Re: [Qemu-devel] [PATCH v5 2/5] hpet: entitle more irq pins for hpet

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Sep 30, 2013 at 04:02:29PM +0800, liu ping fan wrote:
> On Sun, Sep 29, 2013 at 12:15 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> > On Sun, Sep 29, 2013 at 11:49:41AM +0800, liu ping fan wrote:
> >> On Sun, Sep 29, 2013 at 3:56 AM, Michael S. Tsirkin <mst@redhat.com> wrote:
> >> > On Thu, Sep 12, 2013 at 11:25:15AM +0800, Liu Ping Fan wrote:
> >> >> On PC, IRQ2/8 can be reserved for hpet timer 0/1. And pin 16~23
> >> >> of ioapic can be dynamically assigned to hpet as guest chooses.
> >> >> (Will enable them after introducing pc 1.6 compat)
> >> >>
> >> >> Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
> >> >> ---
> >> >>  hw/timer/hpet.c | 13 +++++++++++--
> >> >>  1 file changed, 11 insertions(+), 2 deletions(-)
> >> >>
> >> >> diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
> >> >> index 8429eb3..46903b9 100644
> >> >> --- a/hw/timer/hpet.c
> >> >> +++ b/hw/timer/hpet.c
> >> >> @@ -25,6 +25,7 @@
> >> >>   */
> >> >>
> >> >>  #include "hw/hw.h"
> >> >> +#include "hw/boards.h"
> >> >>  #include "hw/i386/pc.h"
> >> >>  #include "ui/console.h"
> >> >>  #include "qemu/timer.h"
> >> >> @@ -42,6 +43,12 @@
> >> >>
> >> >>  #define HPET_MSI_SUPPORT        0
> >> >>
> >> >> +/* For bug compat, using only IRQ2. Soon it will be fixed as
> >> >> + * 0xff0104ULL, i.e using IRQ16~23, IRQ8 and IRQ2
> >> >
> >> > So users are expected to stick a bitmask of legal
> >> > pins here?
> >> > I think that's a bit too much rope to give to users.
> >> > Don't you think?
> >> >
> >> Sorry, not understand your meaning exactly.  But the scene will be:
> >> guest kernel polls the ability bitmask, and pick up one pin which is
> >> not occupied or can be shared with the level-trigger and low-active.
> >> So is it rope?
> >
> > I merely say that it's better to make this a bool or bit property.
> > UINT32 is too much flexibility imho.
> >
> The interrupt capability is export to guest by register
> Tn_INT_ROUTE_CAP[63:32]. So it is useless to make them as a bit
> property. Do you think so?
> 
> Regards
> Pingfan

I think we merely need to support two modes:
- qemu 1.6 and older compatible
- compatible to actual hardware

Why would we let users configure an arbitrary
configuration which isn't compatible to either
old qemu or real hardware?


> config register in hpet con
> >> Thanks and regards,
> >> Pingfan
> >> >> after
> >> >> + * introducing pc-1.6 compat.
> >> >> + */
> >> >> +#define HPET_TN_INT_CAP_DEFAULT 0x4ULL
> >> >> +
> >> >>  #define TYPE_HPET "hpet"
> >> >>  #define HPET(obj) OBJECT_CHECK(HPETState, (obj), TYPE_HPET)
> >> >>
> >> >> @@ -73,6 +80,7 @@ typedef struct HPETState {
> >> >>      uint8_t rtc_irq_level;
> >> >>      qemu_irq pit_enabled;
> >> >>      uint8_t num_timers;
> >> >> +    uint32_t intcap;
> >> >>      HPETTimer timer[HPET_MAX_TIMERS];
> >> >>
> >> >>      /* Memory-mapped, software visible registers */
> >> >> @@ -663,8 +671,8 @@ static void hpet_reset(DeviceState *d)
> >> >>          if (s->flags & (1 << HPET_MSI_SUPPORT)) {
> >> >>              timer->config |= HPET_TN_FSB_CAP;
> >> >>          }
> >> >> -        /* advertise availability of ioapic inti2 */
> >> >> -        timer->config |=  0x00000004ULL << 32;
> >> >> +        /* advertise availability of ioapic int */
> >> >> +        timer->config |=  (uint64_t)s->intcap << 32;
> >> >>          timer->period = 0ULL;
> >> >>          timer->wrap_flag = 0;
> >> >>      }
> >> >> @@ -753,6 +761,7 @@ static void hpet_realize(DeviceState *dev, Error **errp)
> >> >>  static Property hpet_device_properties[] = {
> >> >>      DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
> >> >>      DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
> >> >> +    DEFINE_PROP_UINT32("intcap", HPETState, intcap, HPET_TN_INT_CAP_DEFAULT),
> >> >>      DEFINE_PROP_END_OF_LIST(),
> >> >>  };
> >> >>
> >> >> --
> >> >> 1.8.1.4
> >> >>