)
+		return;
+
+	/* free sgl */
+	if (lm_file->sgl) {
+		dma_unmap_single(dev, lm_file->sgl_addr,
+				 lm_file->num_sge * sizeof(*lm_file->sgl),
+				 DMA_TO_DEVICE);
+		kfree(lm_file->sgl);
+		lm_file->sgl = NULL;
+		lm_file->sgl_addr = DMA_MAPPING_ERROR;
+		lm_file->num_sge = 0;
+	}
+
+	/* dma unmap file pages */
+	dma_unmap_sgtable(dev, &lm_file->sg_table, dir, 0);
+}
+
+int pds_vfio_get_lm_state_cmd(struct pds_vfio_pci_device *pds_vfio)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_save = {
+			.opcode = PDS_LM_CMD_SAVE,
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+		},
+	};
+	struct pci_dev *pdev = pds_vfio_to_pci_dev(pds_vfio);
+	struct device *pdsc_dev = &pci_physfn(pdev)->dev;
+	union pds_core_adminq_comp comp = {};
+	struct pds_vfio_lm_file *lm_file;
+	int err;
+
+	dev_dbg(&pdev->dev, "vf%u: Get migration state\n", pds_vfio->vf_id);
+
+	lm_file = pds_vfio->save_file;
+
+	err = pds_vfio_dma_map_lm_file(pdsc_dev, DMA_FROM_DEVICE, lm_file);
+	if (err) {
+		dev_err(&pdev->dev, "failed to map save migration file: %pe\n",
+			ERR_PTR(err));
+		return err;
+	}
+
+	cmd.lm_save.sgl_addr = cpu_to_le64(lm_file->sgl_addr);
+	cmd.lm_save.num_sge = cpu_to_le32(lm_file->num_sge);
+
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, false);
+	if (err)
+		dev_err(&pdev->dev, "failed to get migration state: %pe\n",
+			ERR_PTR(err));
+
+	pds_vfio_dma_unmap_lm_file(pdsc_dev, DMA_FROM_DEVICE, lm_file);
+
+	return err;
+}
+
+int pds_vfio_set_lm_state_cmd(struct pds_vfio_pci_device *pds_vfio)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_restore = {
+			.opcode = PDS_LM_CMD_RESTORE,
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+		},
+	};
+	struct pci_dev *pdev = pds_vfio_to_pci_dev(pds_vfio);
+	struct device *pdsc_dev = &pci_physfn(pdev)->dev;
+	union pds_core_adminq_comp comp = {};
+	struct pds_vfio_lm_file *lm_file;
+	int err;
+
+	dev_dbg(&pdev->dev, "vf%u: Set migration state\n", pds_vfio->vf_id);
+
+	lm_file = pds_vfio->restore_file;
+
+	err = pds_vfio_dma_map_lm_file(pdsc_dev, DMA_TO_DEVICE, lm_file);
+	if (err) {
+		dev_err(&pdev->dev,
+			"failed to map restore migration file: %pe\n",
+			ERR_PTR(err));
+		return err;
+	}
+
+	cmd.lm_restore.sgl_addr = cpu_to_le64(lm_file->sgl_addr);
+	cmd.lm_restore.num_sge = cpu_to_le32(lm_file->num_sge);
+
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, false);
+	if (err)
+		dev_err(&pdev->dev, "failed to set migration state: %pe\n",
+			ERR_PTR(err));
+
+	pds_vfio_dma_unmap_lm_file(pdsc_dev, DMA_TO_DEVICE, lm_file);
+
+	return err;
+}
+
+void pds_vfio_send_host_vf_lm_status_cmd(struct pds_vfio_pci_device *pds_vfio,
+					 enum pds_lm_host_vf_status vf_status)
+{
+	union pds_core_adminq_cmd cmd = {
+		.lm_host_vf_status = {
+			.opcode = PDS_LM_CMD_HOST_VF_STATUS,
+			.vf_id = cpu_to_le16(pds_vfio->vf_id),
+			.status = vf_status,
+		},
+	};
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	union pds_core_adminq_comp comp = {};
+	int err;
+
+	dev_dbg(dev, "vf%u: Set host VF LM status: %u", pds_vfio->vf_id,
+		vf_status);
+	if (vf_status != PDS_LM_STA_IN_PROGRESS &&
+	    vf_status != PDS_LM_STA_NONE) {
+		dev_warn(dev, "Invalid host VF migration status, %d\n",
+			 vf_status);
+		return;
+	}
+
+	err = pds_vfio_client_adminq_cmd(pds_vfio, &cmd, &comp, false);
+	if (err)
+		dev_warn(dev, "failed to send host VF migration status: %pe\n",
+			 ERR_PTR(err));
+}
diff --git a/drivers/vfio/pci/pds/cmds.h b/drivers/vfio/pci/pds/cmds.h
index 4c592afccf89..a0ec169f18a1 100644
--- a/drivers/vfio/pci/pds/cmds.h
+++ b/drivers/vfio/pci/pds/cmds.h
@@ -6,5 +6,11 @@
 
