x86/xen: Add support for HVMOP_set_evtchn_upcall_vector

Implement support for the HVMOP_set_evtchn_upcall_vector hypercall in
order to set the per-vCPU event channel vector callback on Linux and
use it in preference of HVM_PARAM_CALLBACK_IRQ.

If the per-VCPU vector setup is successful on BSP, use this method
for the APs. If not, fallback to the global vector-type callback.

Also register callback_irq at per-vCPU event channel setup to trick
toolstack to think the domain is enlightened.

Suggested-by: "Roger Pau Monné" <roger.pau@citrix.com>
Signed-off-by: Jane Malalane <jane.malalane@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20220729070416.23306-1-jane.malalane@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/arch/x86/xen/suspend_hvm.c b/arch/x86/xen/suspend_hvm.c
index 9d548b0c772f..0c4f7554b7cc 100644
--- a/arch/x86/xen/suspend_hvm.c
+++ b/arch/x86/xen/suspend_hvm.c
@@ -5,6 +5,7 @@
 #include <xen/hvm.h>
 #include <xen/features.h>
 #include <xen/interface/features.h>
+#include <xen/events.h>
 
 #include "xen-ops.h"
 
@@ -14,6 +15,13 @@ void xen_hvm_post_suspend(int suspend_cancelled)
 		xen_hvm_init_shared_info();
 		xen_vcpu_restore();
 	}
-	xen_setup_callback_vector();
+	if (xen_percpu_upcall) {
+		unsigned int cpu;
+
+		for_each_online_cpu(cpu)
+			BUG_ON(xen_set_upcall_vector(cpu));
+	} else {
+		xen_setup_callback_vector();
+	}
 	xen_unplug_emulated_devices();
 }