Re: [Qemu-devel] [PATCH v5 08/16] spapr_events: re-use EPOW event infrastructure for hotplug events

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting David Gibson (2015-02-24 00:49:42)
> On Mon, Feb 16, 2015 at 08:27:44AM -0600, Michael Roth wrote:
> > From: Nathan Fontenot <nfont@linux.vnet.ibm.com>
> > 
> > This extends the data structures currently used to report EPOW events to
> > guests via the check-exception RTAS interfaces to also include event types
> > for hotplug/unplug events.
> > 
> > This is currently undocumented and being finalized for inclusion in PAPR
> > specification, but we implement this here as an extension for guest
> > userspace tools to implement (existing guest kernels simply log these
> > events via a sysfs interface that's read by rtas_errd, and current
> > versions of rtas_errd/powerpc-utils already support the use of this
> > mechanism for initiating hotplug operations).
> > 
> > We also add support for queues of pending RTAS events, since in the
> > case of hotplug there's chance for multiple events being in-flight
> > at any point in time.
> > 
> > Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
> > Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> > ---
> >  hw/ppc/spapr.c         |   2 +-
> >  hw/ppc/spapr_events.c  | 271 ++++++++++++++++++++++++++++++++++++++++---------
> >  include/hw/ppc/spapr.h |   5 +-
> >  3 files changed, 226 insertions(+), 52 deletions(-)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index bfacc9d..861107e 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -1640,7 +1640,7 @@ static void ppc_spapr_init(MachineState *machine)
> >      spapr->fdt_skel = spapr_create_fdt_skel(initrd_base, initrd_size,
> >                                              kernel_size, kernel_le,
> >                                              boot_device, kernel_cmdline,
> > -                                            spapr->epow_irq);
> > +                                            spapr->check_exception_irq);
> >      assert(spapr->fdt_skel != NULL);
> >  }
> >  
> > diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
> > index 283e96b..0eeb1d8 100644
> > --- a/hw/ppc/spapr_events.c
> > +++ b/hw/ppc/spapr_events.c
> > @@ -32,6 +32,9 @@
> >  
> >  #include "hw/ppc/spapr.h"
> >  #include "hw/ppc/spapr_vio.h"
> > +#include "hw/pci/pci.h"
> > +#include "hw/pci-host/spapr.h"
> > +#include "hw/ppc/spapr_drc.h"
> >  
> >  #include <libfdt.h>
> >  
> > @@ -77,6 +80,7 @@ struct rtas_error_log {
> >  #define   RTAS_LOG_TYPE_ECC_UNCORR              0x00000009
> >  #define   RTAS_LOG_TYPE_ECC_CORR                0x0000000a
> >  #define   RTAS_LOG_TYPE_EPOW                    0x00000040
> > +#define   RTAS_LOG_TYPE_HOTPLUG                 0x000000e5
> >      uint32_t extended_length;
> >  } QEMU_PACKED;
> >  
> > @@ -166,6 +170,38 @@ struct epow_log_full {
> >      struct rtas_event_log_v6_epow epow;
> >  } QEMU_PACKED;
> >  
> > +struct rtas_event_log_v6_hp {
> > +#define RTAS_LOG_V6_SECTION_ID_HOTPLUG              0x4850 /* HP */
> > +    struct rtas_event_log_v6_section_header hdr;
> > +    uint8_t hotplug_type;
> > +#define RTAS_LOG_V6_HP_TYPE_CPU                          1
