Hi Palmer, On Sun, Sep 15, 2019 at 3:00 AM Palmer Dabbelt <pal...@sifive.com> wrote: > > On Fri, 13 Sep 2019 08:25:21 PDT (-0700), bmeng...@gmail.com wrote: > > Hi Palmer, > > > > On Fri, Sep 13, 2019 at 10:33 PM Palmer Dabbelt <pal...@sifive.com> wrote: > >> > >> On Fri, 06 Sep 2019 09:20:05 PDT (-0700), bmeng...@gmail.com wrote: > >> > It is not useful if we only have one management CPU. > >> > > >> > Signed-off-by: Bin Meng <bmeng...@gmail.com> > >> > Reviewed-by: Alistair Francis <alistair.fran...@wdc.com> > >> > > >> > --- > >> > > >> > Changes in v8: None > >> > Changes in v7: None > >> > Changes in v6: None > >> > Changes in v5: None > >> > Changes in v4: None > >> > Changes in v3: > >> > - use management cpu count + 1 for the min_cpus > >> > > >> > Changes in v2: > >> > - update the file header to indicate at least 2 harts are created > >> > > >> > hw/riscv/sifive_u.c | 4 +++- > >> > include/hw/riscv/sifive_u.h | 2 ++ > >> > 2 files changed, 5 insertions(+), 1 deletion(-) > >> > > >> > diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c > >> > index 2947e06..2023b71 100644 > >> > --- a/hw/riscv/sifive_u.c > >> > +++ b/hw/riscv/sifive_u.c > >> > @@ -10,7 +10,8 @@ > >> > * 1) CLINT (Core Level Interruptor) > >> > * 2) PLIC (Platform Level Interrupt Controller) > >> > * > >> > - * This board currently uses a hardcoded devicetree that indicates one > >> > hart. > >> > + * This board currently generates devicetree dynamically that indicates > >> > at least > >> > + * two harts. > >> > * > >> > * This program is free software; you can redistribute it and/or modify > >> > it > >> > * under the terms and conditions of the GNU General Public License, > >> > @@ -433,6 +434,7 @@ static void riscv_sifive_u_machine_init(MachineClass > >> > *mc) > >> > * management CPU. > >> > */ > >> > mc->max_cpus = 4; > >> > + mc->min_cpus = SIFIVE_U_MANAGEMENT_CPU_COUNT + 1; > >> > } > >> > > >> > DEFINE_MACHINE("sifive_u", riscv_sifive_u_machine_init) > >> > diff --git a/include/hw/riscv/sifive_u.h b/include/hw/riscv/sifive_u.h > >> > index f25bad8..6d22741 100644 > >> > --- a/include/hw/riscv/sifive_u.h > >> > +++ b/include/hw/riscv/sifive_u.h > >> > @@ -69,6 +69,8 @@ enum { > >> > SIFIVE_U_GEM_CLOCK_FREQ = 125000000 > >> > }; > >> > > >> > +#define SIFIVE_U_MANAGEMENT_CPU_COUNT 1 > >> > + > >> > #define SIFIVE_U_PLIC_HART_CONFIG "MS" > >> > #define SIFIVE_U_PLIC_NUM_SOURCES 54 > >> > #define SIFIVE_U_PLIC_NUM_PRIORITIES 7 > >> > >> This fails "make check", so I'm going to squash in this > >> > >> diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c > >> index ca9f7fea41..adecbf1dd9 100644 > >> --- a/hw/riscv/sifive_u.c > >> +++ b/hw/riscv/sifive_u.c > >> @@ -528,6 +528,7 @@ static void riscv_sifive_u_machine_init(MachineClass > >> *mc) > >> mc->init = riscv_sifive_u_init; > >> mc->max_cpus = SIFIVE_U_MANAGEMENT_CPU_COUNT + > >> SIFIVE_U_COMPUTE_CPU_COUNT; > >> mc->min_cpus = SIFIVE_U_MANAGEMENT_CPU_COUNT + 1; > >> + mc->default_cpus = mc->max_cpus; > > > > Thank you for fixing the 'make check'. Shouldn't it be: > > > > mc->default_cpus = mc->min_cpus; > > We have 5 harts on the board that this matches, so I figured that'd be the > better default. >
Per my understanding mc->default_cpus is used when invoking QEMU without passing '-smp n' (that's what 'make check' uses), and with the updated sifive_u machine, '-smp 2' is the actual useful configuration to boot Linux. For consistency with user experience on other machines, without '-smp' means we want a uni-processor machine hence I would suggest we set "mc->default_cpus = mc->min_cpus". Regards, Bin