search for: desc_hw

...for > af_packet as well. Here's the repost (slightly cut down) sorry about the duplicates. The idea is to have a r/w descriptor in a ring structure, replacing the used and available ring, index and descriptor buffer. * Descriptor ring: Guest adds descriptors with unique index values and DESC_HW set in flags. Host overwrites used descriptors with correct len, index, and DESC_HW clear. Flags are always set/cleared last. #define DESC_HW 0x0080 struct desc { __le64 addr; __le32 len; __le16 index; __le16 flags; }; When DESC_HW is set, descriptor belongs to d...

...for > af_packet as well. Here's the repost (slightly cut down) sorry about the duplicates. The idea is to have a r/w descriptor in a ring structure, replacing the used and available ring, index and descriptor buffer. * Descriptor ring: Guest adds descriptors with unique index values and DESC_HW set in flags. Host overwrites used descriptors with correct len, index, and DESC_HW clear. Flags are always set/cleared last. #define DESC_HW 0x0080 struct desc { __le64 addr; __le32 len; __le16 index; __le16 flags; }; When DESC_HW is set, descriptor belongs to d...

...erformance analysis of this is in my kvm forum 2016 presentation. > The idea is to have a r/w descriptor in a ring structure, > replacing the used and available ring, index and descriptor > buffer. > > * Descriptor ring: > > Guest adds descriptors with unique index values and DESC_HW set in flags. > Host overwrites used descriptors with correct len, index, and DESC_HW > clear. Flags are always set/cleared last. > > #define DESC_HW 0x0080 > > struct desc { > __le64 addr; > __le32 len; > __le16 index; > __le16 flags...

On Tue, Aug 01, 2017 at 08:54:27PM -0700, Steven Luong wrote: > * Descriptor ring: > > Guest adds descriptors with unique index values and DESC_HW set in flags. > Host overwrites used descriptors with correct len, index, and DESC_HW > clear.? Flags are always set/cleared last. > > #define DESC_HW 0x0080 > > struct desc { > ? ? ? ? __le64 addr; > ? ? ? ? __le32 len; > ? ? ? ? __le16 inde...

On Tue, Aug 01, 2017 at 08:54:27PM -0700, Steven Luong wrote: > * Descriptor ring: > > Guest adds descriptors with unique index values and DESC_HW set in flags. > Host overwrites used descriptors with correct len, index, and DESC_HW > clear.? Flags are always set/cleared last. > > #define DESC_HW 0x0080 > > struct desc { > ? ? ? ? __le64 addr; > ? ? ? ? __le32 len; > ? ? ? ? __le16 inde...

...t; > > The idea is to have a r/w descriptor in a ring structure, > > > replacing the used and available ring, index and descriptor > > > buffer. > > > > > > * Descriptor ring: > > > > > > Guest adds descriptors with unique index values and DESC_HW set in flags. > > > Host overwrites used descriptors with correct len, index, and DESC_HW > > > clear. Flags are always set/cleared last. > > > > > > #define DESC_HW 0x0080 > > > > > > struct desc { > > > __le64 addr; > >...

...t; > > The idea is to have a r/w descriptor in a ring structure, > > > replacing the used and available ring, index and descriptor > > > buffer. > > > > > > * Descriptor ring: > > > > > > Guest adds descriptors with unique index values and DESC_HW set in flags. > > > Host overwrites used descriptors with correct len, index, and DESC_HW > > > clear. Flags are always set/cleared last. > > > > > > #define DESC_HW 0x0080 > > > > > > struct desc { > > > __le64 addr; > >...

...y kvm forum 2016 presentation. > > The idea is to have a r/w descriptor in a ring structure, > > replacing the used and available ring, index and descriptor > > buffer. > > > > * Descriptor ring: > > > > Guest adds descriptors with unique index values and DESC_HW set in flags. > > Host overwrites used descriptors with correct len, index, and DESC_HW > > clear. Flags are always set/cleared last. > > May I know what's the index intended for? Back referencing a pkt buffer? Yes and generally identify which descriptor completed. Recall t...

...y kvm forum 2016 presentation. > > The idea is to have a r/w descriptor in a ring structure, > > replacing the used and available ring, index and descriptor > > buffer. > > > > * Descriptor ring: > > > > Guest adds descriptors with unique index values and DESC_HW set in flags. > > Host overwrites used descriptors with correct len, index, and DESC_HW > > clear. Flags are always set/cleared last. > > May I know what's the index intended for? Back referencing a pkt buffer? Yes and generally identify which descriptor completed. Recall t...

...y kvm forum 2016 presentation. > > The idea is to have a r/w descriptor in a ring structure, > > replacing the used and available ring, index and descriptor > > buffer. > > > > * Descriptor ring: > > > > Guest adds descriptors with unique index values and DESC_HW set in flags. > > Host overwrites used descriptors with correct len, index, and DESC_HW > > clear. Flags are always set/cleared last. > > > > #define DESC_HW 0x0080 > > > > struct desc { > > __le64 addr; > > __le32 len; > >...

