doc: Grammatical updates to SR-IOV virt doc

Signed-off-by: Deb Taylor <deb.taylor@intel.com>

doc/tutorials/sriov_virtualization.rst

@@ -4,174 +4,166 @@ SR-IOV Virtualization
 =====================
 
 SR-IOV (Single Root Input/Output Virtualization) can isolate PCIe devices
-and make the devices to have good performance, close to bare-metal. The
+to improve performance that is similar to bare-metal levels. SR-IOV consists
-SR-IOV consists of two basic units, one is called PF(Physical Function)
+of two basic units: PF (Physical Function), which supports SR-IOV PCIe
-that supports SR-IOV PCIe extended capability and manages entire
+extended capability and manages entire physical devices; and VF (Virtual
-physical device, another is called VF (Virtual Function) and is a
+Function), a "lightweight" PCIe function which is a passthrough device for
-"lightweight" PCIe function which is meant to be given to a VM as a
+VMs.
-pass-through device.
 
-For more details, please refer to PCI Express Base Specification Revision 4.0,
+For details, refer to Chapter 9 of PCI-SIG's `PCI Express Base SpecificationRevision 4.0, Version 1.0 <https://pcisig.com/pci-express-architecture-configuration-space-test-specification-revision-40-version-10>`_.
-Version 1.0 `PCI-SIG Specification <https://pcisig.com/specifications>` Chapter 9.
 
 SR-IOV Architectural Overview
 -----------------------------
 
 .. figure:: images/sriov-image1.png
    :align: center
-   :width: 900px
    :name: SR-IOV-architecture-overview
 
    SR-IOV Architectural Overview
 
--  **SI** - System Image known as a VM.
+-  **SI** - A System Image known as a VM.
 
--  **VI** - Virtualization Intermediary known as Hypervisor.
+-  **VI** - A Virtualization Intermediary known as a hypervisor.
 
--  **SR-PCIM** - Single Root PCI Manager is a software entity for SR-IOV
+-  **SR-PCIM** - A Single Root PCI Manager; it is a software entity for
-   management.
+   SR-IOV management.
 
--  **PF** - A PF is a PCIe Function that supports the SR-IOV capability
+-  **PF** - A PCIe Function that supports the SR-IOV capability
    and is accessible to an SR-PCIM, a VI, or an SI.
 
--  **VF** - A VF is a “light-weight” PCIe Function that is directly
+-  **VF** - A “light-weight” PCIe Function that is directly accessible by an
-   accessible by an SI.
+   SI.
 
 SR-IOV Extended Capability
 --------------------------
 
 The SR-IOV Extended Capability defined here is a PCIe extended
-capability that must be implemented in each PF device that supports
+capability that must be implemented in each PF device that supports the
-SR-IOV feature. This Capability is used to describe and control a PF’s
+SR-IOV feature. This capability is used to describe and control a PF’s
 SR-IOV Capabilities.
 
 .. figure:: images/sriov-image2.png
    :align: center
-   :width: 900px
    :name: SR-IOV-extended-capability
 
    SR-IOV Extended Capability
 
 -  **PCIe Extended Capability ID** - 0010h.
 
--  **SR-IOV Capabilities** - VF Migration Capable and ARI Capable.
+-  **SR-IOV Capabilities** - VF Migration-Capable and ARI-Capable.
 
--  **SR-IOV Control** - Enable/Disable VFs, VF migration state query.
+-  **SR-IOV Control** - Enable/Disable VFs; VF migration state query.
 
--  **SR-IOV Status** - VF Migration Status
+-  **SR-IOV Status** - VF Migration Status.
 
--  **InitialVFs** - Indicates to SR-PCIM the number of VFs that are
+-  **InitialVFs** - Indicates to the SR-PCIM the number of VFs that are
-   initially associated with the PF
+   initially associated with the PF.
 
--  **TotalVFs** - Indicates the maximum number of VFs that could be
+-  **TotalVFs** - Indicates the maximum number of VFs that can be
-   associated with the PF
+   associated with the PF.
 
 -  **NumVFs** - Controls the number of VFs that are visible. *NumVFs* <=
    *InitialVFs* = *TotalVFs*.
 
--  **Function Link Dependency** - The field is used to describe these
+-  **Function Link Dependency** - The field used to describe
    dependencies between PFs. VF dependencies are the same as the
    dependencies of their associated PFs.
 
--  **First VF Offset** - It is a constant and defines the Routing ID
+-  **First VF Offset** - A constant that defines the Routing ID
    offset of the first VF that is associated with the PF that contains
-   this Capability structure
+   this Capability structure.
 
