[RFC PATCH 9/9] i40e/vf_migration: support dynamic trap of bar0

From: Yan Zhao
Date: Wed Dec 04 2019 - 22:36:10 EST

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mediate dynamic_trap_info region to dynamically trap bar0.

bar0 is sparsely mmaped into 5 sub-regions, of which only two need to be
dynamically trapped.
By mediating dynamic_trap_info region and telling QEMU this information,
the two sub-regions of bar0 can be trapped when migration starts and put
to passthrough again when migration fails

Cc: Shaopeng He <shaopeng.he@xxxxxxxxx>

Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
---
.../ethernet/intel/i40e/i40e_vf_migration.c | 140 +++++++++++++++++-
.../ethernet/intel/i40e/i40e_vf_migration.h | 12 ++
2 files changed, 147 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_vf_migration.c b/drivers/net/ethernet/intel/i40e/i40e_vf_migration.c
index 5bb509fed66e..0b9d5be85049 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_vf_migration.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_vf_migration.c
@@ -29,6 +29,21 @@ static bool is_handle_valid(int handle)
return true;
}

+static
+void i40e_vf_migration_dynamic_trap_bar(struct i40e_vf_migration *i40e_vf_dev)
+{
+ if (i40e_vf_dev->dt_trigger)
+ eventfd_signal(i40e_vf_dev->dt_trigger, 1);
+}
+
+static void i40e_vf_trap_bar0(struct i40e_vf_migration *i40e_vf_dev, bool trap)
+{
+ if (i40e_vf_dev->trap_bar0 != trap) {
+ i40e_vf_dev->trap_bar0 = trap;
+ i40e_vf_migration_dynamic_trap_bar(i40e_vf_dev);
+ }
+}
+
static size_t set_device_state(struct i40e_vf_migration *i40e_vf_dev, u32 state)
{
int ret = 0;
@@ -39,8 +54,10 @@ static size_t set_device_state(struct i40e_vf_migration *i40e_vf_dev, u32 state)

switch (state) {
case VFIO_DEVICE_STATE_RUNNING:
+ i40e_vf_trap_bar0(i40e_vf_dev, false);
break;
case VFIO_DEVICE_STATE_SAVING | VFIO_DEVICE_STATE_RUNNING:
+ i40e_vf_trap_bar0(i40e_vf_dev, true);
// alloc dirty page tracking resources and
// do the first round dirty page scanning
break;
@@ -137,16 +154,22 @@ int i40e_vf_migration_open(struct pci_dev *pdev, u64 *caps, u32 *dm_handle)
MIGRATION_DIRTY_BITMAP_SIZE;
i40e_vf_dev->migration_region_index = -1;

+ i40e_vf_dev->dt_region_index = -1;
+ i40e_vf_dev->trap_bar0 = false;
+
vf = &pf->vf[vf_id];

i40e_vf_dev_array[handle] = i40e_vf_dev;
set_bit(handle, open_device_bits);
+
*dm_handle = handle;

*caps |= VFIO_PCI_DEVICE_CAP_MIGRATION;
+ *caps |= VFIO_PCI_DEVICE_CAP_DYNAMIC_TRAP_BAR;

pr_info("%s: device %x %x, vf id %d, handle=%x\n",
__func__, pdev->vendor, pdev->device, vf_id, handle);
+
error:
mutex_unlock(&device_bit_lock);

@@ -188,6 +211,10 @@ void i40e_vf_migration_release(int handle)

kfree(i40e_vf_dev->mig_ctl);
vfree(i40e_vf_dev->dirty_bitmap);
+
+ if (i40e_vf_dev->dt_trigger)
+ eventfd_ctx_put(i40e_vf_dev->dt_trigger);
+
kfree(i40e_vf_dev);

module_put(THIS_MODULE);
@@ -216,6 +243,47 @@ static void migration_region_sparse_mmap_cap(struct vfio_info_cap *caps)
kfree(sparse);
}

