[xen master] x86/HVM: more checking for XEN_DOMCTL_ioport_mapping

[patchbot@xxxxxxx]

commit fa61af950bb468c1f2ffe879991316e78c7921e0
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Jul 22 09:29:48 2026 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jul 22 09:29:48 2026 +0200

    x86/HVM: more checking for XEN_DOMCTL_ioport_mapping
    
    When adding ranges, only alter existing ones when there is an exact match.
    Don't accept ranges overlapping existing ones.
    
    When removing ranges, only remove a range if there's an exact match.
    Return an error when the range isn't found.
    
    Fixes: 192c4dabc344 ("domctl and p2m changes for PCI passthru")
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/domctl.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 3100f4283c..f26990208d 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -728,12 +728,14 @@ long arch_do_domctl(
                    "ioport_map:remove: %pd gport=%x mport=%x nr=%x\n",
                    d, fgp, fmp, np);
 
+            ret = -ENOENT;
             write_lock(&hvm->g2m_ioport_lock);
             list_for_each_entry(g2m_ioport, &hvm->g2m_ioport_list, list)
-                if ( g2m_ioport->mport == fmp )
+                if ( g2m_ioport->mport == fmp && g2m_ioport->np == np )
                 {
                     list_del(&g2m_ioport->list);
                     xfree(g2m_ioport);
+                    ret = 0;
                     break;
                 }
             write_unlock(&hvm->g2m_ioport_lock);
@@ -746,14 +748,21 @@ long arch_do_domctl(
 
             write_lock(&hvm->g2m_ioport_lock);
             list_for_each_entry(g2m_ioport, &hvm->g2m_ioport_list, list)
-                if (g2m_ioport->mport == fmp )
+            {
+                if ( g2m_ioport->mport == fmp && g2m_ioport->np == np )
                 {
                     g2m_ioport->gport = fgp;
-                    g2m_ioport->np = np;
                     found = 1;
                     break;
                 }
-            if ( !found )
+                if ( fmp + np >= g2m_ioport->mport &&
+                     g2m_ioport->mport + g2m_ioport->np >= fmp )
+                {
+                    ret = -EBUSY;
+                    break;
+                }
+            }
+            if ( !found && !ret )
             {
                 g2m_ioport = xmalloc(struct g2m_ioport);
                 if ( !g2m_ioport )
--
generated by git-patchbot for /home/xen/git/xen.git#master