[PATCH 4.18 069/145] vmw_balloon: fix inflation of 64-bit GFNs

From: Greg Kroah-Hartman
Date: Fri Sep 07 2018 - 17:18:09 EST


4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Nadav Amit <namit@xxxxxxxxxx>

commit 09755690c6b7c1eabdc4651eb3b276f8feb1e447 upstream.

When balloon batching is not supported by the hypervisor, the guest
frame number (GFN) must fit in 32-bit. However, due to a bug, this check
was mistakenly ignored. In practice, when total RAM is greater than
16TB, the balloon does not work currently, making this bug unlikely to
happen.

Fixes: ef0f8f112984 ("VMware balloon: partially inline vmballoon_reserve_page.")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Xavier Deguillard <xdeguillard@xxxxxxxxxx>
Signed-off-by: Nadav Amit <namit@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/misc/vmw_balloon.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -450,7 +450,7 @@ static int vmballoon_send_lock_page(stru

pfn32 = (u32)pfn;
if (pfn32 != pfn)
- return -1;
+ return -EINVAL;

STATS_INC(b->stats.lock[false]);

@@ -460,7 +460,7 @@ static int vmballoon_send_lock_page(stru

pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
STATS_INC(b->stats.lock_fail[false]);
- return 1;
+ return -EIO;
}

static int vmballoon_send_batched_lock(struct vmballoon *b,
@@ -597,11 +597,12 @@ static int vmballoon_lock_page(struct vm

locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status,
target);
- if (locked > 0) {
+ if (locked) {
STATS_INC(b->stats.refused_alloc[false]);

- if (hv_status == VMW_BALLOON_ERROR_RESET ||
- hv_status == VMW_BALLOON_ERROR_PPN_NOTNEEDED) {
+ if (locked == -EIO &&
+ (hv_status == VMW_BALLOON_ERROR_RESET ||
+ hv_status == VMW_BALLOON_ERROR_PPN_NOTNEEDED)) {
vmballoon_free_page(page, false);
return -EIO;
}
@@ -617,7 +618,7 @@ static int vmballoon_lock_page(struct vm
} else {
vmballoon_free_page(page, false);
}
- return -EIO;
+ return locked;
}

/* track allocated page */