--  **VF Stride** - It defines the Routing ID offset from one VF to the
+-  **VF Stride** - Defines the Routing ID offset from one VF to the
    next one for all VFs associated with the PF that contains this
    Capability structure.
 
--  **VF Device ID** - This field contains the Device ID that should be
+-  **VF Device ID** - The field that contains the Device ID that should be
    presented for every VF to the SI.
 
--  **Supported Page Sizes** - This field indicates the page sizes
+-  **Supported Page Sizes** - The field that indicates the page sizes
    supported by the PF.
 
--  **System Page Size** - This field defines the page size the system
+-  **System Page Size** - The field that defines the page size the system
    will use to map the VFs’ memory addresses. Software must set the
    value of the *System Page Size* to one of the page sizes set in the
-   *Supported Page Sizes* field
+   *Supported Page Sizes* field.
 
--  **VF BARs** - These fields must define the VF’s Base Address
+-  **VF BARs** - Fields that must define the VF’s Base Address
    Registers (BARs). These fields behave as normal PCI BARs.
 
--  **VF Migration State Array Offset** - This register shall contain a
+-  **VF Migration State Array Offset** - Register that contains a
    PF BAR relative pointer to the VF Migration State Array.
 
--  **VF Migration State Array** – It is located using the VF Migration
+-  **VF Migration State Array** – Located using the VF Migration
    State Array Offset register of the SR-IOV Capability block.
 
-For more details, please refer to *PCI Express Base Specification
+For details, refer to the *PCI Express Base Specification Revision 4.0, Version 1.0 Chapter 9.3.3*.
-Revision 4.0, Version 1.0 Chapter 9.3.3*
 
 SR-IOV Architecture In ACRN
 ---------------------------
 
 .. figure:: images/sriov-image3.png
    :align: center
-   :width: 900px
    :name: SR-IOV-architecure-in-acrn
 
    SR-IOV Architectural in ACRN
 
-1. Hypervisor detects SR-IOV capable PCIe device in physical PCI device
+1. A hypervisor detects a SR-IOV capable PCIe device in the physical PCI
-   enumeration phase.
+   device enumeration phase.
 
-2. Hypervisor intercepts the PF’s SR-IOV capability accessing to
+2. The hypervisor intercepts the PF’s SR-IOV capability and accesses whether
-   enable/disable VF devices based on *VF\_ENABLE* state, and all
+   to enable/disable VF devices based on the *VF\_ENABLE* state. All
-   read/write requests for PF device are passthrough to PF physical
+   read/write requests for a PF device passthrough to the PF physical
    device.
 
-3. Hypervisor waits for 100ms after *VF\_ENABLE* is set and initialize
+3. The hypervisor waits for 100ms after *VF\_ENABLE* is set and initializes
-   VF devices. The differences between normal passthrough device and
+   VF devices. The differences between a normal passthrough device and
-   SR-IOV VF device are physical device detection, BARs and MSIx
+   SR-IOV VF device are physical device detection, BARs, and MSIx
-   initializations. Hypervisor uses *Subsystem Vendor ID* to detect
+   initialization. The hypervisor uses *Subsystem Vendor ID* to detect the
-   SR-IOV VF physical device instead *Vendor ID* since there is no valid
+   SR-IOV VF physical device instead of *Vendor ID* since no valid
-   *Vendor ID* for SR-IOV VF physical device, the VF BARs are
+   *Vendor ID* exists for the SR-IOV VF physical device. The VF BARs are
-   initialized by its associated PF’s SR-IOV capabilities not PCI
+   initialized by its associated PF’s SR-IOV capabilities, not PCI
-   standard BAR registers, MSIx mapping base address is also from PF’s
+   standard BAR registers. The MSIx mapping base address is also from the
-   SR-IOV capabilities not PCI standard BAR registers.
+   PF’s SR-IOV capabilities, not PCI standard BAR registers.
 
 SR-IOV Passthrough VF Architecture In ACRN
 ------------------------------------------
 
 .. figure:: images/sriov-image4.png
    :align: center
-   :width: 900px
    :name: SR-IOV-vf-passthrough
 
    SR-IOV VF Passthrough Architecture In ACRN
 
-1. The SR-IOV VF device needs to bind PCI-stud driver instead
+1. The SR-IOV VF device needs to bind the PCI-stud driver instead of the
-   vendor-specific VF driver before passthrough the device.
+   vendor-specific VF driver before the device passthrough.
 
-2. User configures ``acrn-dm`` boot parameter with passthrough SR-IOV VF
+2. The user configures the ``acrn-dm`` boot parameter with the passthrough
-   device. When User VM starts, ``acrn-dm`` invokes a hypercall to set the
+   SR-IOV VF device. When the User VM starts, ``acrn-dm`` invokes a
-   *vdev-VF0* device in User VM.
+   hypercall to set the *vdev-VF0* device in the User VM.
 
