Commits
Dexuan Cui committed e5d2f910cfe
PCI: hv: Add a paravirtual backchannel in software Windows SR-IOV provides a backchannel mechanism in software for communication between a VF driver and a PF driver. These "configuration blocks" are similar in concept to PCI configuration space, but instead of doing reads and writes in 32-bit chunks through a very slow path, packets of up to 128 bytes can be sent or received asynchronously. Nearly every SR-IOV device contains just such a communications channel in hardware, so using this one in software is usually optional. Using the software channel, however, allows driver implementers to leverage software tools that fuzz the communications channel looking for vulnerabilities. The usage model for these packets puts the responsibility for reading or writing on the VF driver. The VF driver sends a read or a write packet, indicating which "block" is being referred to by number. If the PF driver wishes to initiate communication, it can "invalidate" one or more of the first 64 blocks. This invalidation is delivered via a callback supplied by the VF driver by this driver. No protocol is implied, except that supplied by the PF and VF drivers. Signed-off-by: Jake Oshins <jakeo@microsoft.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>