pseries: Implement PAPR NVRAM

The PAPR specification requires a certain amount of NVRAM, accessed via
RTAS, which we don't currently implement in qemu.  This patch addresses
this deficiency, implementing the NVRAM as a VIO device, with some glue to
instantiate it automatically based on a machine option.

The machine option specifies a drive id, which is used to back the NVRAM,
making it persistent.  If nothing is specified, the driver instead simply
allocates space for the NVRAM, which will not be persistent

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>

5 files changed, 236 insertions, 1 deletions

diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
index 8fe21235f0..44921273c3 100644
--- a/hw/ppc/Makefile.objs
+++ b/hw/ppc/Makefile.objs
@@ -11,7 +11,7 @@ obj-y += ppc_newworld.o
 obj-$(CONFIG_PSERIES) += spapr.o spapr_hcall.o spapr_rtas.o spapr_vio.o
 obj-$(CONFIG_PSERIES) += xics.o spapr_vty.o spapr_llan.o spapr_vscsi.o
 obj-$(CONFIG_PSERIES) += spapr_pci.o pci-hotplug.o spapr_iommu.o
-obj-$(CONFIG_PSERIES) += spapr_events.o
+obj-$(CONFIG_PSERIES) += spapr_events.o spapr_nvram.o
 # PowerPC 4xx boards
 obj-y += ppc4xx_devs.o ppc4xx_pci.o ppc405_uc.o ppc405_boards.o
 obj-y += ppc440_bamboo.o
diff --git a/hw/spapr.c b/hw/spapr.c
index eafee0313d..d23aa9d7c1 100644
--- a/hw/spapr.c
+++ b/hw/spapr.c
@@ -657,6 +657,36 @@ static void spapr_cpu_reset(void *opaque)
         (spapr->htab_shift - 18);
 }
 
+static void spapr_create_nvram(sPAPREnvironment *spapr)
+{
+    QemuOpts *machine_opts;
+    DeviceState *dev;
+
+    dev = qdev_create(&spapr->vio_bus->bus, "spapr-nvram");
+
+    machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0);
+    if (machine_opts) {
+        const char *drivename;
+
+        drivename = qemu_opt_get(machine_opts, "nvram");
+        if (drivename) {
+            BlockDriverState *bs;
+
+            bs = bdrv_find(drivename);
+            if (!bs) {
+                fprintf(stderr, "No such block device \"%s\" for nvram\n",
+                        drivename);
+                exit(1);
+            }
+            qdev_prop_set_drive_nofail(dev, "drive", bs);
+        }
+    }
+
+    qdev_init_nofail(dev);
+
+    spapr->nvram = (struct sPAPRNVRAM *)dev;
+}
+
 /* Returns whether we want to use VGA or not */
 static int spapr_vga_init(PCIBus *pci_bus)
 {
@@ -818,6 +848,9 @@ static void ppc_spapr_init(QEMUMachineInitArgs *args)
         }
     }
 
+    /* We always have at least the nvram device on VIO */
+    spapr_create_nvram(spapr);
+
     /* Set up PCI */
     spapr_pci_rtas_init();
 
diff --git a/hw/spapr.h b/hw/spapr.h
index 971a50ab02..600722f132 100644
--- a/hw/spapr.h
+++ b/hw/spapr.h
@@ -6,11 +6,13 @@
 
 struct VIOsPAPRBus;
 struct sPAPRPHBState;
+struct sPAPRNVRAM;
 struct icp_state;
 
 typedef struct sPAPREnvironment {
     struct VIOsPAPRBus *vio_bus;
     QLIST_HEAD(, sPAPRPHBState) phbs;
+    struct sPAPRNVRAM *nvram;
     struct icp_state *icp;
 