-3. Hypervisor emulates *Device ID/Vendor ID* and *Memory Space Enable
+3. The hypervisor emulates *Device ID/Vendor ID* and *Memory Space Enable
-   (MSE*) in configuration space for an assigned SR-IOV VF device. The
+   (MSE)* in the configuration space for an assigned SR-IOV VF device. The
-   assigned VF *Device ID* comes from its associated PF’s capability,
+   assigned VF *Device ID* comes from its associated PF’s capability. The
-   *Vendor ID* is same with PF’s *Vendor ID* and *MSE* is always set
+   *Vendor ID* is the same as the PF’s *Vendor ID* and the *MSE* is always
-   when reading the SR-IOV VF device *CONTROL* register
+   set when reading the SR-IOV VF device's *CONTROL* register.
 
-4. Vendor-specific VF driver in target VM probes the assigned SR-IOV VF
+4. The vendor-specific VF driver in the target VM probes the assigned SR-IOV
-   device.
+   VF device.
 
 SR-IOV Initialization Flow
 --------------------------
 
 .. figure:: images/sriov-image5.png
    :align: center
-   :width: 900px
    :name: SR-IOV-init-flow
 
    SR-IOV Initialization Flow
 
 When a SR-IOV capable device is initialized, all access to the
 configuration space will passthrough to the physical device directly.
-Service VM can identify all capabilities of the device from SR-IOV extended
+The Service VM can identify all capabilities of the device from the SR-IOV
-capability then create sysfs node for SR-IOV management.
+extended capability and then create an *sysfs* node for SR-IOV management.
 
 SR-IOV VF Enable Flow
 ---------------------
@@ -183,94 +175,87 @@ SR-IOV VF Enable Flow
 
    SR-IOV VF Enable Flow
 
-Application enables n VF devices via a SR-IOV PF device *sysfs* node.
+The application enables n VF devices via a SR-IOV PF device *sysfs* node.
-Hypervisor intercepts all SR-IOV capability accesses and check
+The hypervisor intercepts all SR-IOV capability access and checks the
-*VF\_ENABLE* state, if the *VF\_ENABLE* is set, hypervisor creates n
+*VF\_ENABLE* state. If *VF\_ENABLE* is set, the hypervisor creates n
-virtual devices after 100ms that VF physical devices have enough time to
+virtual devices after 100ms so that VF physical devices have enough time to
-be created. Service VM waits 100ms then only accesses the first VF device’s
+be created. The Service VM waits 100ms and then only accesses the first VF
-configuration space including *Class Code, Reversion ID, Subsystem
+device’s configuration space including *Class Code, Reversion ID, Subsystem
-Vendor ID, Subsystem ID,* Service VM uses the first VF device information to
+Vendor ID, Subsystem ID*. The Service VM uses the first VF device
-initialize subsequent VF devices.
+information to initialize subsequent VF devices.
 
 SR-IOV VF Disable Flow
 ----------------------
 
 .. figure:: images/sriov-image7.png
    :align: center
-   :width: 900px
    :name: SR-IOV-disable-flow
 
    SR-IOV VF Disable Flow
 
-Application disables SR-IOV VF devices by writing zero to SR-IOV PF
+The application disables SR-IOV VF devices by writing zero to the SR-IOV PF
-device *sysfs* node. Hypervisor intercepts all SR-IOV capability
+device *sysfs* node. The hypervisor intercepts all SR-IOV capability
-accesses and check *VF\_ENABLE* state, if *VF\_ENABLE* is clear,
+accesses and checks the *VF\_ENABLE* state. If *VF\_ENABLE* is clear, the
-hypervisor makes VF virtual devices invisible from Service VM that all accesses
+hypervisor makes VF virtual devices invisible from the Service VM so that all
-for VF will return 0xFFFFFFFF as an error, VF physical devices are
+access to VF devices will return 0xFFFFFFFF as an error. The VF physical
-removed within 1s of *VF\_ENABLE* is clear.
+devices are removed within 1s of when *VF\_ENABLE* is clear.
 
 SR-IOV VF Assignment Policy
 ---------------------------
 
 .. figure:: images/sriov-image8.png
    :align: center
-   :width: 900px
    :name: SR-IOV-vf-assignment
 
    SR-IOV VF Assignment
 
-1. All SR-IOV PF devices are managed by Service VM.
+1. All SR-IOV PF devices are managed by the Service VM.
 
-2. Currently, SR-IOV PF can’t passthrough to User VM.
+2. Currently, the SR-IOV PF cannot passthrough to the User VM.
 