> > +#define RTAS_LOG_V6_HP_TYPE_MEMORY                       2
> > +#define RTAS_LOG_V6_HP_TYPE_SLOT                         3
> > +#define RTAS_LOG_V6_HP_TYPE_PHB                          4
> > +#define RTAS_LOG_V6_HP_TYPE_PCI                          5
> > +    uint8_t hotplug_action;
> > +#define RTAS_LOG_V6_HP_ACTION_ADD                        1
> > +#define RTAS_LOG_V6_HP_ACTION_REMOVE                     2
> > +    uint8_t hotplug_identifier;
> > +#define RTAS_LOG_V6_HP_ID_DRC_NAME                       1
> > +#define RTAS_LOG_V6_HP_ID_DRC_INDEX                      2
> > +#define RTAS_LOG_V6_HP_ID_DRC_COUNT                      3
> > +    uint8_t reserved;
> > +    union {
> > +        uint32_t index;
> > +        uint32_t count;
> > +        char name[1];
> > +    } drc;
> > +} QEMU_PACKED;
> > +
> > +struct hp_log_full {
> > +    struct rtas_error_log hdr;
> > +    struct rtas_event_log_v6 v6hdr;
> > +    struct rtas_event_log_v6_maina maina;
> > +    struct rtas_event_log_v6_mainb mainb;
> > +    struct rtas_event_log_v6_hp hp;
> > +} QEMU_PACKED;
> > +
> >  #define EVENT_MASK_INTERNAL_ERRORS           0x80000000
> >  #define EVENT_MASK_EPOW                      0x40000000
> >  #define EVENT_MASK_HOTPLUG                   0x10000000
> > @@ -181,67 +217,84 @@ struct epow_log_full {
> >          }                                                          \
> >      } while (0)
> >  
> > -void spapr_events_fdt_skel(void *fdt, uint32_t epow_irq)
> > +void spapr_events_fdt_skel(void *fdt, uint32_t check_exception_irq)
> >  {
> > -    uint32_t epow_irq_ranges[] = {cpu_to_be32(epow_irq), cpu_to_be32(1)};
> > -    uint32_t epow_interrupts[] = {cpu_to_be32(epow_irq), 0};
> > +    uint32_t irq_ranges[] = {cpu_to_be32(check_exception_irq), cpu_to_be32(1)};
> > +    uint32_t interrupts[] = {cpu_to_be32(check_exception_irq), 0};
> >  
> >      _FDT((fdt_begin_node(fdt, "event-sources")));
> >  
> >      _FDT((fdt_property(fdt, "interrupt-controller", NULL, 0)));
> >      _FDT((fdt_property_cell(fdt, "#interrupt-cells", 2)));
> >      _FDT((fdt_property(fdt, "interrupt-ranges",
> > -                       epow_irq_ranges, sizeof(epow_irq_ranges))));
> > +                       irq_ranges, sizeof(irq_ranges))));
> >  
> >      _FDT((fdt_begin_node(fdt, "epow-events")));
> > -    _FDT((fdt_property(fdt, "interrupts",
> > -                       epow_interrupts, sizeof(epow_interrupts))));
> > +    _FDT((fdt_property(fdt, "interrupts", interrupts, sizeof(interrupts))));
> >      _FDT((fdt_end_node(fdt)));
> >  
> >      _FDT((fdt_end_node(fdt)));
> >  }
> >  
> > -static struct epow_log_full *pending_epow;
> > -static uint32_t next_plid;
> > +typedef struct EventLogEntry {
> > +    int log_type;
> > +    void *data;
> > +    QTAILQ_ENTRY(EventLogEntry) next;
> > +} EventLogEntry;
> >  
> > -static void spapr_powerdown_req(Notifier *n, void *opaque)
> > +static struct {
> > +    QTAILQ_HEAD(, EventLogEntry) pending_events;
> > +} rtas_event_log;
> 
> Adding new globals is never nice.  Couldn't this go into
> sPAPREnvironment, or better yet the SPAPR_MACHINE structure?  (I'd
> like to merge those two when we get the chance).

