[PATCH 3/3] docs/secure-coding-practices: Describe null-co/zeroes-co block drivers

[Philippe Mathieu-Daudé]

Document that security reports must not use the 'null-co' block
driver, as it leaves memory uninitialized on purposed (this is
a performance feature).
Reports must be send using the 'zeroes-co' driver.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 docs/devel/secure-coding-practices.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/devel/secure-coding-practices.rst 
b/docs/devel/secure-coding-practices.rst
index cbfc8af67e6..64d61085804 100644
--- a/docs/devel/secure-coding-practices.rst
+++ b/docs/devel/secure-coding-practices.rst
@@ -104,3 +104,10 @@ structures and only process the local copy.  This prevents
 time-of-check-to-time-of-use (TOCTOU) race conditions that could cause QEMU to
 crash when a vCPU thread modifies guest RAM while device emulation is
 processing it.
+
+Use of null-co / zeroes-co block drivers
+----------------------------------------
+
+When reporting security issues, the null-co block driver must not be used,
+as it is designed for performance and its read accesses are not initialized.
+The zeroes-co block driver must be used instead.
-- 
2.26.2