From c2a38a627251956e80826496e958b3c80a24837e Mon Sep 17 00:00:00 2001
From: Damien Zammit <damien@zamaudio.com>
Date: Tue, 24 Aug 2021 13:58:00 +0200
Subject: rumpdisk: Ensure physical allocation of memory for DMA reads

* rumpdisk/block-rump.c (rumpdisk_device_read): Memset the buffer
after allocating it.
---
 rumpdisk/block-rump.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'rumpdisk')

diff --git a/rumpdisk/block-rump.c b/rumpdisk/block-rump.c
index 224e4e5b..5477d886 100644
--- a/rumpdisk/block-rump.c
+++ b/rumpdisk/block-rump.c
@@ -326,6 +326,9 @@ rumpdisk_device_read (void *d, mach_port_t reply_port,
   if (ret != KERN_SUCCESS)
     return ENOMEM;
 
+  /* Ensure physical allocation.  */
+  memset (buf, 0, npages * pagesize);
+
   err = rump_sys_pread (bd->rump_fd, (void *)buf, (size_t)count, (off_t)bn * bd->block_size);
   if (err < 0)
     {
-- 
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