Makes sense, will roll into sPAPREnvironment initially

> 
> > +static void rtas_event_log_queue(int log_type, void *data)
> >  {
> > -    sPAPREnvironment *spapr = container_of(n, sPAPREnvironment, epow_notifier);
> > -    struct rtas_error_log *hdr;
> > -    struct rtas_event_log_v6 *v6hdr;
> > -    struct rtas_event_log_v6_maina *maina;
> > -    struct rtas_event_log_v6_mainb *mainb;
> > -    struct rtas_event_log_v6_epow *epow;
> > -    struct tm tm;
> > -    int year;
> > +    EventLogEntry *entry = g_new(EventLogEntry, 1);
> > +
> > +    entry->log_type = log_type;
> > +    entry->data = data;
> > +    QTAILQ_INSERT_TAIL(&rtas_event_log.pending_events, entry, next);
> > +}
> >  
> > -    if (pending_epow) {
> > -        /* For now, we just throw away earlier events if two come
> > -         * along before any are consumed.  This is sufficient for our
> > -         * powerdown messages, but we'll need more if we do more
> > -         * general error/event logging */
> > -        g_free(pending_epow);
> > +static EventLogEntry *rtas_event_log_dequeue(uint32_t event_mask)
> > +{
> > +    EventLogEntry *entry = NULL;
> > +
> > +    /* we only queue EPOW events atm. */
> > +    if ((event_mask & EVENT_MASK_EPOW) == 0) {
> > +        return NULL;
> >      }
> > -    pending_epow = g_malloc0(sizeof(*pending_epow));
> > -    hdr = &pending_epow->hdr;
> > -    v6hdr = &pending_epow->v6hdr;
> > -    maina = &pending_epow->maina;
> > -    mainb = &pending_epow->mainb;
> > -    epow = &pending_epow->epow;
> >  
> > -    hdr->summary = cpu_to_be32(RTAS_LOG_VERSION_6
> > -                               | RTAS_LOG_SEVERITY_EVENT
> > -                               | RTAS_LOG_DISPOSITION_NOT_RECOVERED
> > -                               | RTAS_LOG_OPTIONAL_PART_PRESENT
> > -                               | RTAS_LOG_TYPE_EPOW);
> > -    hdr->extended_length = cpu_to_be32(sizeof(*pending_epow)
> > -                                       - sizeof(pending_epow->hdr));
> > +    QTAILQ_FOREACH(entry, &rtas_event_log.pending_events, next) {
> > +        /* EPOW and hotplug events are surfaced in the same manner */
> > +        if (entry->log_type == RTAS_LOG_TYPE_EPOW ||
> > +            entry->log_type == RTAS_LOG_TYPE_HOTPLUG) {
> > +            break;
> > +        }
> > +    }
> > +
> > +    if (entry) {
> > +        QTAILQ_REMOVE(&rtas_event_log.pending_events, entry, next);
> > +    }
> >  
> > +    return entry;
> > +}
> > +
> > +static uint32_t next_plid;
> > +
> > +static void spapr_init_v6hdr(struct rtas_event_log_v6 *v6hdr)
> > +{
> >      v6hdr->b0 = RTAS_LOG_V6_B0_VALID | RTAS_LOG_V6_B0_NEW_LOG
> >          | RTAS_LOG_V6_B0_BIGENDIAN;
> >      v6hdr->b2 = RTAS_LOG_V6_B2_POWERPC_FORMAT
> >          | RTAS_LOG_V6_B2_LOG_FORMAT_PLATFORM_EVENT;
