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Re: [Qemu-arm] [Qemu-devel] [kvm-unit-tests PATCH v3 09/10] arm/arm64: g


From: Andrew Jones
Subject: Re: [Qemu-arm] [Qemu-devel] [kvm-unit-tests PATCH v3 09/10] arm/arm64: gicv3: add an IPI test
Date: Mon, 17 Oct 2016 15:36:09 +0200
User-agent: Mutt/1.6.0.1 (2016-04-01)

On Thu, Sep 01, 2016 at 06:42:44PM +0200, Auger Eric wrote:
> Hi Drew,
> 
> On 15/07/2016 15:00, Andrew Jones wrote:
> > Signed-off-by: Andrew Jones <address@hidden>
> > 
> > ---
> > v2: use IRM for gicv3 broadcast
> > ---
> >  arm/gic.c         | 157 
> > ++++++++++++++++++++++++++++++++++++++++++++++++++----
> >  arm/unittests.cfg |   6 +++
> >  2 files changed, 154 insertions(+), 9 deletions(-)
> > 
> > diff --git a/arm/gic.c b/arm/gic.c
> > index cf7ec1c90413c..fc7ef241de3e2 100644
> > --- a/arm/gic.c
> > +++ b/arm/gic.c
> > @@ -3,6 +3,8 @@
> >   *
> >   * GICv2
> >   *   . test sending/receiving IPIs
> > + * GICv3
> > + *   . test sending/receiving IPIs
> >   *
> >   * Copyright (C) 2016, Red Hat Inc, Andrew Jones <address@hidden>
> >   *
> > @@ -16,6 +18,18 @@
> >  #include <asm/barrier.h>
> >  #include <asm/io.h>
> >  
> > +struct gic {
> > +   struct {
> > +           void (*enable)(void);
> > +           void (*send_self)(void);
> > +           void (*send_tlist)(cpumask_t *);
> > +           void (*send_broadcast)(void);
> > +   } ipi;
> > +   u32 (*read_iar)(void);
> > +   void (*write_eoi)(u32);
> > +};
> > +
> > +static struct gic *gic;
> >  static int gic_version;
> >  static int acked[NR_CPUS], spurious[NR_CPUS];
> >  static cpumask_t ready;
> > @@ -69,12 +83,22 @@ static void check_acked(cpumask_t *mask)
> >            false, missing, extra, unexpected);
> >  }
> >  
> > +static u32 gicv2_read_iar(void)
> > +{
> > +   return readl(gicv2_cpu_base() + GIC_CPU_INTACK);
> > +}
> > +
> > +static void gicv2_write_eoi(u32 irq)
> > +{
> > +   writel(irq, gicv2_cpu_base() + GIC_CPU_EOI);
> > +}
> > +
> >  static void ipi_handler(struct pt_regs *regs __unused)
> >  {
> > -   u32 iar = readl(gicv2_cpu_base() + GIC_CPU_INTACK);
> > +   u32 iar = gic->read_iar();
> >  
> >     if (iar != GICC_INT_SPURIOUS) {
> > -           writel(iar, gicv2_cpu_base() + GIC_CPU_EOI);
> > +           gic->write_eoi(iar);
> >             smp_rmb(); /* pairs with wmb in ipi_test functions */
> >             ++acked[smp_processor_id()];
> >             smp_wmb(); /* pairs with rmb in check_acked */
> > @@ -84,6 +108,89 @@ static void ipi_handler(struct pt_regs *regs __unused)
> >     }
> >  }
> >  
> > +static void gicv2_ipi_send_self(void)
> > +{
> > +   writel(2 << 24, gicv2_dist_base() + GIC_DIST_SOFTINT);
> > +}
> > +
> > +static void gicv2_ipi_send_tlist(cpumask_t *mask)
> > +{
> > +   u8 tlist = (u8)cpumask_bits(mask)[0];
> > +
> > +   writel(tlist << 16, gicv2_dist_base() + GIC_DIST_SOFTINT);
> > +}
> > +
> > +static void gicv2_ipi_send_broadcast(void)
> > +{
> > +   writel(1 << 24, gicv2_dist_base() + GIC_DIST_SOFTINT);
> > +}
> > +
> > +#define ICC_SGI1R_AFFINITY_1_SHIFT 16
> > +#define ICC_SGI1R_AFFINITY_2_SHIFT 32
> > +#define ICC_SGI1R_AFFINITY_3_SHIFT 48
> > +#define MPIDR_TO_SGI_AFFINITY(cluster_id, level) \
> > +   (MPIDR_AFFINITY_LEVEL(cluster_id, level) << ICC_SGI1R_AFFINITY_## level 
> > ## _SHIFT)
> > +
> > +static void gicv3_ipi_send_tlist(cpumask_t *mask)
> > +{
> This function really is indigestible to me. Can't we reuse the linux
> kernel gic_compute_target_list routine. Since the code looks similar why
> not trying to be as close as possible to the kernel?

