src/patches/60020_746-pirq-status-page.patch1

   1 From: http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/d545a95fca73
   2 # HG changeset 746+749 patch
   3 # User Keir Fraser <keir.fraser@citrix.com>
   4 # Date 1227879027 0
   5 # Node ID d545a95fca739d0b1963b73a9eb64ea64a244e76
   6 # Parent  2268be46c75ec6eddb7cd387af8a236a565f6140
   7 Subject: linux/x86: use shared page indicating the need for an EOI notification
   8 Patch-mainline: obsolete
   9
  10 Signed-off-by: Jan Beulich <jbeulich@novell.com>
  11
  12 From: http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/cdc6729dc702
  13 Subject: evtchn: Fix the build.
  14 Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
  15
  16 Index: head-2008-12-01/drivers/xen/core/evtchn.c
  17 ===================================================================
  18 --- head-2008-12-01.orig/drivers/xen/core/evtchn.c      2008-12-01 11:22:35.000000000 +0100
  19 +++ head-2008-12-01/drivers/xen/core/evtchn.c   2008-12-01 11:23:06.000000000 +0100
  20 @@ -123,9 +123,6 @@ DEFINE_PER_CPU(int, ipi_to_irq[NR_IPIS])
  21  /* Reference counts for bindings to IRQs. */
  22  static int irq_bindcount[NR_IRQS];
  23
  24 -/* Bitmap indicating which PIRQs require Xen to be notified on unmask. */
  25 -static DECLARE_BITMAP(pirq_needs_eoi, NR_PIRQS);
  26 -
  27  #ifdef CONFIG_SMP
  28
  29  static u8 cpu_evtchn[NR_EVENT_CHANNELS];
  30 @@ -756,16 +753,48 @@ static struct hw_interrupt_type dynirq_t
  31         .retrigger = resend_irq_on_evtchn,
  32  };
  33
  34 -static inline void pirq_unmask_notify(int irq)
  35 +/* Bitmap indicating which PIRQs require Xen to be notified on unmask. */
  36 +static int pirq_eoi_does_unmask;
  37 +static DECLARE_BITMAP(pirq_needs_eoi, ALIGN(NR_PIRQS, PAGE_SIZE * 8))
  38 +       __attribute__ ((__section__(".bss.page_aligned"), __aligned__(PAGE_SIZE)));
  39 +
  40 +static void pirq_unmask_and_notify(unsigned int evtchn, unsigned int irq)
  41  {
  42         struct physdev_eoi eoi = { .irq = evtchn_get_xen_pirq(irq) };
  43 -       if (unlikely(test_bit(irq - PIRQ_BASE, pirq_needs_eoi)))
  44 -               VOID(HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi));
  45 +
  46 +       if (pirq_eoi_does_unmask) {
  47 +               if (test_bit(eoi.irq, pirq_needs_eoi))
  48 +                       VOID(HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi));
  49 +               else
  50 +                       unmask_evtchn(evtchn);
  51 +       } else if (test_bit(irq - PIRQ_BASE, pirq_needs_eoi)) {
  52 +               if (smp_processor_id() != cpu_from_evtchn(evtchn)) {
  53 +                       struct evtchn_unmask unmask = { .port = evtchn };
  54 +                       struct multicall_entry mcl[2];
  55 +
  56 +                       mcl[0].op = __HYPERVISOR_event_channel_op;
  57 +                       mcl[0].args[0] = EVTCHNOP_unmask;
  58 +                       mcl[0].args[1] = (unsigned long)&unmask;
  59 +                       mcl[1].op = __HYPERVISOR_physdev_op;
  60 +                       mcl[1].args[0] = PHYSDEVOP_eoi;
  61 +                       mcl[1].args[1] = (unsigned long)&eoi;
  62 +
  63 +                       if (HYPERVISOR_multicall(mcl, 2))
  64 +                               BUG();
  65 +               } else {
  66 +                       unmask_evtchn(evtchn);
  67 +                       VOID(HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi));
  68 +               }
  69 +       } else
  70 +               unmask_evtchn(evtchn);
  71  }
  72
  73  static inline void pirq_query_unmask(int irq)
  74  {
  75         struct physdev_irq_status_query irq_status;