 int pds_vfio_register_client_cmd(struct pds_vfio_pci_device *pds_vfio);
 void pds_vfio_unregister_client_cmd(struct pds_vfio_pci_device *pds_vfio);
-
+int pds_vfio_suspend_device_cmd(struct pds_vfio_pci_device *pds_vfio, u8 type);
+int pds_vfio_resume_device_cmd(struct pds_vfio_pci_device *pds_vfio, u8 type);
+int pds_vfio_get_lm_state_size_cmd(struct pds_vfio_pci_device *pds_vfio, u64 *size);
+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);
 #endif /* _CMDS_H_ */
diff --git a/drivers/vfio/pci/pds/lm.c b/drivers/vfio/pci/pds/lm.c
new file mode 100644
index 000000000000..7e319529cf74
--- /dev/null
+++ b/drivers/vfio/pci/pds/lm.c
@@ -0,0 +1,434 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2023 Advanced Micro Devices, Inc. */
+
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/highmem.h>
+#include <linux/vfio.h>
+#include <linux/vfio_pci_core.h>
+
+#include "vfio_dev.h"
+#include "cmds.h"
+
+static struct pds_vfio_lm_file *
+pds_vfio_get_lm_file(const struct file_operations *fops, int flags, u64 size)
+{
+	struct pds_vfio_lm_file *lm_file = NULL;
+	unsigned long long npages;
+	struct page **pages;
+	void *page_mem;
+	const void *p;
+
+	if (!size)
+		return NULL;
+
+	/* Alloc file structure */
+	lm_file = kzalloc(sizeof(*lm_file), GFP_KERNEL);
+	if (!lm_file)
+		return NULL;
+
+	/* Create file */
+	lm_file->filep =
+		anon_inode_getfile("pds_vfio_lm", fops, lm_file, flags);
+	if (!lm_file->filep)
+		goto out_free_file;
+
+	stream_open(lm_file->filep->f_inode, lm_file->filep);
+	mutex_init(&lm_file->lock);
+
+	/* prevent file from being released before we are done with it */
+	get_file(lm_file->filep);
+
+	/* Allocate memory for file pages */
+	npages = DIV_ROUND_UP_ULL(size, PAGE_SIZE);
+	pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL);
+	if (!pages)
+		goto out_put_file;
+
+	page_mem = kvzalloc(ALIGN(size, PAGE_SIZE), GFP_KERNEL);
+	if (!page_mem)
+		goto out_free_pages_array;
+
+	p = page_mem - offset_in_page(page_mem);
+	for (unsigned long long i = 0; i < npages; i++) {
+		if (is_vmalloc_addr(p))
+			pages[i] = vmalloc_to_page(p);
+		else
+			pages[i] = kmap_to_page((void *)p);
+		if (!pages[i])
+			goto out_free_page_mem;
+
+		p += PAGE_SIZE;
+	}
+
+	/* Create scatterlist of file pages to use for DMA mapping later */
+	if (sg_alloc_table_from_pages(&lm_file->sg_table, pages, npages, 0,
+				      size, GFP_KERNEL))
+		goto out_free_page_mem;
+
+	lm_file->size = size;
+	lm_file->pages = pages;
+	lm_file->npages = npages;
+	lm_file->page_mem = page_mem;
+	lm_file->alloc_size = npages * PAGE_SIZE;
+
+	return lm_file;
+
+out_free_page_mem:
+	kvfree(page_mem);
+out_free_pages_array:
+	kfree(pages);
+out_put_file:
+	fput(lm_file->filep);
+	mutex_destroy(&lm_file->lock);
+out_free_file:
+	kfree(lm_file);
+
+	return NULL;
+}
+
+static void pds_vfio_put_lm_file(struct pds_vfio_lm_file *lm_file)
+{
+	mutex_lock(&lm_file->lock);
+
+	lm_file->size = 0;
+	lm_file->alloc_size = 0;
+
+	/* Free scatter list of file pages */
+	sg_free_table(&lm_file->sg_table);
+
+	kvfree(lm_file->page_mem);
+	lm_file->page_mem = NULL;
+	kfree(lm_file->pages);
+	lm_file->pages = NULL;
+
+	mutex_unlock(&lm_file->lock);
+
+	/* allow file to be released since we are done with it */
