[Qemu-devel] [PATCH 13/27] acpi: memory hotplug ACPI hardware implementation

[Igor Mammedov <imammedo@redhat.com>]

- implements QEMU hardware part of memory hotplug protocol
  described at "docs/specs/acpi_mem_hotplug.txt"
- handles only memory add notification event for now

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 docs/specs/acpi_mem_hotplug.txt |   38 ++++++++++
 hw/acpi/core.c                  |  144 +++++++++++++++++++++++++++++++++++++++
 include/hw/acpi/acpi.h          |   24 +++++++
 3 files changed, 206 insertions(+), 0 deletions(-)
 create mode 100644 docs/specs/acpi_mem_hotplug.txt

diff --git a/docs/specs/acpi_mem_hotplug.txt b/docs/specs/acpi_mem_hotplug.txt
new file mode 100644
index 0000000..fc34142
--- /dev/null
+++ b/docs/specs/acpi_mem_hotplug.txt
@@ -0,0 +1,38 @@
+QEMU<->ACPI BIOS memory hotplug interface
+--------------------------------------
+
+ACPI BIOS GPE.3 handler is dedicated for notifying OS about memory hot-add
+or hot-remove events.
+
+Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
+---------------------------------------------------------------
+0xa00:
+  read access:
+      [0x0-0x3] Lo part of memory device phys address
+      [0x4-0x7] Hi part of memory device phys address
+      [0x8-0xb] Lo part of memory device size in bytes
+      [0xc-0xf] Hi part of memory device size in bytes
+      [0x14] highest memory hot-plug interface version supported by QEMU
+      [0x15] Memory device status fields
+          bits:
+              1: device is enabled and may be used by guest
+              2: device insert event, used by ACPI BIOS to distinguish
+                 device for which no device check event to OSPM was issued
+      [0x16-0x17] reserved
+
+  write access:
+      [0x0-0x3] Memory device slot selector, selects active memory device.
+                All following accesses to other registers in 0xaf80-0xaf97
+                region will read/store data from/to selected memory device.
+      [0x4-0x7] OST event code reported by OSPM
+      [0x8-0xb] OST status code reported by OSPM
+      [0x15] Memory device status fields
+          bits:
+              2: if set to 1 clears device insert event, set by ACPI BIOS
+                 after it has sent device check event to OSPM for
+                 seleted memory device
+
+Selecting memory device slot beyond present range has no effect on platform:
+   - not documented above write accesses to memory hot-plug registers
+     are ignored;
+   - not documented above read accesses to memory hot-plug registers return 0xFF
diff --git a/hw/acpi/core.c b/hw/acpi/core.c
index 8c0d48c..18e169c 100644
--- a/hw/acpi/core.c
+++ b/hw/acpi/core.c
@@ -680,3 +680,147 @@ void acpi_update_sci(ACPIREGS *regs, qemu_irq irq, uint32_t gpe0_sts_mask)
                        (regs->pm1.evt.en & ACPI_BITMASK_TIMER_ENABLE) &&
                        !(pm1a_sts & ACPI_BITMASK_TIMER_STATUS));
 }
+
+static uint64_t acpi_memory_hotplug_read(void *opaque, hwaddr addr,
+                                         unsigned int size)
+{
+    uint32_t val = 0;
+    MemHotplugState *mem_st = opaque;
+    MemStatus *mdev;
+
+    if (mem_st->selector >= mem_st->dev_count) {
+        return 0;
+    }
+
+    mdev = &mem_st->devs[mem_st->selector];
+    switch (addr) {
+    case 0x0: /* Lo part of phys address where DIMM is mapped */
+        val = object_property_get_int(OBJECT(mdev->dimm), "start", NULL);
+        break;
+    case 0x4: /* Hi part of phys address where DIMM is mapped */
+        val = object_property_get_int(OBJECT(mdev->dimm), "start", NULL) >> 32;
+        break;
+    case 0x8: /* Lo part of DIMM size */
+        val = object_property_get_int(OBJECT(mdev->dimm), "size", NULL);
+        break;
+    case 0xc: /* Hi part of DIMM size */
+        val = object_property_get_int(OBJECT(mdev->dimm), "size", NULL) >> 32;
+        break;
+    case 0x10: /* node proximity for _PXM method */
+        val = object_property_get_int(OBJECT(mdev->dimm), "node", NULL);
+        break;
+    case 0x14: /* intf version */
+        val = 1;
+        break;
+    case 0x15: /* pack and return is_* fields */
+        val |= mdev->is_enabled   ? 1 : 0;