> >      v6hdr->company = cpu_to_be32(RTAS_LOG_V6_COMPANY_IBM);
> > +}
> > +
> > +static void spapr_init_maina(struct rtas_event_log_v6_maina *maina,
> > +                             int section_count)
> > +{
> > +    struct tm tm;
> > +    int year;
> >  
> >      maina->hdr.section_id = cpu_to_be16(RTAS_LOG_V6_SECTION_ID_MAINA);
> >      maina->hdr.section_length = cpu_to_be16(sizeof(*maina));
> > @@ -256,8 +309,37 @@ static void spapr_powerdown_req(Notifier *n, void *opaque)
> >                                         | (to_bcd(tm.tm_min) << 16)
> >                                         | (to_bcd(tm.tm_sec) << 8));
> >      maina->creator_id = 'H'; /* Hypervisor */
> > -    maina->section_count = 3; /* Main-A, Main-B and EPOW */
> > +    maina->section_count = section_count;
> >      maina->plid = next_plid++;
> > +}
> > +
> > +static void spapr_powerdown_req(Notifier *n, void *opaque)
> > +{
> > +    sPAPREnvironment *spapr = container_of(n, sPAPREnvironment, epow_notifier);
> > +    struct rtas_error_log *hdr;
> > +    struct rtas_event_log_v6 *v6hdr;
> > +    struct rtas_event_log_v6_maina *maina;
> > +    struct rtas_event_log_v6_mainb *mainb;
> > +    struct rtas_event_log_v6_epow *epow;
> > +    struct epow_log_full *pending_epow;
> > +
> > +    pending_epow = g_malloc0(sizeof(*pending_epow));
> 
> The name's no longer really right as a local.
> 
> > +    hdr = &pending_epow->hdr;
> > +    v6hdr = &pending_epow->v6hdr;
> > +    maina = &pending_epow->maina;
> > +    mainb = &pending_epow->mainb;
> > +    epow = &pending_epow->epow;
> > +
> > +    hdr->summary = cpu_to_be32(RTAS_LOG_VERSION_6
> > +                               | RTAS_LOG_SEVERITY_EVENT
> > +                               | RTAS_LOG_DISPOSITION_NOT_RECOVERED
> > +                               | RTAS_LOG_OPTIONAL_PART_PRESENT
> > +                               | RTAS_LOG_TYPE_EPOW);
> > +    hdr->extended_length = cpu_to_be32(sizeof(*pending_epow)
> > +                                       - sizeof(pending_epow->hdr));
> > +
> > +    spapr_init_v6hdr(v6hdr);
> > +    spapr_init_maina(maina, 3 /* Main-A, Main-B and EPOW */);
> >  
> >      mainb->hdr.section_id = cpu_to_be16(RTAS_LOG_V6_SECTION_ID_MAINB);
> >      mainb->hdr.section_length = cpu_to_be16(sizeof(*mainb));
> > @@ -274,7 +356,78 @@ static void spapr_powerdown_req(Notifier *n, void *opaque)
> >      epow->event_modifier = RTAS_LOG_V6_EPOW_MODIFIER_NORMAL;
> >      epow->extended_modifier = RTAS_LOG_V6_EPOW_XMODIFIER_PARTITION_SPECIFIC;
> >  
> > -    qemu_irq_pulse(xics_get_qirq(spapr->icp, spapr->epow_irq));
> > +    rtas_event_log_queue(RTAS_LOG_TYPE_EPOW, pending_epow);
> > +
> > +    qemu_irq_pulse(xics_get_qirq(spapr->icp, spapr->check_exception_irq));
> 
> Shouldn't the irq pulse go into rtas_event_log_queue()?

