On Mon, Aug 15, 2016 at 11:58:46AM +1000, Suraj Jitindar Singh wrote:
> On Fri, 2016-08-12 at 19:07 +0200, Andrew Jones wrote:
> > On Wed, Aug 10, 2016 at 11:59:36AM +1000, Suraj Jitindar Singh wrote:
> > >
> > > Add the lib/powerpc/smp.c file and associated header files as a
> > > place
> > > to implement generic smp functionality for inclusion in tests.
> > >
> > > Add functions start_all_cpus(), start_cpu() and start_thread() to
> > > start
> > > all stopped threads of all cpus, all stopped threads of a single
> > > cpu or a
> > > single stopped thread of a guest at a given execution location,
> > > respectively.
> > >
> > > Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
> > > ---
> > > lib/powerpc/asm/smp.h | 15 +++++++
> > > lib/powerpc/smp.c | 115
> > > ++++++++++++++++++++++++++++++++++++++++++++++++
> > > lib/ppc64/asm/smp.h | 1 +
> > > powerpc/Makefile.common | 1 +
> > > 4 files changed, 132 insertions(+)
> > > create mode 100644 lib/powerpc/asm/smp.h
> > > create mode 100644 lib/powerpc/smp.c
> > > create mode 100644 lib/ppc64/asm/smp.h
> > >
> > > diff --git a/lib/powerpc/asm/smp.h b/lib/powerpc/asm/smp.h
> > > new file mode 100644
> > > index 0000000..a4f3e7f
> > > --- /dev/null
> > > +++ b/lib/powerpc/asm/smp.h
> > > @@ -0,0 +1,15 @@
> > > +#ifndef _ASMPOWERPC_SMP_H_
> > > +#define _ASMPOWERPC_SMP_H_
> > > +
> > > +#include <libcflat.h>
> > > +#include <stdint.h>
> > nit: no need to include stdint.h, libcflat.h already does, so most
> > files neglect it.
> Will remove
> >
> > >
> > > +
> > > +typedef void (*secondary_entry_fn)(void);
> > > +
> > > +extern void halt(void);
> > > +
> > > +bool start_thread(int cpu_id, secondary_entry_fn entry, uint32_t
> > > r3);
> > > +bool start_cpu(int cpu_node, secondary_entry_fn entry, uint32_t
> > > r3);
> > > +bool start_all_cpus(secondary_entry_fn entry, uint32_t r3);
> > nit: kvm-unit-tests likes to use 'extern' on function declarations
> Ok, I'll add this
> >
> > >
> > > +
> > > +#endif /* _ASMPOWERPC_SMP_H_ */
> > > diff --git a/lib/powerpc/smp.c b/lib/powerpc/smp.c
> > > new file mode 100644
> > > index 0000000..8968907
> > > --- /dev/null
> > > +++ b/lib/powerpc/smp.c
> > > @@ -0,0 +1,115 @@
> > > +/*
> > > + * Secondary cpu support
> > > + *
> > > + * Copyright 2016 Suraj Jitindar Singh, IBM.
> > > + *
> > > + * This work is licensed under the terms of the GNU LGPL, version
> > > 2.
> > > + */
> > > +
> > > +#include <stdint.h>
> > same nit as above
> >
> > >
> > > +#include <libfdt/libfdt.h>
> > > +#include <libfdt/fdt.h>
> > nit: only need libfdt/libfdt.h, as that includes fdt.h
> >
> > >
> > > +#include <devicetree.h>
> > > +#include <libcflat.h>
> > > +#include <string.h>
> > > +#include <asm/rtas.h>
> > > +#include <asm/smp.h>
> > > +
> > > +struct secondary_entry_data {
> > > + secondary_entry_fn entry;
> > > + uint64_t r3;
> > > + bool init_failed;
> > > +};
> > > +
> > > +/*
> > > + * Start stopped thread cpu_id at entry
> > > + * Returns: 1 on success or cpu not in stopped state
> > > + * 0 on failure to start stopped cpu
> > Returns: TRUE ...
> > FALSE ...
> Same thing, but ok
> >
> > >
> > > + *
> > > + * Note: This function returns 1 on success in starting a stopped
> > > cpu or if the
> > returns true
> >
> > >
> > > + * given cpu was not in the stopped state. Thus this can
> > > be called on a
> > > + * list of cpus and all the stopped ones will be started
> > > while false
> > > + * won't be returned if some cpus in that list were
> > > already running. Thus
> > > + * the user should check that cpus passed to this function
> > > are already in
> > > + * the stopped state if they want to guarantee that a
> > > return value of
> > > + * true corresponds to the given cpu now executing at
> > > entry. This
> > > + * function checks again however as calling cpu-start on a
> > > not stopped
> > > + * cpu results in undefined behaviour.
> > > + */
> > > +bool start_thread(int cpu_id, secondary_entry_fn entry, uint32_t
> > > r3)
> > > +{
> > > + int query_token, start_token, outputs[1], ret;
> > > +
> > > + query_token = rtas_token("query-cpu-stopped-state");
> > > + start_token = rtas_token("start-cpu");
> > > + assert(query_token != RTAS_UNKNOWN_SERVICE &&
> > > + start_token != RTAS_UNKNOWN_SERVICE);
> > > +
> > > + ret = rtas_call(query_token, 1, 2, outputs, cpu_id);
> > > + if (ret) {
> > > + printf("query-cpu-stopped-state failed for cpu
> > > %d\n", cpu_id);
> > > + return false;
> > > + }
> > > +
> > > + if (!outputs[0]) { /* cpu in stopped state */
> > > + ret = rtas_call(start_token, 3, 1, NULL, cpu_id,
> > > entry, r3);
> > > + if (ret) {
> > > + printf("failed to start cpu %d\n",
> > > cpu_id);
> > > + return false;
> > > + }
> > > + }
> > > +
> > > + return true;
> > > +}
> > > +
> > > +/*
> > > + * Start all stopped threads (vcpus) on cpu_node
> > > + * Returns: 1 on success
> > > + * 0 on failure
> > TRUE/FALSE, but I'd actually change the return type to struct
> > start_threads;
> >
> > struct start_threads {
> > int nr_threads;
> > int nr_started;
> > };
> >
> > Then...