...ter writing this entry. + */ +static inline bool need_event(unsigned short event, + unsigned short next, + unsigned short prev) +{ + return (unsigned short)(next - event - 1) < (unsigned short)(next - prev); +} + +/* Design: + * Guest adds descriptors with unique index values and DESC_HW in flags. + * Host overwrites used descriptors with correct len, index, and DESC_HW clear. + * Flags are always set last. + */ +#define DESC_HW 0x1 + +struct desc { + unsigned short flags; + unsigned short index; + unsigned len; + unsigned long long addr; +}; + +/* how much padding is needed to avo...

...ter writing this entry. + */ +static inline bool need_event(unsigned short event, + unsigned short next, + unsigned short prev) +{ + return (unsigned short)(next - event - 1) < (unsigned short)(next - prev); +} + +/* Design: + * Guest adds descriptors with unique index values and DESC_HW in flags. + * Host overwrites used descriptors with correct len, index, and DESC_HW clear. + * Flags are always set last. + */ +#define DESC_HW 0x1 + +struct desc { + unsigned short flags; + unsigned short index; + unsigned len; + unsigned long long addr; +}; + +/* how much padding is needed to avo...

...s/g - lots of new features --- Performance analysis of this is in my kvm forum 2016 presentation. The idea is to have a r/w descriptor in a ring structure, replacing the used and available ring, index and descriptor buffer. * Descriptor ring: Guest adds descriptors with unique index values and DESC_HW set in flags. Host overwrites used descriptors with correct len, index, and DESC_HW clear. Flags are always set/cleared last. #define DESC_HW 0x0080 struct desc { __le64 addr; __le32 len; __le16 index; __le16 flags; }; When DESC_HW is set, descriptor belongs to d...

...s/g - lots of new features --- Performance analysis of this is in my kvm forum 2016 presentation. The idea is to have a r/w descriptor in a ring structure, replacing the used and available ring, index and descriptor buffer. * Descriptor ring: Guest adds descriptors with unique index values and DESC_HW set in flags. Host overwrites used descriptors with correct len, index, and DESC_HW clear. Flags are always set/cleared last. #define DESC_HW 0x0080 struct desc { __le64 addr; __le32 len; __le16 index; __le16 flags; }; When DESC_HW is set, descriptor belongs to d...

...ng, > device writing used entries in a write-only device descriptor ring. > > TODO: does this have any value for some? E.g. as a security feature? > > > * Descriptor ring: > > Driver writes descriptors with unique index values and DESC_DRIVER set in flags. You probably mean DESC_HW here? > Descriptors are written in a ring order: from start to end of ring, > wrapping around to the beginning. > Device writes used descriptors with correct len, index, and DESC_HW clear. > Again descriptors are written in ring order. This might not be the same > order of driver de...

On Wed, Mar 01, 2017 at 11:57:15AM +0800, Yuanhan Liu wrote: > On Wed, Mar 01, 2017 at 03:02:29AM +0200, Michael S. Tsirkin wrote: > > > > * Descriptor ring: > > > > > > > > Guest adds descriptors with unique index values and DESC_HW set in flags. > > > > Host overwrites used descriptors with correct len, index, and DESC_HW > > > > clear. Flags are always set/cleared last. > > > > > > May I know what's the index intended for? Back referencing a pkt buffer? > > > > Yes...

...gt;> Steve > > >Hmm no, not what I had in mind. > >DESC_DRIVER: used by driver to poll. Driver sets it when writing a >descriptor. Device clears it when overwriting a descriptor. >Thus driver uses DESC_DRIVER to detect that device data in >descriptor is valid. Basically DESC_HW from v2 split in two? > >DESC_WRAP: used by device to poll. Driver sets it to a *different* >value every time it overwrites a descriptor. >How to achieve it? >since descriptors are written out in ring order, >simply maintain the current value internally (start value 1) and flip...

...gt;> Steve > > >Hmm no, not what I had in mind. > >DESC_DRIVER: used by driver to poll. Driver sets it when writing a >descriptor. Device clears it when overwriting a descriptor. >Thus driver uses DESC_DRIVER to detect that device data in >descriptor is valid. Basically DESC_HW from v2 split in two? > >DESC_WRAP: used by device to poll. Driver sets it to a *different* >value every time it overwrites a descriptor. >How to achieve it? >since descriptors are written out in ring order, >simply maintain the current value internally (start value 1) and flip...

On Wed, Mar 01, 2017 at 03:02:29AM +0200, Michael S. Tsirkin wrote: > > > * Descriptor ring: > > > > > > Guest adds descriptors with unique index values and DESC_HW set in flags. > > > Host overwrites used descriptors with correct len, index, and DESC_HW > > > clear. Flags are always set/cleared last. > > > > May I know what's the index intended for? Back referencing a pkt buffer? > > Yes and generally identify which...

...> > > Driver writes descriptors with unique index values and DESC_DRIVER set in > > flags. > > Descriptors are written in a ring order: from start to end of ring, wrapping > > around to the beginning. > > Device writes used descriptors with correct len, index, and DESC_HW clear. > > Again descriptors are written in ring order. This might not be the same order > > of driver descriptors, and not all descriptors have to be written out. > > > > Driver and device are expected to maintain (internally) a wrap-around bit, > > starting at 0 and...