[virtio-comment] [PATCH v2 8/8] admin: Add requirements of write reporting commands

[Parav Pandit <parav@nvidia.com>]

Add device and driver requirements for the write reporting commands.

Fixes: https://github.com/oasis-tcs/virtio-spec/issues/176
Signed-off-by: Parav Pandit <parav@nvidia.com>
---
changelog:
- addressed comments from Michael
- renamed iova range to a page
- removed duplicate device requirement
- allow stopping write recording multiple times even if it is stopped
  so migration driver can start cleanly at beginning
---
 admin-cmds-device-migration.tex | 36 +++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/admin-cmds-device-migration.tex b/admin-cmds-device-migration.tex
index 992d6ec..01826c7 100644
--- a/admin-cmds-device-migration.tex
+++ b/admin-cmds-device-migration.tex
@@ -581,6 +581,34 @@ \subsubsection{Device Migration}\label{sec:Basic Facilities of a Virtio Device /
 VIRTIO_ADMIN_CMD_DEV_CTX_WRITE data and the length of the field
 in the device.
 
+A device MUST either support all of, or none of
+VIRTIO_ADMIN_CMD_DEV_WRITE_RECORD_CAP_QUERY,
+VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_START,
+VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_STOP and
+VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_READ commands.
+
+If the device supports VIRTIO_ADMIN_CMD_DEV_WRITE_RECORD_CAP_QUERY
+command, the device MUST set minimum one bit in the
+\field{supported_page_size_bitmap} and set non zero value in the
+\field{supported_ranges}.
+
+The device MUST fail VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_READ command
+if the write recording is not started by the driver.
+
+The device MUST complete VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_STOP command
+successfully, even if the write recording is not started by the driver
+or write recording is already stopped previously.
+
+For the SR-IOV group type, for the VF member device, VF function level
+reset (FLR) MUST NOT stop write recording on the VF device and it MUST NOT
+clear any write records already gathered by the owner device.
+
+The device MUST clear the write records which are returned in the
+VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_READ result. After command completion
+of VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_READ if new write record is created
+for the same page, the device MUST report such a write record as
+new entry.
+
 \drivernormative{\paragraph}{Device Migration}{Basic Facilities of a Virtio Device / Device groups / Group administration commands / Device Migration}
 
 The driver SHOULD read the complete device context using one or multiple
@@ -603,3 +631,11 @@ \subsubsection{Device Migration}\label{sec:Basic Facilities of a Virtio Device /
 For the SR-IOV group type, the driver MUST NOT write into the
 VIRTIO_PCI_CAP_PCI_CFG capability area when the device mode is set to
 \field{Freeze}.
+
+The driver MUST NOT invoke VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_START
+for overlapping page ranges, each page range supplied in the command
+MUST be supply unique ranges.
+
+If the write recording is started by the driver using
+VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_START commands, the driver MUST explicitly
+stop the wrie recording using VIRTIO_ADMIN_CMD_DEV_WRITE_RECORDS_STOP command.
-- 
2.34.1


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