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.
Reported-by: Jann Horn <ja...@google.com>
Signed-off-by: George Dunlap <george.dun...@citrix.com>
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
v2:
- add in Kconfig from advisory, ported over c/s d23d792478d
---
SUPPORT.md | 9 +--------
xen/arch/x86/Kconfig | 7 +++++--
2 files changed, 6 insertions(+), 10 deletions(-)
diff --git a/SUPPORT.md b/SUPPORT.md
index d0d4fc6f4f..a29680e04c 100644
--- a/SUPPORT.md
+++ b/SUPPORT.md
@@ -86,14 +86,7 @@ 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
diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index e55e029b79..9b164db641 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -55,7 +55,7 @@ config PV
config PV32
bool "Support for 32bit PV guests"
depends on PV
- default y
+ default PV_SHIM
select COMPAT
---help---
The 32bit PV ABI uses Ring1, an area of the x86 architecture which
@@ -67,7 +67,10 @@ config PV32
reduction, or performance reasons. Backwards compatibility can be
provided via the PV Shim mechanism.
- If unsure, say Y.
+ Note that outside of PV Shim, 32-bit PV guests are not security
+ supported anymore.
+
+ If unsure, use the default setting.
config PV_LINEAR_PT
bool "Support for PV linear pagetables"
--
2.30.2
