x86: lpc9: let firmware negotiate 'CPU hotplug with SMI' features

It will allow firmware to notify QEMU that firmware requires SMI
being triggered on CPU hot[un]plug, so that it would be able to account
for hotplugged CPU and relocate it to new SMM base and/or safely remove
CPU on unplug.

Using negotiated features, follow up patches will insert SMI upcall
into AML code, to make sure that firmware processes hotplug before
guest OS would attempt to use new CPU.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200923094650.1301166-2-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 50e8317342132de43532b1c16a95b9d8cbbe89f1..2c6194e57f383e6aa4a9fb28b4109548e767121d 100644 (file)
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -97,7 +97,9 @@
 #include "trace.h"
 #include CONFIG_DEVICES
 
-GlobalProperty pc_compat_5_1[] = {};
+GlobalProperty pc_compat_5_1[] = {
+    { "ICH9-LPC", "x-smi-cpu-hotplug", "off" },
+};
 const size_t pc_compat_5_1_len = G_N_ELEMENTS(pc_compat_5_1);
 
 GlobalProperty pc_compat_5_0[] = {

diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 3303d2eab6ca4c010652d18a75006c44eaa88be9..a54b3ec8bd87afa37fa6771d21634cf93594aed1 100644 (file)
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -373,6 +373,15 @@ static void smi_features_ok_callback(void *opaque)
         /* guest requests invalid features, leave @features_ok at zero */
         return;
     }
+    if (!(guest_features & BIT_ULL(ICH9_LPC_SMI_F_BROADCAST_BIT)) &&
+        guest_features & (BIT_ULL(ICH9_LPC_SMI_F_CPU_HOTPLUG_BIT) |
+                          BIT_ULL(ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT))) {
+        /*
+         * cpu hot-[un]plug with SMI requires SMI broadcast,
+         * leave @features_ok at zero
+         */
+        return;
+    }
 
     /* valid feature subset requested, lock it down, report success */
     lpc->smi_negotiated_features = guest_features;
@@ -747,6 +756,10 @@ static Property ich9_lpc_properties[] = {
     DEFINE_PROP_BOOL("noreboot", ICH9LPCState, pin_strap.spkr_hi, true),
     DEFINE_PROP_BIT64("x-smi-broadcast", ICH9LPCState, smi_host_features,
                       ICH9_LPC_SMI_F_BROADCAST_BIT, true),
+    DEFINE_PROP_BIT64("x-smi-cpu-hotplug", ICH9LPCState, smi_host_features,
+                      ICH9_LPC_SMI_F_CPU_HOTPLUG_BIT, true),
+    DEFINE_PROP_BIT64("x-smi-cpu-hotunplug", ICH9LPCState, smi_host_features,
+                      ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT, false),
     DEFINE_PROP_END_OF_LIST(),
 };
 

diff --git a/include/hw/i386/ich9.h b/include/hw/i386/ich9.h
index 48b442bc0b5cd7757adb12ac19a5d4d9a3d36b78..703d56036a753e6eb1681e8373604cf630934fb8 100644 (file)
--- a/include/hw/i386/ich9.h
+++ b/include/hw/i386/ich9.h
@@ -247,5 +247,7 @@ struct ICH9LPCState {
 
 /* bit positions used in fw_cfg SMI feature negotiation */
 #define ICH9_LPC_SMI_F_BROADCAST_BIT            0
+#define ICH9_LPC_SMI_F_CPU_HOTPLUG_BIT          1
+#define ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT       2
 
 #endif /* HW_ICH9_H */