On Thu, Aug 30, 2018 at 04:12:00PM -0600, Jon Derrick wrote: > Currently, a hotplug bridge will be given hpmemsize additional memory if > available, in order to satisfy any future hotplug allocation > requirements. > > These calculations don't consider the current memory size of the hotplug > bridge/slot, so hotplug bridges/slots which have downstream devices will > get their current allocation in addition to the hpmemsize value. > > This makes for possibly undesirable results with a mix of unoccupied and > occupied slots (ex, with hpmemsize=2M): > > 02:03.0 PCI bridge: <-- Occupied > Memory behind bridge: d6200000-d64fffff [size=3M] > 02:04.0 PCI bridge: <-- Unoccupied > Memory behind bridge: d6500000-d66fffff [size=2M] > > This change considers the current allocation size when using the > hpmemsize parameter to make the reservations predictable for the mix of > unoccupied and occupied slots: > > 02:03.0 PCI bridge: <-- Occupied > Memory behind bridge: d6200000-d63fffff [size=2M] > 02:04.0 PCI bridge: <-- Unoccupied > Memory behind bridge: d6400000-d65fffff [size=2M] > > The calculation for IO (hpiosize) should be similar, but platform > firmwares I've encountered (including QEMU) provide strict allocations > for IO and would not provide free IO resources for hotplug buses > in order to prove this calculation. > > Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx> Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