+	fput(lm_file->filep);
+}
+
+void pds_vfio_put_save_file(struct pds_vfio_pci_device *pds_vfio)
+{
+	if (!pds_vfio->save_file)
+		return;
+
+	pds_vfio_put_lm_file(pds_vfio->save_file);
+	pds_vfio->save_file = NULL;
+}
+
+void pds_vfio_put_restore_file(struct pds_vfio_pci_device *pds_vfio)
+{
+	if (!pds_vfio->restore_file)
+		return;
+
+	pds_vfio_put_lm_file(pds_vfio->restore_file);
+	pds_vfio->restore_file = NULL;
+}
+
+static struct page *pds_vfio_get_file_page(struct pds_vfio_lm_file *lm_file,
+					   unsigned long offset)
+{
+	unsigned long cur_offset = 0;
+	struct scatterlist *sg;
+	unsigned int i;
+
+	/* All accesses are sequential */
+	if (offset < lm_file->last_offset || !lm_file->last_offset_sg) {
+		lm_file->last_offset = 0;
+		lm_file->last_offset_sg = lm_file->sg_table.sgl;
+		lm_file->sg_last_entry = 0;
+	}
+
+	cur_offset = lm_file->last_offset;
+
+	for_each_sg(lm_file->last_offset_sg, sg,
+		    lm_file->sg_table.orig_nents - lm_file->sg_last_entry, i) {
+		if (offset < sg->length + cur_offset) {
+			lm_file->last_offset_sg = sg;
+			lm_file->sg_last_entry += i;
+			lm_file->last_offset = cur_offset;
+			return nth_page(sg_page(sg),
+					(offset - cur_offset) / PAGE_SIZE);
+		}
+		cur_offset += sg->length;
+	}
+
+	return NULL;
+}
+
+static int pds_vfio_release_file(struct inode *inode, struct file *filp)
+{
+	struct pds_vfio_lm_file *lm_file = filp->private_data;
+
+	mutex_lock(&lm_file->lock);
+	lm_file->filep->f_pos = 0;
+	lm_file->size = 0;
+	mutex_unlock(&lm_file->lock);
+	mutex_destroy(&lm_file->lock);
+	kfree(lm_file);
+
+	return 0;
+}
+
+static ssize_t pds_vfio_save_read(struct file *filp, char __user *buf,
+				  size_t len, loff_t *pos)
+{
+	struct pds_vfio_lm_file *lm_file = filp->private_data;
+	ssize_t done = 0;
+
+	if (pos)
+		return -ESPIPE;
+	pos = &filp->f_pos;
+
+	mutex_lock(&lm_file->lock);
+	if (*pos > lm_file->size) {
+		done = -EINVAL;
+		goto out_unlock;
+	}
+
+	len = min_t(size_t, lm_file->size - *pos, len);
+	while (len) {
+		size_t page_offset;
+		struct page *page;
+		size_t page_len;
+		u8 *from_buff;
+		int err;
+
+		page_offset = (*pos) % PAGE_SIZE;
+		page = pds_vfio_get_file_page(lm_file, *pos - page_offset);
+		if (!page) {
+			if (done == 0)
+				done = -EINVAL;
+			goto out_unlock;
+		}
+
+		page_len = min_t(size_t, len, PAGE_SIZE - page_offset);
+		from_buff = kmap_local_page(page);
+		err = copy_to_user(buf, from_buff + page_offset, page_len);
+		kunmap_local(from_buff);
+		if (err) {
+			done = -EFAULT;
+			goto out_unlock;
+		}
+		*pos += page_len;
+		len -= page_len;
+		done += page_len;
+		buf += page_len;
+	}
+
+out_unlock:
+	mutex_unlock(&lm_file->lock);
+	return done;
+}
+
+static const struct file_operations pds_vfio_save_fops = {
+	.owner = THIS_MODULE,
+	.read = pds_vfio_save_read,
+	.release = pds_vfio_release_file,
+	.llseek = no_llseek,
+};
+
+static int pds_vfio_get_save_file(struct pds_vfio_pci_device *pds_vfio)
+{
+	struct device *dev = &pds_vfio->vfio_coredev.pdev->dev;
+	struct pds_vfio_lm_file *lm_file;
+	u64 size;
+	int err;
+
+	/* Get live migration state size in this state */
+	err = pds_vfio_get_lm_state_size_cmd(pds_vfio, &size);
+	if (err) {
