When Dom0 finalizes its suspend procedure the suspend of Xen is
triggered by calling system_suspend(). Dom0 finalizes the suspend from
its boot core (VCPU#0), which could be mapped to any physical CPU,
i.e. the system_suspend() function could be executed by any physical
CPU. Since Xen suspend procedure has to be run by the boot CPU
(non-boot CPUs will be disabled at some point in suspend procedure),
system_suspend() execution has to continue on CPU#0.
When the system_suspend() returns 0, it means that the system was
suspended and it is coming out of the resume procedure. Regardless
of the system_suspend() return value, after this function returns
Xen is fully functional, and its state, including all devices and data
structures, matches the state prior to calling system_suspend().
The status is returned by system_suspend() for debugging/logging
purposes and function prototype compatibility.
Signed-off-by: Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>
Signed-off-by: Saeed Nowshadi <saeed.nowshadi@xxxxxxxxxx>
---
xen/arch/arm/suspend.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/xen/arch/arm/suspend.c b/xen/arch/arm/suspend.c
index f2338e41db..21b45f8248 100644
--- a/xen/arch/arm/suspend.c
+++ b/xen/arch/arm/suspend.c
@@ -112,11 +112,20 @@ static void vcpu_suspend(register_t epoint, register_t
cid)
_arch_set_info_guest(v, &ctxt);
}
+/* Xen suspend. Note: data is not used (suspend is the suspend to RAM) */
+static long system_suspend(void *data)
+{
+ BUG_ON(system_state != SYS_STATE_active);
+
+ return -ENOSYS;
+}
+
int32_t domain_suspend(register_t epoint, register_t cid)
{
struct vcpu *v;
struct domain *d = current->domain;
bool is_thumb = epoint & 1;
+ int status;
dprintk(XENLOG_DEBUG,
"Dom%d suspend: epoint=0x%"PRIregister", cid=0x%"PRIregister"\n",
@@ -156,6 +165,31 @@ int32_t domain_suspend(register_t epoint, register_t cid)
*/
vcpu_block_unless_event_pending(current);
+ /* If this was dom0 the whole system should suspend: trigger Xen suspend */
+ if ( is_hardware_domain(d) )
+ {
+ /*
+ * system_suspend should be called when Dom0 finalizes the suspend
+ * procedure from its boot core (VCPU#0). However, Dom0's VCPU#0 could
+ * be mapped to any PCPU (this function could be executed by any PCPU).
+ * The suspend procedure has to be finalized by the PCPU#0 (non-boot
+ * PCPUs will be disabled during the suspend).
+ */
+ status = continue_hypercall_on_cpu(0, system_suspend, NULL);
+ /*
+ * If an error happened, there is nothing that needs to be done here
+ * because the system_suspend always returns in fully functional state
+ * no matter what the outcome of suspend procedure is. If the system
+ * suspended successfully the function will return 0 after the resume.
+ * Otherwise, if an error is returned it means Xen did not suspended,
+ * but it is still in the same state as if the system_suspend was never
+ * called. We dump a debug message in case of an error for debugging/
+ * logging purpose.
+ */
+ if ( status )
+ dprintk(XENLOG_ERR, "Failed to suspend, errno=%d\n", status);
+ }
