virtio — archive

[Michael S. Tsirkin <mgurtovoy@nvidia.com>]

On Wed, Apr 27, 2022 at 01:58:24AM +0300, Max Gurtovoy wrote: > 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> Please, add more explanation here. E.g. I am guessing these are host feature bits, right? How does driver know which features are ok to enable? I would expect some description sections and conformance sections. > --- > 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