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[PATCH v1 1/2] domctl: Handle XEN_DOMCTL_getpageframeinfo3 without the domctl lock


  • To: xen-devel@xxxxxxxxxxxxxxxxxxxx
  • From: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
  • Date: Tue, 9 Jun 2026 16:15:27 +0100
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  • Cc: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Teddy Astie <teddy.astie@xxxxxxxxxx>, Anthony PERARD <anthony.perard@xxxxxxxxxx>, Michal Orzel <michal.orzel@xxxxxxx>, Julien Grall <julien@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, "Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>
  • Delivery-date: Tue, 09 Jun 2026 15:15:41 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

It does not have side effects and is protected from concurrent changes
by the P2M read lock therefore skip taking the domctl lock.

Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
---
 xen/arch/x86/domctl.c | 4 ++++
 xen/common/domctl.c   | 1 +
 2 files changed, 5 insertions(+)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 83bf51e498df..0e9a2532887e 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -301,6 +301,10 @@ long arch_do_domctl(
         /* Games to allow this code block to handle a compat guest. */
         void __user *guest_handle = domctl->u.getpageframeinfo3.array.p;
 
+        ret = xsm_domctl(XSM_OTHER, d, domctl);
+        if ( ret )
+            break;
+
         if ( unlikely(num > 1024) ||
              unlikely(num != domctl->u.getpageframeinfo3.num) )
         {
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 3efa5b9d55b9..35144d95b808 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -555,6 +555,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
u_domctl)
     case XEN_DOMCTL_gsi_permission:
     case XEN_DOMCTL_bind_pt_irq:
     case XEN_DOMCTL_unbind_pt_irq:
+    case XEN_DOMCTL_getpageframeinfo3:
         ret = arch_do_domctl(op, d, u_domctl);
         goto domctl_out_unlock_domonly;
 
-- 
2.53.0




 


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