[PATCH 1/1] Drivers: hv: balloon: Permit Linux to specify hot-add alignment requirements
From: K. Y. Srinivasan
Date: Fri Mar 29 2013 - 10:05:30 EST
Some Windows hosts permit the guest to specify memory hot-add alignment
requirements (if any). Linux currently requires a 128MB alignment on memory
segments that can be hot-added. Specify this alignment requirement to the
host.
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/hv/hv_balloon.c | 17 +++++++++++++++--
1 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 4cc1d10..e598c67 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -117,7 +117,14 @@ union dm_caps {
struct {
__u64 balloon:1;
__u64 hot_add:1;
- __u64 reservedz:62;
+ /*
+ * To support guests that may have alignment
+ * limitations on hot-add, the guest can specify
+ * its alignment requirements; a value of n
+ * represents an alignment of 2^n in mega bytes.
+ */
+ __u64 hot_add_alignment:4;
+ __u64 reservedz:58;
} cap_bits;
__u64 caps;
} __packed;
@@ -784,7 +791,7 @@ static unsigned long process_hot_add(unsigned long pg_start,
* If the host has specified a hot-add range; deal with it first.
*/
- if ((rg_size != 0) && (!dm_device.host_specified_ha_region)) {
+ if (rg_size != 0) {
ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL);
if (!ha_region)
return 0;
@@ -1410,6 +1417,12 @@ static int balloon_probe(struct hv_device *dev,
cap_msg.caps.cap_bits.hot_add = 1;
/*
+ * Specify our alignment requirements as it relates
+ * memory hot-add. Specify 128MB alignment.
+ */
+ cap_msg.caps.cap_bits.hot_add_alignment = 7;
+
+ /*
* Currently the host does not use these
* values and we set them to what is done in the
* Windows driver.
--
1.7.4.1
--
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