It is the same, but simplified :-) In Linux, gic_compute_target_list is
not the only function you need for the implementation. You also need to
look at the one caller, which is gic_raise_softirq. I'll add a couple of
comments to this version, which simply inlines the kernel's version.

Thanks,
drew 

> 
> Thanks
> 
> Eric
> > +   u16 tlist;
> > +   int cpu;
> > +
> > +   for_each_cpu(cpu, mask) {
> > +           u64 mpidr = cpus[cpu], sgi1r;
> > +           u64 cluster_id = mpidr & ~0xffUL;
> > +
> > +           tlist = 0;
> > +
> > +           while (cpu < nr_cpus) {
> > +                   if ((mpidr & 0xff) >= 16) {
> > +                           printf("cpu%d MPIDR:aff0 is %d (>= 16)!\n",
> > +                                   cpu, (int)(mpidr & 0xff));
> > +                           break;
> > +                   }
> > +
> > +                   tlist |= 1 << (mpidr & 0xf);
> > +
> > +                   cpu = cpumask_next(cpu, mask);
> > +                   if (cpu >= nr_cpus)
> > +                           break;
> > +
> > +                   mpidr = cpus[cpu];
> > +
> > +                   if (cluster_id != (mpidr & ~0xffUL)) {
> > +                           --cpu;
> > +                           break;
> > +                   }
> > +           }
> > +
> > +           sgi1r = (MPIDR_TO_SGI_AFFINITY(cluster_id, 3)   |
> > +                    MPIDR_TO_SGI_AFFINITY(cluster_id, 2)   |
> > +                    /* irq << 24                           | */
> > +                    MPIDR_TO_SGI_AFFINITY(cluster_id, 1)   |
> > +                    tlist);
> > +
> > +           gicv3_write_sgi1r(sgi1r);
> > +   }
> > +
> > +   /* Force the above writes to ICC_SGI1R_EL1 to be executed */
> > +   isb();
> > +}
> > +
> > +static void gicv3_ipi_send_self(void)
> > +{
> > +   cpumask_t mask;
> > +
> > +   cpumask_clear(&mask);
> > +   cpumask_set_cpu(smp_processor_id(), &mask);
> > +   gicv3_ipi_send_tlist(&mask);
> > +}
> > +
> > +static void gicv3_ipi_send_broadcast(void)
> > +{
> > +   gicv3_write_sgi1r(1ULL << 40);
> > +   isb();
> > +}
> > +
> >  static void ipi_test_self(void)
> >  {
> >     cpumask_t mask;
> > @@ -93,7 +200,7 @@ static void ipi_test_self(void)
> >     smp_wmb();
> >     cpumask_clear(&mask);
> >     cpumask_set_cpu(0, &mask);
> > -   writel(2 << 24, gicv2_dist_base() + GIC_DIST_SOFTINT);
> > +   gic->ipi.send_self();
> >     check_acked(&mask);
> >     report_prefix_pop();
> >  }
> > @@ -101,14 +208,15 @@ static void ipi_test_self(void)
> >  static void ipi_test_smp(void)
> >  {
> >     cpumask_t mask;
> > -   unsigned long tlist;
> > +   int i;
> >  
> >     report_prefix_push("target-list");
> >     memset(acked, 0, sizeof(acked));