+		dev_err(dev, "failed to get save status: %pe\n", ERR_PTR(err));
+		return err;
+	}
+
+	dev_dbg(dev, "save status, size = %lld\n", size);
+
+	if (!size) {
+		dev_err(dev, "invalid state size\n");
+		return -EIO;
+	}
+
+	lm_file = pds_vfio_get_lm_file(&pds_vfio_save_fops, O_RDONLY, size);
+	if (!lm_file) {
+		dev_err(dev, "failed to create save file\n");
+		return -ENOENT;
+	}
+
+	dev_dbg(dev, "size = %lld, alloc_size = %lld, npages = %lld\n",
+		lm_file->size, lm_file->alloc_size, lm_file->npages);
+
+	pds_vfio->save_file = lm_file;
+
+	return 0;
+}
+
+static ssize_t pds_vfio_restore_write(struct file *filp, const char __user *buf,
+				      size_t len, loff_t *pos)
+{
+	struct pds_vfio_lm_file *lm_file = filp->private_data;
+	loff_t requested_length;
+	ssize_t done = 0;
+
+	if (pos)
+		return -ESPIPE;
+
+	pos = &filp->f_pos;
+
+	if (*pos < 0 ||
+	    check_add_overflow((loff_t)len, *pos, &requested_length))
+		return -EINVAL;
+
+	mutex_lock(&lm_file->lock);
+
+	while (len) {
+		size_t page_offset;
+		struct page *page;
+		size_t page_len;
+		u8 *to_buff;
+		int err;
+
+		page_offset = (*pos) % PAGE_SIZE;
+		page = pds_vfio_get_file_page(lm_file, *pos - page_offset);
+		if (!page) {
+			if (done == 0)
+				done = -EINVAL;
+			goto out_unlock;
+		}
+
+		page_len = min_t(size_t, len, PAGE_SIZE - page_offset);
+		to_buff = kmap_local_page(page);
+		err = copy_from_user(to_buff + page_offset, buf, page_len);
+		kunmap_local(to_buff);
+		if (err) {
+			done = -EFAULT;
+			goto out_unlock;
+		}
+		*pos += page_len;
+		len -= page_len;
+		done += page_len;
+		buf += page_len;
+		lm_file->size += page_len;
+	}
+out_unlock:
+	mutex_unlock(&lm_file->lock);
+	return done;
+}
+
+static const struct file_operations pds_vfio_restore_fops = {
+	.owner = THIS_MODULE,
+	.write = pds_vfio_restore_write,
+	.release = pds_vfio_release_file,
+	.llseek = no_llseek,
+};
+
+static int pds_vfio_get_restore_file(struct pds_vfio_pci_device *pds_vfio)
+{
+	struct device *dev = &pds_vfio->vfio_coredev.pdev->dev;
+	struct pds_vfio_lm_file *lm_file;
+	u64 size;
+
+	size = sizeof(union pds_lm_dev_state);
+	dev_dbg(dev, "restore status, size = %lld\n", size);
+
+	if (!size) {
+		dev_err(dev, "invalid state size");
+		return -EIO;
+	}
+
+	lm_file = pds_vfio_get_lm_file(&pds_vfio_restore_fops, O_WRONLY, size);
+	if (!lm_file) {
+		dev_err(dev, "failed to create restore file");
+		return -ENOENT;
+	}
+	pds_vfio->restore_file = lm_file;
+
+	return 0;
+}
+
+struct file *
+pds_vfio_step_device_state_locked(struct pds_vfio_pci_device *pds_vfio,
+				  enum vfio_device_mig_state next)
+{
+	enum vfio_device_mig_state cur = pds_vfio->state;
+	int err;
+
+	if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_STOP_COPY) {
+		err = pds_vfio_get_save_file(pds_vfio);
+		if (err)
+			return ERR_PTR(err);
+
+		err = pds_vfio_get_lm_state_cmd(pds_vfio);
+		if (err) {
+			pds_vfio_put_save_file(pds_vfio);
+			return ERR_PTR(err);
+		}
+
+		return pds_vfio->save_file->filep;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_STOP_COPY && next == VFIO_DEVICE_STATE_STOP) {
+		pds_vfio_put_save_file(pds_vfio);
+		pds_vfio_send_host_vf_lm_status_cmd(pds_vfio, PDS_LM_STA_NONE);
