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Re: [Qemu-devel] [PATCH for 2.11 5/5] hw: add .min_cpus and .default_cpu
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH for 2.11 5/5] hw: add .min_cpus and .default_cpus fields to machine_class |
Date: |
Fri, 10 Nov 2017 18:32:13 -0200 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
On Fri, Nov 10, 2017 at 02:53:46PM -0500, Emilio G. Cota wrote:
> max_cpus needs to be an upper bound on the number of vCPUs
> initialized; otherwise TCG region initialization breaks.
>
> Some boards initialize a hard-coded number of vCPUs, which is not
> captured by the global max_cpus and therefore breaks TCG initialization.
> Fix it by adding the .min_cpus field to machine_class.
>
> This commit also changes some user-facing behaviour: we now die if
> -smp is below this hard-coded vCPU minimum instead of silently
> ignoring the passed -smp value (sometimes announcing this by printing
> a warning). However, the introduction of .default_cpus lessens the
> likelihood that users will notice this: if -smp isn't set, we now
> assign the value in .default_cpus to both smp_cpus and max_cpus. IOW,
> if a user does not set -smp, they always get a correct number of vCPUs.
>
> This change fixes 3468b59 ("tcg: enable multiple TCG contexts in
> softmmu", 2017-10-24), which broke TCG initialization for some
> ARM boards.
>
> Fixes: 3468b59e18b179bc63c7ce934de912dfa9596122
> Reported-by: Thomas Huth <address@hidden>
> Suggested-by: Peter Maydell <address@hidden>
> Signed-off-by: Emilio G. Cota <address@hidden>
> ---
> include/hw/boards.h | 5 +++++
> hw/arm/exynos4_boards.c | 12 ++++--------
> hw/arm/raspi.c | 2 ++
> hw/arm/xlnx-zcu102.c | 2 ++
> vl.c | 21 ++++++++++++++++++---
> 5 files changed, 31 insertions(+), 11 deletions(-)
>
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 191a5b3..62f160e 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -102,6 +102,9 @@ typedef struct {
>
> /**
> * MachineClass:
> + * @max_cpus: maximum number of CPUs supported. Default: 1
> + * @min_cpus: minimum number of CPUs supported. Default: 1
> + * @default_cpus: number of CPUs instantiated if none are specified.
> Default: 1
> * @get_hotplug_handler: this function is called during bus-less
> * device hotplug. If defined it returns pointer to an instance
> * of HotplugHandler object, which handles hotplug operation
> @@ -167,6 +170,8 @@ struct MachineClass {
> BlockInterfaceType block_default_type;
> int units_per_default_bus;
> int max_cpus;
> + int min_cpus;
> + int default_cpus;
> unsigned int no_serial:1,
> no_parallel:1,
> use_virtcon:1,
> diff --git a/hw/arm/exynos4_boards.c b/hw/arm/exynos4_boards.c
> index f1441ec..750162c 100644
> --- a/hw/arm/exynos4_boards.c
> +++ b/hw/arm/exynos4_boards.c
> @@ -27,7 +27,6 @@
> #include "qemu-common.h"
> #include "cpu.h"
> #include "sysemu/sysemu.h"
> -#include "sysemu/qtest.h"
> #include "hw/sysbus.h"
> #include "net/net.h"
> #include "hw/arm/arm.h"
> @@ -129,13 +128,6 @@ exynos4_boards_init_common(MachineState *machine,
> Exynos4BoardType board_type)
> {
> Exynos4BoardState *s = g_new(Exynos4BoardState, 1);
> - MachineClass *mc = MACHINE_GET_CLASS(machine);
> -
> - if (smp_cpus != EXYNOS4210_NCPUS && !qtest_enabled()) {
> - error_report("%s board supports only %d CPU cores, ignoring smp_cpus"
> - " value",
> - mc->name, EXYNOS4210_NCPUS);
> - }
>
> exynos4_board_binfo.ram_size = exynos4_board_ram_size[board_type];
> exynos4_board_binfo.board_id = exynos4_board_id[board_type];
> @@ -189,6 +181,8 @@ static void nuri_class_init(ObjectClass *oc, void *data)
> mc->desc = "Samsung NURI board (Exynos4210)";
> mc->init = nuri_init;
> mc->max_cpus = EXYNOS4210_NCPUS;
> + mc->min_cpus = EXYNOS4210_NCPUS;
> + mc->default_cpus = EXYNOS4210_NCPUS;
> mc->ignore_memory_transaction_failures = true;
> }
>
> @@ -205,6 +199,8 @@ static void smdkc210_class_init(ObjectClass *oc, void
> *data)
> mc->desc = "Samsung SMDKC210 board (Exynos4210)";
> mc->init = smdkc210_init;