> >     smp_wmb();
> > -   tlist = cpumask_bits(&cpu_present_mask)[0] & 0xaa;
> > -   cpumask_bits(&mask)[0] = tlist;
> > -   writel((u8)tlist << 16, gicv2_dist_base() + GIC_DIST_SOFTINT);
> > +   cpumask_copy(&mask, &cpu_present_mask);
> > +   for (i = 0; i < nr_cpus; i += 2)
> > +           cpumask_clear_cpu(i, &mask);
> > +   gic->ipi.send_tlist(&mask);
> >     check_acked(&mask);
> >     report_prefix_pop();
> >  
> > @@ -117,14 +225,14 @@ static void ipi_test_smp(void)
> >     smp_wmb();
> >     cpumask_copy(&mask, &cpu_present_mask);
> >     cpumask_clear_cpu(0, &mask);
> > -   writel(1 << 24, gicv2_dist_base() + GIC_DIST_SOFTINT);
> > +   gic->ipi.send_broadcast();
> >     check_acked(&mask);
> >     report_prefix_pop();
> >  }
> >  
> >  static void ipi_enable(void)
> >  {
> > -   gicv2_enable_defaults();
> > +   gic->ipi.enable();
> >  #ifdef __arm__
> >     install_exception_handler(EXCPTN_IRQ, ipi_handler);
> >  #else
> > @@ -141,6 +249,28 @@ static void ipi_recv(void)
> >             wfi();
> >  }
> >  
> > +struct gic gicv2 = {
> > +   .ipi = {
> > +           .enable = gicv2_enable_defaults,
> > +           .send_self = gicv2_ipi_send_self,
> > +           .send_tlist = gicv2_ipi_send_tlist,
> > +           .send_broadcast = gicv2_ipi_send_broadcast,
> > +   },
> > +   .read_iar = gicv2_read_iar,
> > +   .write_eoi = gicv2_write_eoi,
> > +};
> > +
> > +struct gic gicv3 = {
> > +   .ipi = {
> > +           .enable = gicv3_enable_defaults,
> > +           .send_self = gicv3_ipi_send_self,
> > +           .send_tlist = gicv3_ipi_send_tlist,
> > +           .send_broadcast = gicv3_ipi_send_broadcast,
> > +   },
> > +   .read_iar = gicv3_read_iar,
> > +   .write_eoi = gicv3_write_eoir,
> > +};
> > +
> >  int main(int argc, char **argv)
> >  {
> >     char pfx[8];
> > @@ -153,6 +283,15 @@ int main(int argc, char **argv)
> >     snprintf(pfx, 8, "gicv%d", gic_version);
> >     report_prefix_push(pfx);
> >  
> > +   switch (gic_version) {
> > +   case 2:
> > +           gic = &gicv2;
> > +           break;
> > +   case 3:
> > +           gic = &gicv3;
> > +           break;
> > +   }
> > +
> >     if (argc < 2) {
> >  
> >             report_prefix_push("ipi");
> > diff --git a/arm/unittests.cfg b/arm/unittests.cfg
> > index bb364675043f0..043a20e26e98c 100644
> > --- a/arm/unittests.cfg
> > +++ b/arm/unittests.cfg
> > @@ -58,3 +58,9 @@ file = gic.flat
> >  smp = $((($MAX_SMP < 8)?$MAX_SMP:8))
> >  extra_params = -machine gic-version=2 -append 'ipi'
> >  groups = gic
> > +
> > +[gicv3-ipi]
> > +file = gic.flat
> > +smp = $MAX_SMP
> > +extra_params = -machine gic-version=3 -append 'ipi'
> > +groups = gic
> > 
> 



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