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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Xavier Deguillard <xdeguillard@vmware.com>,
        Nadav Amit <namit@vmware.com>
Subject: [PATCH 4.4 17/47] vmw_balloon: fix inflation of 64-bit GFNs
Date:   Fri,  7 Sep 2018 23:10:13 +0200
Message-Id: <20180907210906.264651444@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Nadav Amit <namit@vmware.com>

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@vger.kernel.org
Reviewed-by: Xavier Deguillard <xdeguillard@vmware.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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 */