> mc->max_cpus = EXYNOS4210_NCPUS;
> + mc->min_cpus = EXYNOS4210_NCPUS;
> + mc->default_cpus = EXYNOS4210_NCPUS;
> mc->ignore_memory_transaction_failures = true;
> }
>
> diff --git a/hw/arm/raspi.c b/hw/arm/raspi.c
> index 5941c9f..cd5fa8c 100644
> --- a/hw/arm/raspi.c
> +++ b/hw/arm/raspi.c
> @@ -167,6 +167,8 @@ static void raspi2_machine_init(MachineClass *mc)
> mc->no_floppy = 1;
> mc->no_cdrom = 1;
> mc->max_cpus = BCM2836_NCPUS;
> + mc->min_cpus = BCM2836_NCPUS;
> + mc->default_cpus = BCM2836_NCPUS;
> mc->default_ram_size = 1024 * 1024 * 1024;
> mc->ignore_memory_transaction_failures = true;
> };
> diff --git a/hw/arm/xlnx-zcu102.c b/hw/arm/xlnx-zcu102.c
> index 190eb69..9631a53 100644
> --- a/hw/arm/xlnx-zcu102.c
> +++ b/hw/arm/xlnx-zcu102.c
> @@ -189,6 +189,7 @@ static void xlnx_ep108_machine_class_init(ObjectClass
> *oc, void *data)
> mc->units_per_default_bus = 1;
> mc->ignore_memory_transaction_failures = true;
> mc->max_cpus = XLNX_ZYNQMP_NUM_APU_CPUS + XLNX_ZYNQMP_NUM_RPU_CPUS;
> + mc->default_cpus = XLNX_ZYNQMP_NUM_APU_CPUS;
> }
>
> static const TypeInfo xlnx_ep108_machine_init_typeinfo = {
> @@ -246,6 +247,7 @@ static void xlnx_zcu102_machine_class_init(ObjectClass
> *oc, void *data)
> mc->units_per_default_bus = 1;
> mc->ignore_memory_transaction_failures = true;
> mc->max_cpus = XLNX_ZYNQMP_NUM_APU_CPUS + XLNX_ZYNQMP_NUM_RPU_CPUS;
> + mc->default_cpus = XLNX_ZYNQMP_NUM_APU_CPUS;
> }
>
> static const TypeInfo xlnx_zcu102_machine_init_typeinfo = {
> diff --git a/vl.c b/vl.c
> index ec29909..7372424 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -160,8 +160,8 @@ Chardev *virtcon_hds[MAX_VIRTIO_CONSOLES];
> Chardev *sclp_hds[MAX_SCLP_CONSOLES];
> int win2k_install_hack = 0;
> int singlestep = 0;
> -int smp_cpus = 1;
> -unsigned int max_cpus = 1;
> +int smp_cpus;
> +unsigned int max_cpus;
> int smp_cores = 1;
> int smp_threads = 1;
> int acpi_enabled = 1;
> @@ -4327,9 +4327,24 @@ int main(int argc, char **argv, char **envp)
> exit(0);
> }
>
> + /* machine_class: default to UP */
> + machine_class->max_cpus = machine_class->max_cpus ?: 1;
> + machine_class->min_cpus = machine_class->min_cpus ?: 1;
> + machine_class->default_cpus = machine_class->default_cpus ?: 1;
This is consistent with the existing code that initialized
max_cpus, but I'd prefer to initialize these defaults inside
hw/core/machine.c:machine_class_init(). It can be done in a
follow-up patch after 2.11, though.
> +
> + /* default to machine_class->default_cpus */
> + smp_cpus = machine_class->default_cpus;
> + max_cpus = machine_class->default_cpus;
> +
> smp_parse(qemu_opts_find(qemu_find_opts("smp-opts"), NULL));
>
> - machine_class->max_cpus = machine_class->max_cpus ?: 1; /* Default to UP
> */
> + /* sanity-check smp_cpus and max_cpus against machine_class */
> + if (smp_cpus < machine_class->min_cpus) {
> + error_report("Invalid SMP CPUs %d. The min CPUs "
> + "supported by machine '%s' is %d", smp_cpus,
> + machine_class->name, machine_class->min_cpus);
> + exit(1);
> + }
> if (max_cpus > machine_class->max_cpus) {
> error_report("Invalid SMP CPUs %d. The max CPUs "
> "supported by machine '%s' is %d", max_cpus,
Reviewed-by: Eduardo Habkost <address@hidden>
--
Eduardo
- [Qemu-devel] [PATCH for 2.11 0/5] TCG/ARM fixes for 2.11, Emilio G. Cota, 2017/11/10
- [Qemu-devel] [PATCH for 2.11 1/5] qom: move CPUClass.tcg_initialize to a global, Emilio G. Cota, 2017/11/10
- [Qemu-devel] [PATCH for 2.11 3/5] xlnx-zcu102: Add an info message deprecating the EP108, Emilio G. Cota, 2017/11/10
- [Qemu-devel] [PATCH for 2.11 4/5] xlnx-zcu102: Specify the max number of CPUs for the EP108, Emilio G. Cota, 2017/11/10
- [Qemu-devel] [PATCH for 2.11 5/5] hw: add .min_cpus and .default_cpus fields to machine_class, Emilio G. Cota, 2017/11/10
- [Qemu-devel] [PATCH for 2.11 2/5] xlnx-zynqmp: Properly support the smp command line option, Emilio G. Cota, 2017/11/10
- Re: [Qemu-devel] [PATCH for 2.11 0/5] TCG/ARM fixes for 2.11, Peter Maydell, 2017/11/13