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Subject[PATCH v2 1/7] vmw_balloon: fix inflation of 64-bit GFNs
Date
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@vger.kernel.org
Reviewed-by: Xavier Deguillard <xdeguillard@vmware.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
---
drivers/misc/vmw_balloon.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index efd733472a35..28e77ab1e136 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -450,7 +450,7 @@ static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn,

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(struct vmballoon *b, unsigned long pfn,

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 vmballoon *b, unsigned int num_pages,

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 vmballoon *b, unsigned int num_pages,
} else {
vmballoon_free_page(page, false);
}
- return -EIO;
+ return locked;
}

/* track allocated page */
--
2.17.0
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