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| author | Bharata B Rao <bharata@linux.vnet.ibm.com> | 2016-06-10 10:44:48 +0530 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2016-06-14 13:20:01 +1000 |
| commit | d0e5a8f2937de66778d94c20a8fc5cf43501fa04 (patch) | |
| tree | 4b5ff0e7a997bae3b58ef16f52c57faf49bdf50c /include | |
| parent | bc9ca5958d084222cdb233619dfc5046c81fb76d (diff) | |
| download | qemu-d0e5a8f2937de66778d94c20a8fc5cf43501fa04.tar.gz qemu-d0e5a8f2937de66778d94c20a8fc5cf43501fa04.tar.bz2 qemu-d0e5a8f2937de66778d94c20a8fc5cf43501fa04.zip | |
spapr: Ensure all LMBs are represented in ibm,dynamic-memory
Memory hotplug can fail for some combinations of RAM and maxmem when
DDW is enabled in the presence of devices like nec-usb-xhci. DDW depends
on maximum addressable memory returned by guest and this value is currently
being calculated wrongly by the guest kernel routine memory_hotplug_max().
While there is an attempt to fix the guest kernel, this patch works
around the problem within QEMU itself.
memory_hotplug_max() routine in the guest kernel arrives at max
addressable memory by multiplying lmb-size with the lmb-count obtained
from ibm,dynamic-memory property. There are two assumptions here:
- All LMBs are part of ibm,dynamic memory: This is not true for PowerKVM
where only hot-pluggable LMBs are present in this property.
- The memory area comprising of RAM and hotplug region is contiguous: This
needn't be true always for PowerKVM as there can be gap between
boot time RAM and hotplug region.
To work around this guest kernel bug, ensure that ibm,dynamic-memory
has information about all the LMBs (RMA, boot-time LMBs, future
hotpluggable LMBs, and dummy LMBs to cover the gap between RAM and
hotpluggable region).
RMA is represented separately by memory@0 node. Hence mark RMA LMBs
and also the LMBs for the gap b/n RAM and hotpluggable region as
reserved and as having no valid DRC so that these LMBs are not considered
by the guest.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'include')
| -rw-r--r-- | include/hw/ppc/spapr.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h index 971df3d0df..3ac85c07d7 100644 --- a/include/hw/ppc/spapr.h +++ b/include/hw/ppc/spapr.h @@ -620,9 +620,11 @@ int spapr_rng_populate_dt(void *fdt); #define SPAPR_DR_LMB_LIST_ENTRY_SIZE 6 /* - * This flag value defines the LMB as assigned in ibm,dynamic-memory - * property under ibm,dynamic-reconfiguration-memory node. + * Defines for flag value in ibm,dynamic-memory property under + * ibm,dynamic-reconfiguration-memory node. */ #define SPAPR_LMB_FLAGS_ASSIGNED 0x00000008 +#define SPAPR_LMB_FLAGS_DRC_INVALID 0x00000020 +#define SPAPR_LMB_FLAGS_RESERVED 0x00000080 #endif /* !defined (__HW_SPAPR_H__) */ |