+		return NULL;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_RESUMING) {
+		err = pds_vfio_get_restore_file(pds_vfio);
+		if (err)
+			return ERR_PTR(err);
+
+		return pds_vfio->restore_file->filep;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_RESUMING && next == VFIO_DEVICE_STATE_STOP) {
+		err = pds_vfio_set_lm_state_cmd(pds_vfio);
+		if (err)
+			return ERR_PTR(err);
+
+		pds_vfio_put_restore_file(pds_vfio);
+		return NULL;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_RUNNING && next == VFIO_DEVICE_STATE_RUNNING_P2P) {
+		pds_vfio_send_host_vf_lm_status_cmd(pds_vfio,
+						    PDS_LM_STA_IN_PROGRESS);
+		err = pds_vfio_suspend_device_cmd(pds_vfio,
+						  PDS_LM_SUSPEND_RESUME_TYPE_P2P);
+		if (err)
+			return ERR_PTR(err);
+
+		return NULL;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_RUNNING_P2P && next == VFIO_DEVICE_STATE_RUNNING) {
+		err = pds_vfio_resume_device_cmd(pds_vfio,
+						 PDS_LM_SUSPEND_RESUME_TYPE_FULL);
+		if (err)
+			return ERR_PTR(err);
+
+		pds_vfio_send_host_vf_lm_status_cmd(pds_vfio, PDS_LM_STA_NONE);
+		return NULL;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_STOP && next == VFIO_DEVICE_STATE_RUNNING_P2P) {
+		err = pds_vfio_resume_device_cmd(pds_vfio,
+						 PDS_LM_SUSPEND_RESUME_TYPE_P2P);
+		if (err)
+			return ERR_PTR(err);
+
+		return NULL;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_RUNNING_P2P && next == VFIO_DEVICE_STATE_STOP) {
+		err = pds_vfio_suspend_device_cmd(pds_vfio,
+						  PDS_LM_SUSPEND_RESUME_TYPE_FULL);
+		if (err)
+			return ERR_PTR(err);
+		return NULL;
+	}
+
+	return ERR_PTR(-EINVAL);
+}
diff --git a/drivers/vfio/pci/pds/lm.h b/drivers/vfio/pci/pds/lm.h
new file mode 100644
index 000000000000..13be893198b7
--- /dev/null
+++ b/drivers/vfio/pci/pds/lm.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2023 Advanced Micro Devices, Inc. */
+
+#ifndef _LM_H_
+#define _LM_H_
+
+#include <linux/fs.h>
+#include <linux/mutex.h>
+#include <linux/scatterlist.h>
+#include <linux/types.h>
+
+#include <linux/pds/pds_common.h>
+#include <linux/pds/pds_adminq.h>
+
+struct pds_vfio_lm_file {
+	struct file *filep;
+	struct mutex lock;	/* protect live migration data file */
+	u64 size;		/* Size with valid data */
+	u64 alloc_size;		/* Total allocated size. Always >= len */
+	void *page_mem;		/* memory allocated for pages */
+	struct page **pages;	/* Backing pages for file */
+	unsigned long long npages;
+	struct sg_table sg_table;	/* SG table for backing pages */
+	struct pds_lm_sg_elem *sgl;	/* DMA mapping */
+	dma_addr_t sgl_addr;
+	u16 num_sge;
+	struct scatterlist *last_offset_sg;	/* Iterator */
+	unsigned int sg_last_entry;
+	unsigned long last_offset;
+};
+
+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);
+
+void pds_vfio_put_save_file(struct pds_vfio_pci_device *pds_vfio);
+void pds_vfio_put_restore_file(struct pds_vfio_pci_device *pds_vfio);
+
+#endif /* _LM_H_ */
diff --git a/drivers/vfio/pci/pds/pci_drv.c b/drivers/vfio/pci/pds/pci_drv.c
index d9d2725e2faa..03989f02a1f4 100644
--- a/drivers/vfio/pci/pds/pci_drv.c
+++ b/drivers/vfio/pci/pds/pci_drv.c
@@ -67,11 +67,24 @@ static const struct pci_device_id pds_vfio_pci_table[] = {
 };
 MODULE_DEVICE_TABLE(pci, pds_vfio_pci_table);
 
