commit 93eac7b8f44738f7d2f4ba4460d67b04af5b0b99
author Nicholas Piggin <npiggin@gmail.com> Mon Jul 22 16:17:52 2019 +1000
committer David Gibson <david@gibson.dropbear.id.au> Wed Aug 21 17:17:39 2019 +1000
tree 9044565ac3d6082ac008cafa39761d394e9242d6
parent c508bd12f65e14f82eb62e462bcb64898d8806a6

spapr: Implement ibm,suspend-me

This has been useful to modify and test the Linux pseries suspend
code but it requires modification to the guest to call it (due to
being gated by other unimplemented features). It is not otherwise
used by Linux yet, but work is slowly progressing there.

This allows a (lightly modified) guest kernel to suspend with
`echo mem > /sys/power/state` and be resumed with system_wakeup
monitor command.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20190722061752.22114-2-npiggin@gmail.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

hw/ppc/spapr.c

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 56b3357..51e1cb0 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -3083,6 +3083,13 @@
 
     qemu_register_boot_set(spapr_boot_set, spapr);
 
+    /*
+     * Nothing needs to be done to resume a suspended guest because
+     * suspending does not change the machine state, so no need for
+     * a ->wakeup method.
+     */
+    qemu_register_wakeup_support();
+
     if (kvm_enabled()) {
         /* to stop and start vmclock */
         qemu_add_vm_change_state_handler(cpu_ppc_clock_vm_state_change,

hw/ppc/spapr_rtas.c

diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index d3f9a69..526b489 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -217,6 +217,36 @@
     qemu_cpu_kick(cs);
 }
 
+static void rtas_ibm_suspend_me(PowerPCCPU *cpu, SpaprMachineState *spapr,
+                           uint32_t token, uint32_t nargs,
+                           target_ulong args,
+                           uint32_t nret, target_ulong rets)
+{
+    CPUState *cs;
+
+    if (nargs != 0 || nret != 1) {
+        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+        return;
+    }
+
+    CPU_FOREACH(cs) {
+        PowerPCCPU *c = POWERPC_CPU(cs);
+        CPUPPCState *e = &c->env;
+        if (c == cpu) {
+            continue;
+        }
+
+        /* See h_join */
+        if (!cs->halted || (e->msr & (1ULL << MSR_EE))) {
+            rtas_st(rets, 0, H_MULTI_THREADS_ACTIVE);
+            return;
+        }
+    }
+
+    qemu_system_suspend_request();
+    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+}
+
 static inline int sysparm_st(target_ulong addr, target_ulong len,
                              const void *val, uint16_t vallen)
 {
@@ -484,6 +514,8 @@
                         rtas_query_cpu_stopped_state);
     spapr_rtas_register(RTAS_START_CPU, "start-cpu", rtas_start_cpu);
     spapr_rtas_register(RTAS_STOP_SELF, "stop-self", rtas_stop_self);
+    spapr_rtas_register(RTAS_IBM_SUSPEND_ME, "ibm,suspend-me",
+                        rtas_ibm_suspend_me);
     spapr_rtas_register(RTAS_IBM_GET_SYSTEM_PARAMETER,
                         "ibm,get-system-parameter",
                         rtas_ibm_get_system_parameter);

include/hw/ppc/spapr.h

diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index c79bc6a..fa7c380 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -642,8 +642,9 @@
 #define RTAS_IBM_CREATE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x27)
 #define RTAS_IBM_REMOVE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x28)
 #define RTAS_IBM_RESET_PE_DMA_WINDOW            (RTAS_TOKEN_BASE + 0x29)
+#define RTAS_IBM_SUSPEND_ME                     (RTAS_TOKEN_BASE + 0x2A)
 
-#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2A)
+#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2B)
 
 /* RTAS ibm,get-system-parameter token values */
 #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20