+static void bar0_sparse_mmap_cap(struct vfio_region_info *info,
+ struct vfio_info_cap *caps)
+{
+ struct vfio_region_info_cap_sparse_mmap *sparse;
+ size_t size;
+ int nr_areas = 5;
+
+ size = sizeof(*sparse) + (nr_areas * sizeof(*sparse->areas));
+
+ sparse = kzalloc(size, GFP_KERNEL);
+ if (!sparse)
+ return;
+
+ sparse->header.id = VFIO_REGION_INFO_CAP_SPARSE_MMAP;
+ sparse->header.version = 1;
+ sparse->nr_areas = nr_areas;
+
+ sparse->areas[0].offset = 0;
+ sparse->areas[0].size = IAVF_VF_TAIL_START;
+ sparse->areas[0].disablable = 0;//able to get toggled
+
+ sparse->areas[1].offset = IAVF_VF_TAIL_START;
+ sparse->areas[1].size = PAGE_SIZE;
+ sparse->areas[1].disablable = 1;//able to get toggled
+
+ sparse->areas[2].offset = IAVF_VF_TAIL_START + PAGE_SIZE;
+ sparse->areas[2].size = IAVF_VF_ARQH1 - sparse->areas[2].offset;
+ sparse->areas[2].disablable = 0;//able to get toggled
+
+ sparse->areas[3].offset = IAVF_VF_ARQT1;
+ sparse->areas[3].size = PAGE_SIZE;
+ sparse->areas[3].disablable = 1;//able to get toggled
+
+ sparse->areas[4].offset = IAVF_VF_ARQT1 + PAGE_SIZE;
+ sparse->areas[4].size = info->size - sparse->areas[4].offset;
+ sparse->areas[4].disablable = 0;//able to get toggled
+
+ vfio_info_add_capability(caps, &sparse->header, size);
+ kfree(sparse);
+}
+
static void
i40e_vf_migration_get_region_info(int handle,
struct vfio_region_info *info,
@@ -227,9 +295,8 @@ i40e_vf_migration_get_region_info(int handle,

switch (info->index) {
case VFIO_PCI_BAR0_REGION_INDEX:
- info->flags = VFIO_REGION_INFO_FLAG_READ |
- VFIO_REGION_INFO_FLAG_WRITE;
-
+ info->flags |= VFIO_REGION_INFO_FLAG_MMAP;
+ bar0_sparse_mmap_cap(info, caps);
break;
case VFIO_PCI_BAR1_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
case VFIO_PCI_CONFIG_REGION_INDEX:
@@ -237,7 +304,20 @@ i40e_vf_migration_get_region_info(int handle,
case VFIO_PCI_VGA_REGION_INDEX:
break;
default:
- if (cap_type->type == VFIO_REGION_TYPE_MIGRATION &&
+ if (cap_type->type ==
+ VFIO_REGION_TYPE_DYNAMIC_TRAP_BAR_INFO &&
+ cap_type->subtype ==
+ VFIO_REGION_SUBTYPE_DYNAMIC_TRAP_BAR_INFO) {
+ struct i40e_vf_migration *i40e_vf_dev;
+
+ i40e_vf_dev = i40e_vf_dev_array[handle];
+ i40e_vf_dev->dt_region_index = info->index;
+ info->size =
+ sizeof(struct vfio_device_dt_bar_info_region);
+ } else if ((cap_type->type == VFIO_REGION_TYPE_MIGRATION) &&
+ (cap_type->subtype ==
+ VFIO_REGION_SUBTYPE_MIGRATION)) {
+ } else if (cap_type->type == VFIO_REGION_TYPE_MIGRATION &&
cap_type->subtype == VFIO_REGION_SUBTYPE_MIGRATION) {
struct i40e_vf_migration *i40e_vf_dev;

