On Tue, Sep 29, 2015 at 04:53:28PM +0200, Igor Mammedov wrote: > setting gap to TRUE will make sparse DIMM > address auto allocation, leaving gaps between > a new DIMM address and preceeding existing DIMM. > > Signed-off-by: Igor Mammedov <imamm...@redhat.com> > --- > v2: > * make 'gap' boolean and just add 1 byte gap > when calculating new_addr for DIMM. > --- > hw/i386/pc.c | 3 ++- > hw/mem/pc-dimm.c | 15 +++++++++------ > hw/ppc/spapr.c | 2 +- > include/hw/mem/pc-dimm.h | 7 ++++--- > 4 files changed, 16 insertions(+), 11 deletions(-) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index 461c128..ef02736 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -1644,7 +1644,8 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev, > goto out; > } > > - pc_dimm_memory_plug(dev, &pcms->hotplug_memory, mr, align, &local_err); > + pc_dimm_memory_plug(dev, &pcms->hotplug_memory, mr, align, false, > + &local_err); > if (local_err) { > goto out; > } > diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c > index bb04862..6cc6ac3 100644 > --- a/hw/mem/pc-dimm.c > +++ b/hw/mem/pc-dimm.c > @@ -32,7 +32,8 @@ typedef struct pc_dimms_capacity { > } pc_dimms_capacity; > > void pc_dimm_memory_plug(DeviceState *dev, MemoryHotplugState *hpms, > - MemoryRegion *mr, uint64_t align, Error **errp) > + MemoryRegion *mr, uint64_t align, bool gap, > + Error **errp) > { > int slot; > MachineState *machine = MACHINE(qdev_get_machine()); > @@ -48,7 +49,7 @@ void pc_dimm_memory_plug(DeviceState *dev, > MemoryHotplugState *hpms, > > addr = pc_dimm_get_free_addr(hpms->base, > memory_region_size(&hpms->mr), > - !addr ? NULL : &addr, align, > + !addr ? NULL : &addr, align, gap, > memory_region_size(mr), &local_err); > if (local_err) { > goto out; > @@ -287,8 +288,8 @@ static int pc_dimm_built_list(Object *obj, void *opaque) > > uint64_t pc_dimm_get_free_addr(uint64_t address_space_start, > uint64_t address_space_size, > - uint64_t *hint, uint64_t align, uint64_t size, > - Error **errp) > + uint64_t *hint, uint64_t align, bool gap, > + uint64_t size, Error **errp) > { > GSList *list = NULL, *item; > uint64_t new_addr, ret = 0; > @@ -333,13 +334,15 @@ uint64_t pc_dimm_get_free_addr(uint64_t > address_space_start, > goto out; > } > > - if (ranges_overlap(dimm->addr, dimm_size, new_addr, size)) { > + if (ranges_overlap(dimm->addr, dimm_size, new_addr, > + size + (gap ? 1 : 0))) { > if (hint) { > DeviceState *d = DEVICE(dimm); > error_setg(errp, "address range conflicts with '%s'", d->id); > goto out; > } > - new_addr = QEMU_ALIGN_UP(dimm->addr + dimm_size, align); > + new_addr = QEMU_ALIGN_UP(dimm->addr + dimm_size + (gap ? 1 : 0), > + align);
This change of adding 1 byte gap will break PowerPC memory hotplug in its current form. Currently we divide hotpluggable memory region into chuncks of 256M and there is a DR connector object for each such chunk. The DR connector object maintains/controls the state transitions of that memory chunk as per PAPR specifications. Now after this 1 byte gap, we end up having a 64K alignment (default page size) for the DIMM address and end up having an address for which there is no DR connector object. I will have to revisit the parts of the code in PowerPC that creates DR connector objects and looks them up by address. Regards, Bharata.