[xen master] x86: don't allow Dom0 access to port 92

[patchbot@xxxxxxx]

commit 9e2c146c38a74e6ced610599224ce216cae13874
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Nov 2 10:44:11 2023 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Nov 2 10:44:11 2023 +0100

    x86: don't allow Dom0 access to port 92
    
    Somewhat like port CF9 this may have a bit controlling the CPU's INIT#
    signal, and it also may have a bit involved in the driving of A20M#.
    Neither of these - just like CF9 - we want to allow Dom0 to drive.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/dom0_build.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 5dc5872e38..c31afc734f 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -488,6 +488,10 @@ int __init dom0_setup_permissions(struct domain *d)
     rc |= ioports_deny_access(d, 0x40, 0x43);
     /* PIT Channel 2 / PC Speaker Control. */
     rc |= ioports_deny_access(d, 0x61, 0x61);
+
+    /* INIT# and alternative A20M# control. */
+    rc |= ioports_deny_access(d, 0x92, 0x92);
+
     /* ACPI PM Timer. */
     if ( pmtmr_ioport )
         rc |= ioports_deny_access(d, pmtmr_ioport, pmtmr_ioport + 3);
--
generated by git-patchbot for /home/xen/git/xen.git#master