+static void pds_vfio_pci_aer_reset_done(struct pci_dev *pdev)
+{
+	struct pds_vfio_pci_device *pds_vfio = pds_vfio_pci_drvdata(pdev);
+
+	pds_vfio_reset(pds_vfio);
+}
+
+static const struct pci_error_handlers pds_vfio_pci_err_handlers = {
+	.reset_done = pds_vfio_pci_aer_reset_done,
+	.error_detected = vfio_pci_core_aer_err_detected,
+};
+
 static struct pci_driver pds_vfio_pci_driver = {
 	.name = KBUILD_MODNAME,
 	.id_table = pds_vfio_pci_table,
 	.probe = pds_vfio_pci_probe,
 	.remove = pds_vfio_pci_remove,
+	.err_handler = &pds_vfio_pci_err_handlers,
 	.driver_managed_dma = true,
 };
 
diff --git a/drivers/vfio/pci/pds/vfio_dev.c b/drivers/vfio/pci/pds/vfio_dev.c
index ce42f0b461b3..b37ef96a7fd8 100644
--- a/drivers/vfio/pci/pds/vfio_dev.c
+++ b/drivers/vfio/pci/pds/vfio_dev.c
@@ -4,6 +4,7 @@
 #include <linux/vfio.h>
 #include <linux/vfio_pci_core.h>
 