+        val |= mdev->is_inserting ? 2 : 0;
+        break;
+    }
+    return val;
+}
+
+static void acpi_memory_hotplug_write(void *opaque, hwaddr addr, uint64_t data,
+                                      unsigned int size)
+{
+    MemHotplugState *mem_st = opaque;
+    MemStatus *mdev;
+
+    if (!mem_st->dev_count) {
+        return;
+    }
+
+    if (addr) {
+        if (mem_st->selector >= mem_st->dev_count) {
+            return;
+        }
+    }
+
+    switch (addr) {
+    case 0x0: /* DIMM slot selector */
+        mem_st->selector = data;
+        break;
+    case 0x4: /* _OST event  */
+        mdev = &mem_st->devs[mem_st->selector];
+        if (data == 1) {
+            /* TODO: handle device insert OST event */
+        } else if (data == 3) {
+            /* TODO: handle device remove OST event */
+        }
+        mdev->ost_event = data;
+        break;
+    case 0x8: /* _OST status */
+        mdev = &mem_st->devs[mem_st->selector];
+        mdev->ost_status = data;
+        /* TODO: report async error */
+        /* TODO: implement memory removal on guest signal */
+        break;
+    case 0x15:
+        mdev = &mem_st->devs[mem_st->selector];
+        if (data & 2) { /* clear insert event */
+            mdev->is_inserting  = false;
+        }
+        break;
+    }
+
+}
+static const MemoryRegionOps acpi_memory_hotplug_ops = {
+    .read = acpi_memory_hotplug_read,
+    .write = acpi_memory_hotplug_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 4,
+    },
+};
+
+void acpi_memory_hotplug_init(Object *owner, MemoryRegion *io,
+                              MemHotplugState *state)
+{
+    QemuOpts *opts = qemu_opts_find(qemu_find_opts("memory-opts"), NULL);
+    g_assert(opts);
+
+    state->dev_count = qemu_opt_get_number(opts, "slots", 0);
+
+    if (!state->dev_count) {
+        return;
+    }
+
+    state->devs = g_malloc0(sizeof(*state->devs) * state->dev_count);
+    memory_region_init_io(io, owner, &acpi_memory_hotplug_ops, state,
+                          "apci-mem-hotplug", ACPI_MEMORY_HOTPLUG_IO_LEN);
+}
+
+int acpi_memory_hotplug_cb(ACPIREGS *regs, MemHotplugState *mem_st,
+                           DeviceState *dev, HotplugState state)
+{
+    MemStatus *mdev;
+    Error *local_err = NULL;
+    int slot = object_property_get_int(OBJECT(dev), "slot", &local_err);
+
+    if (error_is_set(&local_err)) {
+        qerror_report_err(local_err);
+        error_free(local_err);
+        return -1;
+    }
+
+    if (slot >= mem_st->dev_count) {
+        char *dev_path = object_get_canonical_path(OBJECT(dev));
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "acpi_memory_hotplug_cb: "
+                      "device [%s] returned invalid memory slot[%d]",
+                      dev_path, slot);
+        g_free(dev_path);
+        return -1;
+    }
+
+    mdev = &mem_st->devs[slot];
+    if (state == HOTPLUG_ENABLED) {
+        mdev->dimm = dev;
+        mdev->is_enabled = true;
+        mdev->is_inserting = true;
+    }
+
+    /* do ACPI magic */
+    regs->gpe.sts[0] |= ACPI_MEMORY_HOTPLUG_STATUS;
+    return 0;
+}
diff --git a/include/hw/acpi/acpi.h b/include/hw/acpi/acpi.h
index c4ae7d7..e5717df 100644
--- a/include/hw/acpi/acpi.h
+++ b/include/hw/acpi/acpi.h
@@ -168,6 +168,30 @@ uint32_t acpi_gpe_ioport_readb(ACPIREGS *ar, uint32_t addr);
 
 void acpi_update_sci(ACPIREGS *acpi_regs, qemu_irq irq, uint32_t gpe0_sts_mask);
 
+#define ACPI_MEMORY_HOTPLUG_IO_LEN 24
+#define ACPI_MEMORY_HOTPLUG_BASE 0x0a00
+
+#define ACPI_MEMORY_HOTPLUG_STATUS 8
+
+typedef struct MemStatus {
+    DeviceState *dimm;
+    bool is_enabled;
+    bool is_inserting;
+    uint32_t ost_event;
+    uint32_t ost_status;
+} MemStatus;
+
+typedef struct MemHotplugState {
+    uint32_t selector;
+    uint32_t dev_count;
+    MemStatus *devs;
+} MemHotplugState;
+
+void acpi_memory_hotplug_init(Object *owner, MemoryRegion *io,
+                              MemHotplugState *state);
+
+int acpi_memory_hotplug_cb(ACPIREGS *regs, MemHotplugState *mem_st,
+                           DeviceState *dev, HotplugState state);
 /* acpi.c */
 extern int acpi_enabled;
 extern char unsigned *acpi_tables;
-- 
1.7.1