blob: 512e69cc17f72bb3406b765001ac1277fe76ac15 [file] [log] [blame]
From: Bharata B Rao <bharata@linux.vnet.ibm.com>
Date: Thu, 12 May 2016 19:04:15 +0530
Subject: powerpc/numa: Fix multiple bugs in memory_hotplug_max()
commit 45b64ee64970dee9392229302efe1d1567e8d304 upstream.
memory_hotplug_max() uses hot_add_drconf_memory_max() to get maxmimum
addressable memory by referring to ibm,dyanamic-memory property. There
are three problems with the current approach:
1 hot_add_drconf_memory_max() assumes that ibm,dynamic-memory includes
all the LMBs of the guest, but that is not true for PowerKVM which
populates only DR LMBs (LMBs that can be hotplugged/removed) in that
property.
2 hot_add_drconf_memory_max() multiplies lmb-size with lmb-count to arrive
at the max possible address. Since ibm,dynamic-memory doesn't include
RMA LMBs, the address thus obtained will be less than the actual max
address. For example, if max possible memory size is 32G, with lmb-size
of 256MB there can be 127 LMBs in ibm,dynamic-memory (1 LMB for RMA
which won't be present here). hot_add_drconf_memory_max() would then
return the max addressable memory as 127 * 256MB = 31.75GB, the max
address should have been 32G which is what ibm,lrdr-capacity shows.
3 In PowerKVM, there can be a gap between the end of boot time RAM and
beginning of hotplug RAM area. So just multiplying lmb-count with
lmb-size will not provide the correct max possible address for PowerKVM.
This patch fixes 1 by using ibm,lrdr-capacity property to return the max
addressable memory whenever the property is present. Then it fixes 2 & 3
by fetching the address of the last LMB in ibm,dynamic-memory property.
Fixes: cd34206e949b ("powerpc: Add memory_hotplug_max()")
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/powerpc/mm/numa.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1275,17 +1275,33 @@ int hot_add_scn_to_nid(unsigned long scn
static u64 hot_add_drconf_memory_max(void)
{
struct device_node *memory = NULL;
+ struct device_node *dn = NULL;
unsigned int drconf_cell_cnt = 0;
u64 lmb_size = 0;
const u32 *dm = 0;
+ const __be64 *lrdr = NULL;
+ struct of_drconf_cell drmem;
+
+ dn = of_find_node_by_path("/rtas");
+ if (dn) {
+ lrdr = of_get_property(dn, "ibm,lrdr-capacity", NULL);
+ of_node_put(dn);
+ if (lrdr)
+ return be64_to_cpup(lrdr);
+ }
memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
if (memory) {
drconf_cell_cnt = of_get_drconf_memory(memory, &dm);
lmb_size = of_get_lmb_size(memory);
+
+ /* Advance to the last cell, each cell has 6 32 bit integers */
+ dm += (drconf_cell_cnt - 1) * 6;
+ read_drconf_cell(&drmem, &dm);
of_node_put(memory);
+ return drmem.base_addr + lmb_size;
}
- return lmb_size * drconf_cell_cnt;
+ return 0;
}
/*