> >
> > >
> > > + */
> > > +bool start_cpu(int cpu_node, secondary_entry_fn entry, uint32_t
> > > r3)
> > > +{
> > > + const struct fdt_property *prop;
> > > + int len, nr_cpu, cpu;
> > > + u32 *cpus;
> > > + bool ret = true;
> > > +
> > > + /* Get the id array of threads on this cpu_node */
> > > + prop = fdt_get_property(dt_fdt(), cpu_node,
> > > + "ibm,ppc-interrupt-server#s", &len);
> > > + assert(prop);
> > > +
> > > + nr_cpu = len >> 2; /* Divide by 4 since 4 bytes per cpu */
> > > + cpus = (u32 *)prop->data; /* Array of valid cpu numbers */
> > > +
> > > + for (cpu = 0; cpu < nr_cpu && ret; cpu++)
> > > + ret = start_thread(fdt32_to_cpu(cpus[cpu]), entry,
> > > r3);
> > > + return ret;
> > ...change this to
> >
> > nr_threads = len >> 2; /* Divide by 4 since 4 bytes per cpu */
> > cpus = (u32 *)prop->data; /* Array of valid cpu numbers */
> >
> > for (cpu = 0; cpu < nr_threads; cpu++)
> > nr_started += start_thread(fdt32_to_cpu(cpus[cpu]), entry, r3);
> I guess this fits the more generic use case. Although I can't really
> see a scenario where the caller wants to start all cpus and continue
> starting them when one fails, that is if one fails to start you
> probably might as well return an error code immediately.
> >
> > return (struct start_threads){ nr_threads, nr_started };
> >
> > and...
> >
> > >
> > > +}
> > > +
> > > +static void start_each_secondary(int fdtnode, u32 regval __unused,
> > > void *info)
> > > +{
> > > + struct secondary_entry_data *datap = info;
> > > +
> > > + datap->init_failed |= !start_cpu(fdtnode, datap->entry,
> > > datap->r3);
> > > +}
> > ...change init_failed to nr_started
> >
> > start_threads = start_cpu(fdtnode, datap->entry, datap->r3);
> > nr_cpus += start_threads.nr_threads; // nr_cpus is global like ARM
> > has
> > datap->nr_started += start_threads.nr_started;
> >
> > and below just check that datap->nr_started == nr_cpus.
> nr_cpus is set during setup so it would be possible to just have the
> above return nr_started and then check this accumulated value against
> nr_cpu below.
> >
> > >
> > > +
> > > +/*
> > > + * Start all stopped cpus on the guest at entry with register 3
> > > set to r3
> > > + * Returns: 1 on success
> > > + * 0 on failure
> > TRUE/FALSE
> Ok
> >
> > >
> > > + */
> > > +bool start_all_cpus(secondary_entry_fn entry, uint32_t r3)
> > > +{
> > > + struct secondary_entry_data data = {
> > > + entry,
> > > + r3,
> > > + false
> > > + };
> > > + int ret;
> > > +
> > > + ret = dt_for_each_cpu_node(&start_each_secondary, (void *)
> > > &data);
> > assert(ret == 0)
> Sounds good
> >
> > >
> > > +
> > > + return !(ret || data.init_failed);
> > See comment above about setting nr_cpus, and then just confirming
> > they all
> > started here instead.
> I think I'll change the above so that start_cpu returns the number of
> cpus started (we already know the total number of cpus so the struct is
> unnecessary), we come in with one cpu already started so I'll check
> that nr_started == nr_cpu - 1.
I completely forgot that I wrote code setting up nr_cpus... After
reading this patch, I actually assumed I hadn't, because I didn't
recall addressing threads. So is the nr_cpus in setup correct?
Without accounting for threads, then it can't be, can it? Maybe
this patch series should start by fixing that, and also bumping
NR_CPUS in lib/powerpc/asm/setup.h up to whatever makes more sense.
> >
> > >
> > > +}
> > > diff --git a/lib/ppc64/asm/smp.h b/lib/ppc64/asm/smp.h
> > > new file mode 100644
> > > index 0000000..67ced75
> > > --- /dev/null
> > > +++ b/lib/ppc64/asm/smp.h
> > > @@ -0,0 +1 @@
> > > +#include "../../powerpc/asm/smp.h"
> > > diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common
> > > index 404194b..677030a 100644
> > > --- a/powerpc/Makefile.common
> > > +++ b/powerpc/Makefile.common
> > > @@ -37,6 +37,7 @@ cflatobjs += lib/powerpc/setup.o
> > > cflatobjs += lib/powerpc/rtas.o
> > > cflatobjs += lib/powerpc/processor.o
> > > cflatobjs += lib/powerpc/handlers.o
> > > +cflatobjs += lib/powerpc/smp.o
> > >
> > > FLATLIBS = $(libcflat) $(LIBFDT_archive)
> > > %.elf: CFLAGS += $(arch_CFLAGS)
> Thanks for the review
Thanks,
drew
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