File xsa370-2.patch of Package xen.19587

From: George Dunlap <george.dunlap@citrix.com>
Subject: SUPPORT.md: Un-shimmed 32-bit PV guests are no longer supported

The support status of 32-bit guests doesn't seem particularly useful.

With it changed to fully unsupported outside of PV-shim, adjust the PV32
Kconfig default accordingly.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---

NB this patch should be considered a proposal to the community.  It
will not become effective until three weeks after the XSA-370 embargo
lifts, and only if there are no objections raised before that point.

TBD: Should we also default opt_pv32 to false when not running in shim
     mode?

The (forward) dependency on PV_SHIM isn't very useful especially when
configuring from scratch - we may want to re-order items down the road,
such that the prompt for PV_SHIM occurs ahead of that for PV32. Yet then
this conflicts with PV_SHIM also depending on GUEST.

v3:
- Add Kconfig adjustment.

v2:
- Port over changes in patch 1

Index: xen-4.11.4-testing/SUPPORT.md
===================================================================
--- xen-4.11.4-testing.orig/SUPPORT.md
+++ xen-4.11.4-testing/SUPPORT.md
@@ -75,14 +75,7 @@ No hardware requirements
 
     Status, x86_64: Supported
     Status, x86_32, shim: Supported
-    Status, x86_32, without shim: Supported, with caveats
-
-Due to architectural limitations,
-32-bit PV guests must be assumed to be able to read arbitrary host memory
-using speculative execution attacks.
-Advisories will continue to be issued
-for new vulnerabilities related to un-shimmed 32-bit PV guests
-enabling denial-of-service attacks or privilege escalation attacks.
+    Status, x86_32, without shim: Supported, not security supported
 
 ### x86/HVM
 
Index: xen-4.11.4-testing/xen/arch/x86/Kconfig
===================================================================
--- xen-4.11.4-testing.orig/xen/arch/x86/Kconfig
+++ xen-4.11.4-testing/xen/arch/x86/Kconfig
@@ -117,6 +117,9 @@ config TBOOT
 	  Allows support for Trusted Boot using the Intel(R) Trusted Execution
 	  Technology (TXT)
 
+	  Note that outside of PV Shim, 32-bit PV guests are not security
+	  supported anymore.
+
 	  If unsure, say Y.
 
 config XEN_GUEST