[Qemu-devel] [PATCH for-2.1 2/2] i386/acpi-build: support hotplug of VCPU with APIC ID 0xFF

[Laszlo Ersek]

Building on the previous patch, raise the maximal count of processor
objects / NTFY branches / CPON elements from 255 to 256. This allows the
VCPU with APIC ID 0xFF to be hotplugged.

Signed-off-by: Laszlo Ersek <address@hidden>
---
 hw/i386/acpi-build.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 2bbefb5..51162fc 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -999,11 +999,15 @@ build_ssdt(GArray *table_data, GArray *linker,
            AcpiCpuInfo *cpu, AcpiPmInfo *pm, AcpiMiscInfo *misc,
            PcPciInfo *pci, PcGuestInfo *guest_info)
 {
-    int acpi_cpus = MIN(0xff, guest_info->apic_id_limit);
     int ssdt_start = table_data->len;
     uint8_t *ssdt_ptr;
     int i;
 
+    /* The current AML generator can cover the APIC ID range [0..255],
+     * inclusive, for VCPU hotplug. */
+    QEMU_BUILD_BUG_ON(ACPI_CPU_HOTPLUG_ID_LIMIT > 256);
+    g_assert(guest_info->apic_id_limit <= ACPI_CPU_HOTPLUG_ID_LIMIT);
+
     /* Copy header and patch values in the S3_ / S4_ / S5_ packages */
     ssdt_ptr = acpi_data_push(table_data, sizeof(ssdp_misc_aml));
     memcpy(ssdt_ptr, ssdp_misc_aml, sizeof(ssdp_misc_aml));
@@ -1029,7 +1033,7 @@ build_ssdt(GArray *table_data, GArray *linker,
         build_append_nameseg(sb_scope, "_SB_");
 
         /* build Processor object for each processor */
-        for (i = 0; i < acpi_cpus; i++) {
+        for (i = 0; i < guest_info->apic_id_limit; i++) {
             uint8_t *proc = acpi_data_push(sb_scope, ACPI_PROC_SIZEOF);
             memcpy(proc, ACPI_PROC_AML, ACPI_PROC_SIZEOF);
             proc[ACPI_PROC_OFFSET_CPUHEX] = acpi_get_hex(i >> 4);
@@ -1042,7 +1046,8 @@ build_ssdt(GArray *table_data, GArray *linker,
          *   Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}
          */
         /* Arg0 = Processor ID = APIC ID */
-        build_append_notify_method(sb_scope, "NTFY", "CP%0.02X", acpi_cpus);
+        build_append_notify_method(sb_scope, "NTFY", "CP%0.02X",
+                                   guest_info->apic_id_limit);
 
         /* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })" */
         build_append_byte(sb_scope, 0x08); /* NameOp */
@@ -1052,8 +1057,9 @@ build_ssdt(GArray *table_data, GArray *linker,
             GArray *package = build_alloc_array();
             uint8_t op = 0x13; /* VarPackageOp */
 
-            build_append_int(package, acpi_cpus); /* VarNumElements */
-            for (i = 0; i < acpi_cpus; i++) {
+            build_append_int(package,
+                             guest_info->apic_id_limit); /* VarNumElements */
+            for (i = 0; i < guest_info->apic_id_limit; i++) {
                 uint8_t b = test_bit(i, cpu->found_cpus) ? 0x01 : 0x00;
                 build_append_byte(package, b);
             }
-- 
1.8.3.1