[PATCH v5 7/7] RFC: add initial support for configuring feature bits

[Max Gurtovoy <mgurtovoy@nvidia.com>]

After adding the concept of a management and a managed device, add
another example of using this concept to manage resources.

Today there is no standard definition in the spec that allows user to
setup specific feature bits of a virtio device.

For that, extend the management mechanism to allow management devices to
change feature bits of its managed devices.

Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
---
 admin.tex | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/admin.tex b/admin.tex
index 5b54743..43106ba 100644
--- a/admin.tex
+++ b/admin.tex
@@ -113,7 +113,9 @@ \subsection{VIRTIO ADMIN DEVICE CAPS IDENTIFY command}\label{sec:Basic Facilitie
         * Bit 0 - if set, the device is a management device
         * Bit 1 - if set, the device is a type 1 management device that supports
         *         MSI-X vector mgmt of its type 1 managed devices
-        * Bits 2 - 63 - reserved for future capabilities.
+        * Bit 2 - if set, the device is a type 1 management device that supports
+        *         feature mgmt of bits 0 to 63 for its type 1 managed devices
+        * Bits 3 - 63 - reserved for future capabilities.
         */
        le64 device_admin_caps;
        u8 reserved[112];
@@ -143,7 +145,9 @@ \subsection{VIRTIO ADMIN DEVICE CAPS ACCEPT command}\label{sec:Basic Facilities
         * Bit 0 - if set, the driver accepted the device as a management device
         * Bit 1 - if set, the driver accepted the device as a type 1 management device
         *         that supports MSI-X vector mgmt of its type 1 managed devices
-        * Bits 2 - 63 - reserved for future capabilities.
+        * Bit 2 - if set, the driver accepted the device as a type 1 management device
+        *         that supports feature mgmt of bits 0 to 63 for its type 1 managed devices
+        * Bits 3 - 63 - reserved for future capabilities.
         */
        le64 driver_admin_caps;
        u8 reserved[112];
@@ -167,12 +171,14 @@ \subsection{VIRTIO ADMIN DEVICE MGMT command}\label{sec:Basic Facilities of a Vi
         u8 operation;
         /*
          * 0 - MSI-X vector
-         * 1 - 65535 are reserved
+         * 1 - Device feature bits 0 to 63
+         * 2 - 65535 are reserved
          */
         le16 resource;
         /*
          * The value to the given resource:
          * if resource = 0 (MSI-X vector), it's a 1-based count.
+         * if resource = 1 (Device feature bits 0 to 63), it's a feature bitmap.
          */
         le64 resource_val;
         u8 reserved[5];
-- 
2.21.0