@@ -254,6 +334,53 @@ i40e_vf_migration_get_region_info(int handle,
}
}

+static ssize_t i40e_vf_dt_region_rw(struct i40e_vf_migration *i40e_vf_dev,
+ char __user *buf, size_t count,
+ loff_t *ppos, bool iswrite, bool *pt)
+{
+#define DT_REGION_OFFSET(x) offsetof(struct vfio_device_dt_bar_info_region, x)
+ u64 pos = *ppos & VFIO_PCI_OFFSET_MASK;
+ ssize_t ret = 0;
+
+ *pt = false;
+ switch (pos) {
+ case DT_REGION_OFFSET(dt_fd):
+ if (iswrite) {
+ u32 dt_fd;
+ struct eventfd_ctx *trigger;
+
+ if (copy_from_user(&dt_fd, buf, sizeof(dt_fd)))
+ return -EFAULT;
+
+ trigger = eventfd_ctx_fdget(dt_fd);
+ if (IS_ERR(trigger)) {
+ pr_err("i40e_vf_migration_rw, dt trigger fd set error\n");
+ return -EINVAL;
+ }
+ i40e_vf_dev->dt_trigger = trigger;
+ ret = sizeof(dt_fd);
+ } else {
+ ret = -EFAULT;
+ }
+ break;
+
+ case DT_REGION_OFFSET(trap):
+ if (iswrite)
+ ret = copy_from_user(&i40e_vf_dev->trap_bar0,
+ buf, count) ? -EFAULT : count;
+ else
+ ret = copy_to_user(buf,
+ &i40e_vf_dev->trap_bar0,
+ sizeof(u32)) ?
+ -EFAULT : sizeof(u32);
+ break;
+ default:
+ ret = -EFAULT;
+ break;
+ }
+ return ret;
+}
+
static
ssize_t i40e_vf_migration_region_rw(struct i40e_vf_migration *i40e_vf_dev,
char __user *buf, size_t count,
@@ -420,7 +547,10 @@ static ssize_t i40e_vf_migration_rw(int handle, char __user *buf,
case VFIO_PCI_VGA_REGION_INDEX:
break;
default:
- if (index == i40e_vf_dev->migration_region_index) {
+ if (index == i40e_vf_dev->dt_region_index) {
+ return i40e_vf_dt_region_rw(i40e_vf_dev, buf, count,
+ ppos, iswrite, pt);
+ } else if (index == i40e_vf_dev->migration_region_index) {
return i40e_vf_migration_region_rw(i40e_vf_dev, buf,
count, ppos, iswrite, pt);
}
diff --git a/drivers/net/ethernet/intel/i40e/i40e_vf_migration.h b/drivers/net/ethernet/intel/i40e/i40e_vf_migration.h
index b31b500b3cd6..dfad4cc7e46f 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_vf_migration.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_vf_migration.h
@@ -21,6 +21,14 @@
PAGE_ALIGN(sizeof(struct vfio_device_migration_info))
#define MIGRATION_DIRTY_BITMAP_SIZE (64 * 1024UL)

+#define IAVF_VF_ARQBAH1 0x00006000 /* Reset: EMPR */
+#define IAVF_VF_ARQBAL1 0x00006C00 /* Reset: EMPR */
+#define IAVF_VF_ARQH1 0x00007400 /* Reset: EMPR */
+#define IAVF_VF_ARQT1 0x00007000 /* Reset: EMPR */
+#define IAVF_VF_ARQLEN1 0x00008000 /* Reset: EMPR */
+#define IAVF_VF_TAIL_START 0x00002000 /* Start of tail register region */
+#define IAVF_VF_TAIL_END 0x00002400 /* End of tail register region */
+
/* Single Root I/O Virtualization */
struct pci_sriov {
int pos; /* Capability position */
@@ -56,6 +64,10 @@ struct i40e_vf_migration {
struct pci_dev *vf_dev;
int vf_id;

+ __u64 dt_region_index;
+ struct eventfd_ctx *dt_trigger;
+ bool trap_bar0;
+
__u64 migration_region_index;
__u64 migration_region_size;

--
2.17.1

Next message: Randy Dunlap: "Re: [PATCH 2/2] fix the SPDX syntax and bash interprester pointer"
Previous message: Yan Zhao: "[RFC PATCH 8/9] i40e/vf_migration: mediate migration region"
In reply to: Yan Zhao: "[RFC PATCH 8/9] i40e/vf_migration: mediate migration region"
Next in thread: Jason Wang: "Re: [RFC PATCH 0/9] Introduce mediate ops in vfio-pci"
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