xen: Add suspend/resume support for PV on HVM guests.

Suspend/resume requires few different things on HVM: the suspend
hypercall is different; we don't need to save/restore memory related
settings; except the shared info page and the callback mechanism.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 18 insertions, 6 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index b211a04c4b2c..127c95c8d15e 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1262,13 +1262,15 @@ static int init_hvm_pv_info(int *major, int *minor)
         return 0;
 }
 
-static void __init init_shared_info(void)
+void xen_hvm_init_shared_info(void)
 {
+        int cpu;
         struct xen_add_to_physmap xatp;
-        struct shared_info *shared_info_page;
+        static struct shared_info *shared_info_page = 0;
 
-        shared_info_page = (struct shared_info *)
-                extend_brk(PAGE_SIZE, PAGE_SIZE);
+        if (!shared_info_page)
+                shared_info_page = (struct shared_info *)
+                        extend_brk(PAGE_SIZE, PAGE_SIZE);
         xatp.domid = DOMID_SELF;
         xatp.idx = 0;
         xatp.space = XENMAPSPACE_shared_info;
@@ -1278,7 +1280,17 @@ static void __init init_shared_info(void)
 
         HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
 
-        per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
+        /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
+         * page, we use it in the event channel upcall and in some pvclock
+         * related functions. We don't need the vcpu_info placement
+         * optimizations because we don't use any pv_mmu or pv_irq op on
+         * HVM.
+         * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is
+         * online but xen_hvm_init_shared_info is run at resume time too and
+         * in that case multiple vcpus might be online. */
+        for_each_online_cpu(cpu) {
+                per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
+        }
 }
 
 static int __cpuinit xen_hvm_cpu_notify(struct notifier_block *self,
@@ -1308,7 +1320,7 @@ static void __init xen_hvm_guest_init(void)
         if (r < 0)
                 return;
 
-        init_shared_info();
+        xen_hvm_init_shared_info();
 
         if (xen_feature(XENFEAT_hvm_callback_vector))
                 xen_have_vector_callback = 1;