-3. All VFs can be passthrough to User VM, but we do not recommend
+3. All VFs can passthrough to the User VM, but we do not recommend
-   passthrough to high privilege VMs, because PF device may impact
+   a passthrough to high privilege VMs because the PF device may impact
-   assigned VFs including functionality and stability.
+   the assigned VFs' functionality and stability.
 
 SR-IOV Usage Guide In ACRN
 --------------------------
 
-We use Intel 82576 NIC as an example in here and only support LaaG
+We use the Intel 82576 NIC as an example in the following instructions. We
-(Linux as a Guest).
+only support LaaG (Linux as a Guest).
 
-1. Please ensure the 82576 VF driver is compiled into User VM Kernel
+1. Ensure that the 82576 VF driver is compiled into the User VM Kernel
-   (Set *CONFIG\_IGBVF=y* in Kernel Config).
+   (set *CONFIG\_IGBVF=y* in the Kernel Config).
 
-2. When the Service VM boot up, “\ *lspci -v*\ ” command can show Intel 82576
+#. When the Service VM boots up, the ``\ *lspci -v*\`` command indicates
-   NIC devices have SR-IOV capability and their PF drivers are ``igb``.
+   that the Intel 82576 NIC devices have SR-IOV capability and their PF
+   drivers are ``igb``.
 
    .. figure:: images/sriov-image9.png
       :align: center
-   :width: 900px
       :name: 82576-pf
 
       82576 SR-IOV PF devices
 
-1. Input "\ *echo n > /sys/class/net/enp109s0f0/device/sriov\_numvfs*\ "
+#. Input the ``\ *echo n > /sys/class/net/enp109s0f0/device/sriov\_numvfs*\``
-   command in Service VM to enable n VF devices for the first PF
+   command in the Service VM to enable n VF devices for the first PF
-   device(\ *enp109s0f0)*. The number *n* can’t more than *TotalVFs*
+   device (\ *enp109s0f0)*. The number *n* can’t be more than *TotalVFs*
-   that comes from the return value of command
+   which comes from the return value of command ``cat /sys/class/net/enp109s0f0/device/sriov\_totalvfs``. Here we use *n = 2* as an example.
-
-   *“cat /sys/class/net/enp109s0f0/device/sriov\_totalvfs”*. Here we use
-   *n = 2* for the example.
 
    .. figure:: images/sriov-image10.png
       :align: center
-   :width: 900px
       :name: 82576-vf
 
       82576 SR-IOV VF devices
 
    .. figure:: images/sriov-image11.png
       :align: center
-   :width: 900px
       :name: 82576-vf-nic
 
       82576 SR-IOV VF NIC
 
-1. Passthrough a SR-IOV VF device to guest
+#. Passthrough a SR-IOV VF device to guest.
 
-   a. Unbind igbvf driver in Service VM
+   a. Unbind the igbvf driver in the Service VM.
 
       i.   *modprobe pci\_stub*
 
@@ -282,25 +267,25 @@ We use Intel 82576 NIC as an example in here and only support LaaG
       iv.  *echo "0000:6d:10.0" >
            /sys/bus/pci/drivers/pci-stub/bind*
 
-   b. Add SR-IOV VF device parameter (“*-s X, passthru,6d/10/0*\ ”) in
+   b. Add the SR-IOV VF device parameter (“*-s X, passthru,6d/10/0*\ ”) in
-      launch User VM script
+      the launch User VM script
 
       .. figure:: images/sriov-image12.png
          :align: center
-   :width: 900px
          :name: 82576-nic-passthru
 
-   Configure 82576 NIC as Passthrough Device
+         Configure 82576 NIC as a Passthrough Device
 
-a. Boot User VM
+   c. Boot the User VM
 
 SR-IOV Limitations In ACRN
 --------------------------
 
 1. The SR-IOV migration feature is not supported.
 
-2. If one SR-IOV PF device is detected during enumeration phase, but there is no
+2. If one SR-IOV PF device is detected during the enumeration phase, but
-   enough room for its total VF devices, the PF device will be dropped. The platform
+   not enough room exists for its total VF devices, the PF device will be
-   uses *MAX_PCI_DEV_NUM* ACRN configuration to support the maximum number of PCI
+   dropped. The platform uses the *MAX_PCI_DEV_NUM* ACRN configuration to
-   devices, please make sure *MAX_PCI_DEV_NUM* is more than the number of all PCI
+   support the maximum number of PCI devices. Make sure *MAX_PCI_DEV_NUM* is
-   devices including total SR-IOV VF devices.
+   more than the number of all PCI devices, including the total SR-IOV VF
+   devices.