+#include "lm.h"
 #include "vfio_dev.h"
 
 struct pci_dev *pds_vfio_to_pci_dev(struct pds_vfio_pci_device *pds_vfio)
@@ -11,6 +12,11 @@ struct pci_dev *pds_vfio_to_pci_dev(struct pds_vfio_pci_device *pds_vfio)
 	return pds_vfio->vfio_coredev.pdev;
 }
 
+struct device *pds_vfio_to_dev(struct pds_vfio_pci_device *pds_vfio)
+{
+	return &pds_vfio_to_pci_dev(pds_vfio)->dev;
+}
+
 struct pds_vfio_pci_device *pds_vfio_pci_drvdata(struct pci_dev *pdev)
 {
 	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
@@ -19,6 +25,98 @@ struct pds_vfio_pci_device *pds_vfio_pci_drvdata(struct pci_dev *pdev)
 			    vfio_coredev);
 }
 
+static void pds_vfio_state_mutex_unlock(struct pds_vfio_pci_device *pds_vfio)
+{
+again:
+	spin_lock(&pds_vfio->reset_lock);
+	if (pds_vfio->deferred_reset) {
+		pds_vfio->deferred_reset = false;
+		if (pds_vfio->state == VFIO_DEVICE_STATE_ERROR) {
+			pds_vfio->state = VFIO_DEVICE_STATE_RUNNING;
+			pds_vfio_put_restore_file(pds_vfio);
+			pds_vfio_put_save_file(pds_vfio);
+		}
+		spin_unlock(&pds_vfio->reset_lock);
+		goto again;
+	}
+	mutex_unlock(&pds_vfio->state_mutex);
+	spin_unlock(&pds_vfio->reset_lock);
+}
+
+void pds_vfio_reset(struct pds_vfio_pci_device *pds_vfio)
+{
+	spin_lock(&pds_vfio->reset_lock);
+	pds_vfio->deferred_reset = true;
+	if (!mutex_trylock(&pds_vfio->state_mutex)) {
+		spin_unlock(&pds_vfio->reset_lock);
+		return;
+	}
+	spin_unlock(&pds_vfio->reset_lock);
+	pds_vfio_state_mutex_unlock(pds_vfio);
+}
+
+static struct file *
+pds_vfio_set_device_state(struct vfio_device *vdev,
+			  enum vfio_device_mig_state new_state)
+{
+	struct pds_vfio_pci_device *pds_vfio =
+		container_of(vdev, struct pds_vfio_pci_device,
+			     vfio_coredev.vdev);
+	struct file *res = NULL;
+
+	mutex_lock(&pds_vfio->state_mutex);
+	while (new_state != pds_vfio->state) {
+		enum vfio_device_mig_state next_state;
+
+		int err = vfio_mig_get_next_state(vdev, pds_vfio->state,
+						  new_state, &next_state);
+		if (err) {
+			res = ERR_PTR(err);
+			break;
+		}
+
+		res = pds_vfio_step_device_state_locked(pds_vfio, next_state);
+		if (IS_ERR(res))
+			break;
+
+		pds_vfio->state = next_state;
+
+		if (WARN_ON(res && new_state != pds_vfio->state)) {
+			res = ERR_PTR(-EINVAL);
+			break;
+		}
+	}
+	pds_vfio_state_mutex_unlock(pds_vfio);
+
+	return res;
+}
+
+static int pds_vfio_get_device_state(struct vfio_device *vdev,
+				     enum vfio_device_mig_state *current_state)
+{
+	struct pds_vfio_pci_device *pds_vfio =
+		container_of(vdev, struct pds_vfio_pci_device,
+			     vfio_coredev.vdev);
+
+	mutex_lock(&pds_vfio->state_mutex);
+	*current_state = pds_vfio->state;
+	pds_vfio_state_mutex_unlock(pds_vfio);
+	return 0;
+}
+
+static int pds_vfio_get_device_state_size(struct vfio_device *vdev,
+					  unsigned long *stop_copy_length)
+{
+	*stop_copy_length = PDS_LM_DEVICE_STATE_LENGTH;
+	return 0;
+}
+
+static const struct vfio_migration_ops pds_vfio_lm_ops = {
+	.migration_set_state = pds_vfio_set_device_state,
+	.migration_get_state = pds_vfio_get_device_state,
+	.migration_get_data_size = pds_vfio_get_device_state_size
+};
+
 static int pds_vfio_init_device(struct vfio_device *vdev)
 {
 	struct pds_vfio_pci_device *pds_vfio =
@@ -37,6 +135,9 @@ static int pds_vfio_init_device(struct vfio_device *vdev)
 
