docs: clarify that spec-ctrl is only needed for Spectre v2

The docs currently say that the spec-ctrl feature is needed for both
Spectre variants, but it is only used to address Spectre v2. Also
remove the note about retpolines. The guest OS is usually treated
as a blackbox from host mgmt pov, so it won't have knowledge about
use of retpolines and thus should unconditionally expose spec-ctrl,
allowing the guest to decide whether to use it or not.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20190307121838.6345-2-berrange@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

diff --git a/docs/qemu-cpu-models.texi b/docs/qemu-cpu-models.texi
index 1b725841616b0e5f74243822074141b99ceb4b5e..0ce528806dc38dddc430a892251c3e57fcc1ea81 100644 (file)
--- a/docs/qemu-cpu-models.texi
+++ b/docs/qemu-cpu-models.texi
@@ -158,8 +158,7 @@ support this feature.
 
 @item @code{spec-ctrl}
 
-Required to enable the Spectre (CVE-2017-5753 and CVE-2017-5715) fix,
-in cases where retpolines are not sufficient.
+Required to enable the Spectre v2 (CVE-2017-5715) fix.
 
 Included by default in Intel CPU models with -IBRS suffix.
 
@@ -249,8 +248,7 @@ included if using "Host passthrough" or "Host model".
 
 @item @code{ibpb}
 
-Required to enable the Spectre (CVE-2017-5753 and CVE-2017-5715) fix,
-in cases where retpolines are not sufficient.
+Required to enable the Spectre v2 (CVE-2017-5715) fix.
 
 Included by default in AMD CPU models with -IBPB suffix.