From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53779) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eCAHw-0006I5-BY for qemu-devel@nongnu.org; Tue, 07 Nov 2017 15:16:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eCAHu-0006Iz-Rv for qemu-devel@nongnu.org; Tue, 07 Nov 2017 15:16:00 -0500 Date: Tue, 7 Nov 2017 18:15:45 -0200 From: Eduardo Habkost Message-ID: <20171107201545.GA32606@localhost.localdomain> References: <1509734853-3014-1-git-send-email-cota@braap.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1509734853-3014-1-git-send-email-cota@braap.org> Subject: Re: [Qemu-devel] [PATCH] hw: add .min_cpus and .default_cpus fields to machine_class List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Emilio G. Cota" Cc: qemu-devel@nongnu.org, Peter Maydell , Thomas Huth , Igor Mitsyanko , Richard Henderson , Alistair Francis , qemu-arm@nongnu.org, Marcel Apfelbaum , "Edgar E . Iglesias" On Fri, Nov 03, 2017 at 02:47:33PM -0400, 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. 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 > Suggested-by: Peter Maydell > Signed-off-by: Emilio G. Cota > --- > hw/arm/exynos4_boards.c | 12 ++++-------- > hw/arm/raspi.c | 2 ++ > hw/arm/xlnx-zcu102.c | 5 +++++ > include/hw/boards.h | 5 +++++ > vl.c | 28 +++++++++++++++++++++++++--- > 5 files changed, 41 insertions(+), 11 deletions(-) > > 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 e2d15a1..395d1b5 100644 > --- a/hw/arm/xlnx-zcu102.c > +++ b/hw/arm/xlnx-zcu102.c > @@ -185,6 +185,9 @@ static void xlnx_ep108_machine_class_init(ObjectClass *oc, void *data) > mc->block_default_type = IF_IDE; > 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->min_cpus = XLNX_ZYNQMP_NUM_APU_CPUS; > + mc->default_cpus = XLNX_ZYNQMP_NUM_APU_CPUS; > } > > static const TypeInfo xlnx_ep108_machine_init_typeinfo = { > @@ -241,6 +244,8 @@ 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->min_cpus = XLNX_ZYNQMP_NUM_APU_CPUS; > + mc->default_cpus = XLNX_ZYNQMP_NUM_APU_CPUS; > } > > static const TypeInfo xlnx_zcu102_machine_init_typeinfo = { > 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/vl.c b/vl.c > index ec29909..3ca5ee8 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; > @@ -4330,12 +4330,34 @@ int main(int argc, char **argv, char **envp) > smp_parse(qemu_opts_find(qemu_find_opts("smp-opts"), NULL)); > > machine_class->max_cpus = machine_class->max_cpus ?: 1; /* Default to UP */ > + machine_class->min_cpus = machine_class->min_cpus ?: 1; > + machine_class->default_cpus = machine_class->default_cpus ?: 1; > + > + /* if -smp is not set, default to mc->default_cpus */ > + if (!smp_cpus) { > + smp_cpus = machine_class->default_cpus; > + max_cpus = machine_class->default_cpus; > + } I suggest doing this before smp_parse(), so any validation of smp_cpus inside smp_parse will apply to the value we're setting here (e.g. the replay_add_blocker() call in smp_parse() will work). > + > + /* sanity-check smp_cpus and max_cpus */ > + 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 " > + error_report("Invalid max SMP CPUs %d. The max CPUs " > "supported by machine '%s' is %d", max_cpus, > machine_class->name, machine_class->max_cpus); > exit(1); > } > + if (max_cpus < machine_class->min_cpus) { smp_parse() already ensures max_cpus >= smp_cpus, and you are already checking if smp_cpus < machine_class->min_cpus above. Is it really possible to trigger this error message? Except for that, the patch looks good to me. > + error_report("Invalid max SMP CPUs %d. The min CPUs " > + "supported by machine '%s' is %d", max_cpus, > + machine_class->name, machine_class->min_cpus); > + exit(1); > + } > > /* > * Get the default machine options from the machine if it is not already > -- > 2.7.4 > > -- Eduardo