On 10/18/2024 4:58 AM, Naman Jain wrote: > Channels offers are requested during vmbus initialization and resume > from hibernation. Add support to wait for all channel offers to be > delivered and processed before returning from vmbus_request_offers. > This is to support user mode (VTL0) in OpenHCL (A Linux based > paravisor for Confidential VMs) to ensure that all channel offers > are present when init begins in VTL0, and it knows which channels > the host has offered and which it has not. > > This is in analogy to a PCI bus not returning from probe until it has > scanned all devices on the bus. > > Without this, user mode can race with vmbus initialization and miss > channel offers. User mode has no way to work around this other than > sleeping for a while, since there is no way to know when vmbus has > finished processing offers. > > With this added functionality, remove earlier logic which keeps track > of count of offered channels post resume from hibernation. Once all > offers delivered message is received, no further offers are going to > be received. Consequently, logic to prevent suspend from happening > after previous resume had missing offers, is also removed. > > Co-developed-by: John Starks <jostarks@xxxxxxxxxxxxx> > Signed-off-by: John Starks <jostarks@xxxxxxxxxxxxx> > Signed-off-by: Naman Jain <namjain@xxxxxxxxxxxxxxxxxxx> > --- > drivers/hv/channel_mgmt.c | 38 +++++++++++++++++++++++--------------- > drivers/hv/connection.c | 4 ++-- > drivers/hv/hyperv_vmbus.h | 14 +++----------- > drivers/hv/vmbus_drv.c | 16 ---------------- > 4 files changed, 28 insertions(+), 44 deletions(-) Looks good to me. Reviewed-by: Easwar Hariharan <eahariha@xxxxxxxxxxxxxxxxxxx>