  76 +
  77 +       if (pirq_eoi_does_unmask)
  78 +               return;
  79         irq_status.irq = evtchn_get_xen_pirq(irq);
  80         if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
  81                 irq_status.flags = 0;
  82 @@ -806,8 +835,7 @@ static unsigned int startup_pirq(unsigne
  83         irq_info[irq] = mk_irq_info(IRQT_PIRQ, bind_pirq.pirq, evtchn);
  84
  85   out:
  86 -       unmask_evtchn(evtchn);
  87 -       pirq_unmask_notify(irq);
  88 +       pirq_unmask_and_notify(evtchn, irq);
  89
  90         return 0;
  91  }
  92 @@ -859,10 +887,8 @@ static void end_pirq(unsigned int irq)
  93         if ((irq_desc[irq].status & (IRQ_DISABLED|IRQ_PENDING)) ==
  94             (IRQ_DISABLED|IRQ_PENDING)) {
  95                 shutdown_pirq(irq);
  96 -       } else if (VALID_EVTCHN(evtchn)) {
  97 -               unmask_evtchn(evtchn);
  98 -               pirq_unmask_notify(irq);
  99 -       }
 100 +       } else if (VALID_EVTCHN(evtchn))
 101 +               pirq_unmask_and_notify(evtchn, irq);
 102  }
 103
 104  static struct hw_interrupt_type pirq_type = {
 105 @@ -1012,6 +1038,14 @@ void irq_resume(void)
 106
 107         init_evtchn_cpu_bindings();
 108
 109 +       if (pirq_eoi_does_unmask) {
 110 +               struct physdev_pirq_eoi_mfn eoi_mfn;
 111 +
 112 +               eoi_mfn.mfn = virt_to_bus(pirq_needs_eoi) >> PAGE_SHIFT;
 113 +               if (HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_mfn, &eoi_mfn))
 114 +                       BUG();
 115 +       }
 116 +
 117         /* New event-channel space is not 'live' yet. */
 118         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 119                 mask_evtchn(evtchn);
 120 @@ -1098,9 +1132,15 @@ int evtchn_get_xen_pirq(int irq)
 121  void __init xen_init_IRQ(void)
 122  {
 123         unsigned int i;
 124 +       struct physdev_pirq_eoi_mfn eoi_mfn;
 125
 126         init_evtchn_cpu_bindings();
 127
 128 +       BUG_ON(!bitmap_empty(pirq_needs_eoi, PAGE_SIZE * 8));
 129 +       eoi_mfn.mfn = virt_to_bus(pirq_needs_eoi) >> PAGE_SHIFT;
 130 +       if (HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_mfn, &eoi_mfn) == 0)
 131 +               pirq_eoi_does_unmask = 1;
 132 +
 133         /* No event channels are 'live' right now. */
 134         for (i = 0; i < NR_EVENT_CHANNELS; i++)
 135                 mask_evtchn(i);
 136 Index: head-2008-12-01/include/xen/interface/physdev.h
 137 ===================================================================
 138 --- head-2008-12-01.orig/include/xen/interface/physdev.h        2008-12-01 11:22:59.000000000 +0100
 139 +++ head-2008-12-01/include/xen/interface/physdev.h     2008-12-01 11:23:06.000000000 +0100
 140 @@ -41,6 +41,21 @@ typedef struct physdev_eoi physdev_eoi_t
 141  DEFINE_XEN_GUEST_HANDLE(physdev_eoi_t);
 142
 143  /*
 144 + * Register a shared page for the hypervisor to indicate whether the guest
 145 + * must issue PHYSDEVOP_eoi. The semantics of PHYSDEVOP_eoi change slightly
 146 + * once the guest used this function in that the associated event channel
 147 + * will automatically get unmasked. The page registered is used as a bit
 148 + * array indexed by Xen's PIRQ value.
 149 + */
 150 +#define PHYSDEVOP_pirq_eoi_mfn          17
 151 +struct physdev_pirq_eoi_mfn {
 152 +    /* IN */
 153 +    xen_pfn_t mfn;
 154 +};
 155 +typedef struct physdev_pirq_eoi_mfn physdev_pirq_eoi_mfn_t;
 156 +DEFINE_XEN_GUEST_HANDLE(physdev_pirq_eoi_mfn_t);
 157 +
 158 +/*
 159   * Query the status of an IRQ line.
 160   * @arg == pointer to physdev_irq_status_query structure.
 161   */