 	pds_vfio->vf_id = vf_id;
 
+	vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P;
+	vdev->mig_ops = &pds_vfio_lm_ops;
+
 	pci_id = PCI_DEVID(pdev->bus->number, pdev->devfn);
 	dev_dbg(&pdev->dev,
 		"%s: PF %#04x VF %#04x vf_id %d domain %d pds_vfio %p\n",
@@ -57,17 +158,34 @@ static int pds_vfio_open_device(struct vfio_device *vdev)
 	if (err)
 		return err;
 
+	mutex_init(&pds_vfio->state_mutex);
+	pds_vfio->state = VFIO_DEVICE_STATE_RUNNING;
+
 	vfio_pci_core_finish_enable(&pds_vfio->vfio_coredev);
 
 	return 0;
 }
 
+static void pds_vfio_close_device(struct vfio_device *vdev)
+{
+	struct pds_vfio_pci_device *pds_vfio =
+		container_of(vdev, struct pds_vfio_pci_device,
+			     vfio_coredev.vdev);
+
+	mutex_lock(&pds_vfio->state_mutex);
+	pds_vfio_put_restore_file(pds_vfio);
+	pds_vfio_put_save_file(pds_vfio);
+	mutex_unlock(&pds_vfio->state_mutex);
+	mutex_destroy(&pds_vfio->state_mutex);
+	vfio_pci_core_close_device(vdev);
+}
+
 static const struct vfio_device_ops pds_vfio_ops = {
 	.name = "pds-vfio",
 	.init = pds_vfio_init_device,
 	.release = vfio_pci_core_release_dev,
 	.open_device = pds_vfio_open_device,
-	.close_device = vfio_pci_core_close_device,
+	.close_device = pds_vfio_close_device,
 	.ioctl = vfio_pci_core_ioctl,
 	.device_feature = vfio_pci_core_ioctl_feature,
 	.read = vfio_pci_core_read,
diff --git a/drivers/vfio/pci/pds/vfio_dev.h b/drivers/vfio/pci/pds/vfio_dev.h
index ba4ee8c0eda3..53ba1dd3cb92 100644
--- a/drivers/vfio/pci/pds/vfio_dev.h
+++ b/drivers/vfio/pci/pds/vfio_dev.h
@@ -7,16 +7,27 @@
 #include <linux/pci.h>
 #include <linux/vfio_pci_core.h>
 
+#include "lm.h"
+
 struct pds_vfio_pci_device {
 	struct vfio_pci_core_device vfio_coredev;
 
+	struct pds_vfio_lm_file *save_file;
+	struct pds_vfio_lm_file *restore_file;
+	struct mutex state_mutex; /* protect migration state */
+	enum vfio_device_mig_state state;
+	spinlock_t reset_lock; /* protect reset_done flow */
+	u8 deferred_reset;
+
 	int vf_id;
 	u16 client_id;
 };
 
 const struct vfio_device_ops *pds_vfio_ops_info(void);
 struct pds_vfio_pci_device *pds_vfio_pci_drvdata(struct pci_dev *pdev);
+void pds_vfio_reset(struct pds_vfio_pci_device *pds_vfio);
 
 struct pci_dev *pds_vfio_to_pci_dev(struct pds_vfio_pci_device *pds_vfio);
+struct device *pds_vfio_to_dev(struct pds_vfio_pci_device *pds_vfio);
 
 #endif /* _VFIO_DEV_H_ */