     hwaddr ram_limit;
diff --git a/hw/spapr_nvram.c b/hw/spapr_nvram.c
new file mode 100644
index 0000000000..641de485f9
--- /dev/null
+++ b/hw/spapr_nvram.c
@@ -0,0 +1,196 @@
+/*
+ * QEMU sPAPR NVRAM emulation
+ *
+ * Copyright (C) 2012 David Gibson, IBM Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include <sys/mman.h>
+#include <libfdt.h>
+
+#include "device_tree.h"
+#include "hw/sysbus.h"
+#include "hw/spapr.h"
+#include "hw/spapr_vio.h"
+
+typedef struct sPAPRNVRAM {
+    VIOsPAPRDevice sdev;
+    uint32_t size;
+    uint8_t *buf;
+    BlockDriverState *drive;
+} sPAPRNVRAM;
+
+#define MIN_NVRAM_SIZE 8192
+#define DEFAULT_NVRAM_SIZE 16384
+#define MAX_NVRAM_SIZE (UINT16_MAX * 16)
+
+static void rtas_nvram_fetch(sPAPREnvironment *spapr,
+                             uint32_t token, uint32_t nargs,
+                             target_ulong args,
+                             uint32_t nret, target_ulong rets)
+{
+    sPAPRNVRAM *nvram = spapr->nvram;
+    hwaddr offset, buffer, len;
+    int alen;
+    void *membuf;
+
+    if ((nargs != 3) || (nret != 2)) {
+        rtas_st(rets, 0, -3);
+        return;
+    }
+
+    if (!nvram) {
+        rtas_st(rets, 0, -1);
+        rtas_st(rets, 1, 0);
+        return;
+    }
+
+    offset = rtas_ld(args, 0);
+    buffer = rtas_ld(args, 1);
+    len = rtas_ld(args, 2);
+
+    if (((offset + len) < offset)
+        || ((offset + len) > nvram->size)) {
+        rtas_st(rets, 0, -3);
+        rtas_st(rets, 1, 0);
+        return;
+    }
+
+    membuf = cpu_physical_memory_map(buffer, &len, 1);
+    if (nvram->drive) {
+        alen = bdrv_pread(nvram->drive, offset, membuf, len);
+    } else {
+        assert(nvram->buf);
+
+        memcpy(membuf, nvram->buf + offset, len);
+        alen = len;
+    }
+    cpu_physical_memory_unmap(membuf, len, 1, len);
+
+    rtas_st(rets, 0, (alen < len) ? -1 : 0);
+    rtas_st(rets, 1, (alen < 0) ? 0 : alen);
+}
+
+static void rtas_nvram_store(sPAPREnvironment *spapr,
+                             uint32_t token, uint32_t nargs,
+                             target_ulong args,
+                             uint32_t nret, target_ulong rets)
+{
+    sPAPRNVRAM *nvram = spapr->nvram;
+    hwaddr offset, buffer, len;
+    int alen;
+    void *membuf;
+
+    if ((nargs != 3) || (nret != 2)) {
+        rtas_st(rets, 0, -3);
+        return;
+    }
+
+    if (!nvram) {
+        rtas_st(rets, 0, -1);
+        return;
+    }
+
+    offset = rtas_ld(args, 0);
+    buffer = rtas_ld(args, 1);
+    len = rtas_ld(args, 2);
+
+    if (((offset + len) < offset)
+        || ((offset + len) > nvram->size)) {
+        rtas_st(rets, 0, -3);
+        return;
+    }
+
+    membuf = cpu_physical_memory_map(buffer, &len, 0);
+    if (nvram->drive) {
+        alen = bdrv_pwrite(nvram->drive, offset, membuf, len);
+    } else {
+        assert(nvram->buf);
+
+        memcpy(nvram->buf + offset, membuf, len);
+        alen = len;
+    }
+    cpu_physical_memory_unmap(membuf, len, 0, len);
+
+    rtas_st(rets, 0, (alen < len) ? -1 : 0);
+    rtas_st(rets, 1, (alen < 0) ? 0 : alen);
+}
+
+static int spapr_nvram_init(VIOsPAPRDevice *dev)
+{
+    sPAPRNVRAM *nvram = (sPAPRNVRAM *)dev;
+
+    if (nvram->drive) {
+        nvram->size = bdrv_getlength(nvram->drive);
+    } else {
+        nvram->size = DEFAULT_NVRAM_SIZE;
+        nvram->buf = g_malloc0(nvram->size);
+    }
+
+    if ((nvram->size < MIN_NVRAM_SIZE) || (nvram->size > MAX_NVRAM_SIZE)) {
+        fprintf(stderr, "spapr-nvram must be between %d and %d bytes in size\n",
+                MIN_NVRAM_SIZE, MAX_NVRAM_SIZE);
+        return -1;
+    }
+
+    spapr_rtas_register("nvram-fetch", rtas_nvram_fetch);
+    spapr_rtas_register("nvram-store", rtas_nvram_store);
+
+    return 0;
+}
+
+static int spapr_nvram_devnode(VIOsPAPRDevice *dev, void *fdt, int node_off)
+{
+    sPAPRNVRAM *nvram = (sPAPRNVRAM *)dev;
+
+    return fdt_setprop_cell(fdt, node_off, "#bytes", nvram->size);
+}
+
+static Property spapr_nvram_properties[] = {
+    DEFINE_SPAPR_PROPERTIES(sPAPRNVRAM, sdev),
+    DEFINE_PROP_DRIVE("drive", sPAPRNVRAM, drive),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void spapr_nvram_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VIOsPAPRDeviceClass *k = VIO_SPAPR_DEVICE_CLASS(klass);
+
+    k->init = spapr_nvram_init;
+    k->devnode = spapr_nvram_devnode;
+    k->dt_name = "nvram";
+    k->dt_type = "nvram";
+    k->dt_compatible = "qemu,spapr-nvram";
+    dc->props = spapr_nvram_properties;
+}
+
+static const TypeInfo spapr_nvram_type_info = {
+    .name          = "spapr-nvram",
+    .parent        = TYPE_VIO_SPAPR_DEVICE,
+    .instance_size = sizeof(sPAPRNVRAM),
+    .class_init    = spapr_nvram_class_init,
+};
+
+static void spapr_nvram_register_types(void)
+{
+    type_register_static(&spapr_nvram_type_info);
+}
+
+type_init(spapr_nvram_register_types)
diff --git a/qemu-config.c b/qemu-config.c
index aa78fb9ea7..de10051654 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -579,6 +579,10 @@ static QemuOptsList qemu_machine_opts = {
             .name = "usb",
             .type = QEMU_OPT_BOOL,
             .help = "Set on/off to enable/disable usb",
+        }, {
+            .name = "nvram",
+            .type = QEMU_OPT_STRING,
+            .help = "Drive backing persistent NVRAM",
         },
         { /* End of list */ }
     },