Commit 647965a2 authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by Greg Kroah-Hartman
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Drivers: hv: balloon: Permit Linux to specify hot-add alignment requirements 



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: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 39d79164

drivers/hv/hv_balloon.c

+15 −2
Original line number Diff line number Diff line
@@ -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;
@@ -774,7 +781,7 @@ 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;
@@ -1366,6 +1373,12 @@ static int balloon_probe(struct hv_device *dev, 
	cap_msg.caps.cap_bits.balloon = 1;

	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

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