x86/xen: Split HVM vector callback setup and interrupt gate allocation

As a preparatory change for making alloc_intr_gate() __init split
xen_callback_vector() into callback vector setup via hypercall
(xen_setup_callback_vector()) and interrupt gate allocation
(xen_alloc_callback_vector()).

xen_setup_callback_vector() is being called twice: on init and upon
system resume from xen_hvm_post_suspend(). alloc_intr_gate() only
needs to be called once.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200428093824.1451532-2-vkuznets@redhat.com

diff --git a/arch/x86/xen/suspend_hvm.c b/arch/x86/xen/suspend_hvm.c
index e666b614cf6d2cb80ac956b0913baae65e50d30b..5152afe16876695a6abddc557353e9b7f2d13870 100644 (file)
--- a/arch/x86/xen/suspend_hvm.c
+++ b/arch/x86/xen/suspend_hvm.c
@@ -13,6 +13,6 @@ void xen_hvm_post_suspend(int suspend_cancelled)
                xen_hvm_init_shared_info();
                xen_vcpu_restore();
        }
-       xen_callback_vector();
+       xen_setup_callback_vector();
        xen_unplug_emulated_devices();
 }

diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 45a441c33d6dc4213ade35508bf0891ad01600f2..1cc1568bfe048b0d38020256d2289450e1eaa0e8 100644 (file)
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -55,7 +55,7 @@ void xen_enable_sysenter(void);
 void xen_enable_syscall(void);
 void xen_vcpu_restore(void);
 
-void xen_callback_vector(void);
+void xen_setup_callback_vector(void);
 void xen_hvm_init_shared_info(void);
 void xen_unplug_emulated_devices(void);
 

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 3a791c8485d090cd202f784b58e1ae5bde2e99db..eb35c3cda9a6fd38f75004f141c2ce54f4945aeb 100644 (file)
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -1639,26 +1639,30 @@ EXPORT_SYMBOL_GPL(xen_set_callback_via);
 /* Vector callbacks are better than PCI interrupts to receive event
  * channel notifications because we can receive vector callbacks on any
  * vcpu and we don't need PCI support or APIC interactions. */
-void xen_callback_vector(void)
+void xen_setup_callback_vector(void)
 {
-       int rc;
        uint64_t callback_via;
 
        if (xen_have_vector_callback) {
                callback_via = HVM_CALLBACK_VECTOR(HYPERVISOR_CALLBACK_VECTOR);
-               rc = xen_set_callback_via(callback_via);
-               if (rc) {
+               if (xen_set_callback_via(callback_via)) {
                        pr_err("Request for Xen HVM callback vector failed\n");
                        xen_have_vector_callback = 0;
-                       return;
                }
-               pr_info_once("Xen HVM callback vector for event delivery is enabled\n");
-               alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
-                               xen_hvm_callback_vector);
        }
 }
+
+static __init void xen_alloc_callback_vector(void)
+{
+       if (!xen_have_vector_callback)
+               return;
+
+       pr_info("Xen HVM callback vector for event delivery is enabled\n");
+       alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, xen_hvm_callback_vector);
+}
 #else
-void xen_callback_vector(void) {}
+void xen_setup_callback_vector(void) {}
+static inline void xen_alloc_callback_vector(void) {}
 #endif
 
 #undef MODULE_PARAM_PREFIX
@@ -1692,8 +1696,10 @@ void __init xen_init_IRQ(void)
                if (xen_initial_domain())
                        pci_xen_initial_domain();
        }
-       if (xen_feature(XENFEAT_hvm_callback_vector))
-               xen_callback_vector();
+       if (xen_feature(XENFEAT_hvm_callback_vector)) {
+               xen_setup_callback_vector();
+               xen_alloc_callback_vector();
+       }
 
        if (xen_hvm_domain()) {
                native_init_IRQ();