On 13.03.15 12:56, Bharata B Rao wrote: > From: Bharata B Rao <bharata....@gmail.com> > > Currently CPUState.cpu_index is monotonically increasing and a newly > created CPU always gets the next higher index. The next available > index is calculated by counting the existing number of CPUs. This is > fine as long as we only add CPUs, but there are architectures which > are starting to support CPU removal too. For an architecture like PowerPC > which derives its CPU identifier (device tree ID) from cpu_index, the > existing logic of generating cpu_index values causes problems. > > With the currently proposed method of handling vCPU removal by parking > the vCPU fd in QEMU > (Ref: http://lists.gnu.org/archive/html/qemu-devel/2015-02/msg02604.html), > generating cpu_index this way will not work for PowerPC. > > This patch changes the way cpu_index is handed out by maintaining > a bit map of the CPUs that tracks both addition and removal of CPUs. > > I am not sure if this is the right and an acceptable approach. The > alternative is to do something similar for PowerPC alone and not > depend on cpu_index. > > I have tested this with out-of-the-tree patches for CPU hot plug and > removal on x86 and sPAPR PowerPC. > > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com> > --- > exec.c | 39 +++++++++++++++++++++++++++++---------- > include/exec/exec-all.h | 1 + > target-alpha/cpu.c | 6 ++++++ > target-arm/cpu.c | 1 + > target-cris/cpu.c | 6 ++++++ > target-i386/cpu.c | 6 ++++++ > target-lm32/cpu.c | 6 ++++++ > target-m68k/cpu.c | 6 ++++++ > target-microblaze/cpu.c | 6 ++++++ > target-mips/cpu.c | 6 ++++++ > target-moxie/cpu.c | 6 ++++++ > target-openrisc/cpu.c | 6 ++++++ > target-ppc/translate_init.c | 6 ++++++ > target-s390x/cpu.c | 1 + > target-sh4/cpu.c | 6 ++++++ > target-sparc/cpu.c | 1 + > target-tricore/cpu.c | 5 +++++ > target-unicore32/cpu.c | 6 ++++++ > target-xtensa/cpu.c | 6 ++++++ > 19 files changed, 116 insertions(+), 10 deletions(-) > > diff --git a/exec.c b/exec.c > index e97071a..7760f2d 100644 > --- a/exec.c > +++ b/exec.c > @@ -530,21 +530,40 @@ void tcg_cpu_address_space_init(CPUState *cpu, > AddressSpace *as) > } > #endif > > +static DECLARE_BITMAP(cpu_index_map, MAX_CPUMASK_BITS); > + > +#ifdef CONFIG_USER_ONLY > +int max_cpus = 1; /* TODO: Check if this is correct ? */ > +#endif > + > +static int cpu_get_free_index(void) > +{ > + int cpu = find_first_zero_bit(cpu_index_map, max_cpus); > + > + if (cpu == max_cpus) { > + fprintf(stderr, "WARNING: qemu: Trying to use more " > + "CPUs than allowed max of %d\n", max_cpus); > + return max_cpus; > + } else { > + bitmap_set(cpu_index_map, cpu, 1); > + return cpu; > + } > +} > + > +void cpu_exec_exit(CPUState *cpu) > +{ > + bitmap_clear(cpu_index_map, cpu->cpu_index, 1); > +} > + > void cpu_exec_init(CPUArchState *env) > { > CPUState *cpu = ENV_GET_CPU(env); > CPUClass *cc = CPU_GET_CLASS(cpu); > - CPUState *some_cpu; > - int cpu_index; > > #if defined(CONFIG_USER_ONLY) > cpu_list_lock(); > #endif > - cpu_index = 0; > - CPU_FOREACH(some_cpu) { > - cpu_index++; > - } > - cpu->cpu_index = cpu_index; > + cpu->cpu_index = cpu_get_free_index(); > cpu->numa_node = 0; > QTAILQ_INIT(&cpu->breakpoints); > QTAILQ_INIT(&cpu->watchpoints); > @@ -558,16 +577,16 @@ void cpu_exec_init(CPUArchState *env) > cpu_list_unlock(); > #endif > if (qdev_get_vmsd(DEVICE(cpu)) == NULL) { > - vmstate_register(NULL, cpu_index, &vmstate_cpu_common, cpu); > + vmstate_register(NULL, cpu->cpu_index, &vmstate_cpu_common, cpu); > } > #if defined(CPU_SAVE_VERSION) && !defined(CONFIG_USER_ONLY) > - register_savevm(NULL, "cpu", cpu_index, CPU_SAVE_VERSION, > + register_savevm(NULL, "cpu", cpu->cpu_index, CPU_SAVE_VERSION, > cpu_save, cpu_load, env); > assert(cc->vmsd == NULL); > assert(qdev_get_vmsd(DEVICE(cpu)) == NULL); > #endif > if (cc->vmsd != NULL) { > - vmstate_register(NULL, cpu_index, cc->vmsd, cpu); > + vmstate_register(NULL, cpu->cpu_index, cc->vmsd, cpu); > } > } > > diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h > index 8eb0db3..95fbba0 100644 > --- a/include/exec/exec-all.h > +++ b/include/exec/exec-all.h > @@ -89,6 +89,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, > target_ulong pc, target_ulong cs_base, int > flags, > int cflags); > void cpu_exec_init(CPUArchState *env); > +void cpu_exec_exit(CPUState *cpu); > void QEMU_NORETURN cpu_loop_exit(CPUState *cpu); > int page_unprotect(target_ulong address, uintptr_t pc, void *puc); > void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end, > diff --git a/target-alpha/cpu.c b/target-alpha/cpu.c > index a98b7d8..7c57165 100644 > --- a/target-alpha/cpu.c > +++ b/target-alpha/cpu.c > @@ -250,6 +250,11 @@ static const TypeInfo ev68_cpu_type_info = { > .parent = TYPE("ev67"), > }; > > +static void alpha_cpu_finalize(Object *obj) > +{ > + cpu_exec_exit(CPU(obj)); > +} > + > static void alpha_cpu_initfn(Object *obj) > { > CPUState *cs = CPU(obj); > @@ -305,6 +310,7 @@ static const TypeInfo alpha_cpu_type_info = { > .parent = TYPE_CPU, > .instance_size = sizeof(AlphaCPU), > .instance_init = alpha_cpu_initfn, > + .instance_finalize = alpha_cpu_finalize,
Would it be possible to put this into TYPE_CPU->instance_finalize instead? Alex
