[RFC PATCH] hw/arm/virt: use sbsa-ec for reboot and poweroff in secure mode

[Maxim Uvarov <maxim.uvarov@linaro.org>]

If we're emulating EL3 then the EL3 guest firmware is responsible for
providing the PSCI ABI, including reboot, core power down, etc.
sbsa-ref machine has an embedded controller to do reboot, poweroff. Machine
virt,secure=on can reuse this code to do reboot inside ATF.

Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
---
 Hello,

 This patch implements reboot for the secure machine inside ATF firmware. I.e. current qemu
 patch should be used with [1] ATF patch. It looks like that Embedded Controller qemu
 driver (sbsa-ec) can be common and widely used for other emulated machines. While if
 there are plans to extend sbsa-ec then we might find some other solution.

 So for the long term it looks like machine virt was used as an initial playground for secure
 firmware.  While the original intent was a runner for kvm guests. Relation between kvm guest
 and firmware  is not very clear now. If everyone agree it might be good solution to move secure
 firmware things from virt machine to bsa-ref and make this machine reference for secure boot,
 firmware updates  etc.

 [1] https://github.com/muvarov/arm-trusted-firmware/commit/6d3339a0081f6f2b45d99bd7e1b67bcbce8f4e0e

 Best regards,
 Maxim.

 hw/arm/virt.c         | 9 +++++++++
 include/hw/arm/virt.h | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index e465a988d6..6b77912f02 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -152,6 +152,7 @@ static const MemMapEntry base_memmap[] = {
     [VIRT_ACPI_GED] =           { 0x09080000, ACPI_GED_EVT_SEL_LEN },
     [VIRT_NVDIMM_ACPI] =        { 0x09090000, NVDIMM_ACPI_IO_LEN},
     [VIRT_PVTIME] =             { 0x090a0000, 0x00010000 },
+    [VIRT_EC] =                 { 0x090c0000, 0x00001000 },
     [VIRT_MMIO] =               { 0x0a000000, 0x00000200 },
     /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size */
     [VIRT_PLATFORM_BUS] =       { 0x0c000000, 0x02000000 },
@@ -1729,6 +1730,13 @@ static void virt_cpu_post_init(VirtMachineState *vms, int max_cpus,
     }
 }
 
+static void init_ec_controller(VirtMachineState *vms)
+{
+    vms->ec = qdev_new("sbsa-ec");
+
+    sysbus_mmio_map(SYS_BUS_DEVICE(vms->ec), 0, vms->memmap[VIRT_EC].base);
+}
+
 static void machvirt_init(MachineState *machine)
 {
     VirtMachineState *vms = VIRT_MACHINE(machine);
@@ -1797,6 +1805,7 @@ static void machvirt_init(MachineState *machine)
      */
     if (vms->secure && firmware_loaded) {
         vms->psci_conduit = QEMU_PSCI_CONDUIT_DISABLED;
+        init_ec_controller(vms);
     } else if (vms->virt) {
         vms->psci_conduit = QEMU_PSCI_CONDUIT_SMC;
     } else {
diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index aad6d69841..6f2ce4e4ff 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -85,6 +85,7 @@ enum {
     VIRT_ACPI_GED,
     VIRT_NVDIMM_ACPI,
     VIRT_PVTIME,
+    VIRT_EC,
     VIRT_LOWMEMMAP_LAST,
 };
 
@@ -163,6 +164,7 @@ struct VirtMachineState {
     DeviceState *gic;
     DeviceState *acpi_dev;
     Notifier powerdown_notifier;
+    DeviceState *ec;
 };
 
 #define VIRT_ECAM_ID(high) (high ? VIRT_HIGH_PCIE_ECAM : VIRT_PCIE_ECAM)
-- 
2.17.1