It seems maybe it should...

"If a platform chooses to report multiple event or error sources through a
 single interrupt, it must ensure that the interrupt remains asserted
 or is re-asserted until check-exception has been used to process all
 out-standing errors or events for that interrupt."

But another alternative would be to have rtas-check-exception re-pulse if there
are still events present for that particular IRQ. I think I'd prefer this
approach, since it makes it easier to share the queueing functionality with
rtas-event-scan (which relies on polling instead of interrupts)

> 
> > +}
> > +
> > +static void spapr_hotplug_req_event(sPAPRDRConnector *drc, uint8_t hp_action)
> > +{
> > +    struct hp_log_full *new_hp;
> > +    struct rtas_error_log *hdr;
> > +    struct rtas_event_log_v6 *v6hdr;
> > +    struct rtas_event_log_v6_maina *maina;
> > +    struct rtas_event_log_v6_mainb *mainb;
> > +    struct rtas_event_log_v6_hp *hp;
> > +    sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> > +    sPAPRDRConnectorType drc_type = drck->get_type(drc);
> > +
> > +    new_hp = g_malloc0(sizeof(struct hp_log_full));
> > +    hdr = &new_hp->hdr;
> > +    v6hdr = &new_hp->v6hdr;
> > +    maina = &new_hp->maina;
> > +    mainb = &new_hp->mainb;
> > +    hp = &new_hp->hp;
> > +
> > +    hdr->summary = cpu_to_be32(RTAS_LOG_VERSION_6
> > +                               | RTAS_LOG_SEVERITY_EVENT
> > +                               | RTAS_LOG_DISPOSITION_NOT_RECOVERED
> > +                               | RTAS_LOG_OPTIONAL_PART_PRESENT
> > +                               | RTAS_LOG_INITIATOR_HOTPLUG
> > +                               | RTAS_LOG_TYPE_HOTPLUG);
> > +    hdr->extended_length = cpu_to_be32(sizeof(*new_hp)
> > +                                       - sizeof(new_hp->hdr));
> > +
> > +    spapr_init_v6hdr(v6hdr);
> > +    spapr_init_maina(maina, 3 /* Main-A, Main-B, HP */);
> > +
> > +    mainb->hdr.section_id = cpu_to_be16(RTAS_LOG_V6_SECTION_ID_MAINB);
> > +    mainb->hdr.section_length = cpu_to_be16(sizeof(*mainb));
> > +    mainb->subsystem_id = 0x80; /* External environment */
> > +    mainb->event_severity = 0x00; /* Informational / non-error */
> > +    mainb->event_subtype = 0x00; /* Normal shutdown */
> > +
> > +    hp->hdr.section_id = cpu_to_be16(RTAS_LOG_V6_SECTION_ID_HOTPLUG);
> > +    hp->hdr.section_length = cpu_to_be16(sizeof(*hp));
> > +    hp->hdr.section_version = 1; /* includes extended modifier */
> > +    hp->hotplug_action = hp_action;
> > +
> > +
> > +    switch (drc_type) {
> > +    case SPAPR_DR_CONNECTOR_TYPE_PCI:
> > +        hp->drc.index = cpu_to_be32(drck->get_index(drc));
> > +        hp->hotplug_identifier = RTAS_LOG_V6_HP_ID_DRC_INDEX;
> > +        hp->hotplug_type = RTAS_LOG_V6_HP_TYPE_PCI;
> > +        break;
> > +    default:
> > +        /* skip notification for unknown connector types */
> 
> This should be an assert, shouldn't it?  If code is added which can
> fire this for non-PCI types, without the corresponding non-PCI option
> here, you want to catch that.

Agreed, if hotplug events are supported for that resource type, we should be
calling this.

> 
> > +        g_free(new_hp);
> > +        return;
> > +    }
> > +
> > +    rtas_event_log_queue(RTAS_LOG_TYPE_HOTPLUG, new_hp);
> > +
> > +    qemu_irq_pulse(xics_get_qirq(spapr->icp, spapr->check_exception_irq));
> > +}
> > +
> > +void spapr_hotplug_req_add_event(sPAPRDRConnector *drc)
> > +{
> > +    spapr_hotplug_req_event(drc, RTAS_LOG_V6_HP_ACTION_ADD);
> > +}
> > +
> > +void spapr_hotplug_req_remove_event(sPAPRDRConnector *drc)
> > +{
> > +    spapr_hotplug_req_event(drc, RTAS_LOG_V6_HP_ACTION_REMOVE);
> >  }
> >  
> >  static void check_exception(PowerPCCPU *cpu, sPAPREnvironment *spapr,
> > @@ -282,8 +435,9 @@ static void check_exception(PowerPCCPU *cpu, sPAPREnvironment *spapr,
> >                              target_ulong args,
> >                              uint32_t nret, target_ulong rets)
> >  {
> > -    uint32_t mask, buf, len;
> > +    uint32_t mask, buf, len, event_len;
> >      uint64_t xinfo;
> > +    EventLogEntry *event;
> >  
> >      if ((nargs < 6) || (nargs > 7) || nret != 1) {
> >          rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> > @@ -298,23 +452,40 @@ static void check_exception(PowerPCCPU *cpu, sPAPREnvironment *spapr,
> >          xinfo |= (uint64_t)rtas_ld(args, 6) << 32;
> >      }
> >  
> > -    if ((mask & EVENT_MASK_EPOW) && pending_epow) {
> > -        if (sizeof(*pending_epow) < len) {
> > -            len = sizeof(*pending_epow);
> > -        }
> > +    event = rtas_event_log_dequeue(mask);
> > +    if (!event) {
> > +        goto out_no_events;
> > +    }
> >  
> > -        cpu_physical_memory_write(buf, pending_epow, len);
> > -        g_free(pending_epow);
> > -        pending_epow = NULL;
> > -        rtas_st(rets, 0, RTAS_OUT_SUCCESS);
> > -    } else {
> > -        rtas_st(rets, 0, RTAS_OUT_NO_ERRORS_FOUND);
> > +    switch (event->log_type) {
> > +        case RTAS_LOG_TYPE_EPOW:
> > +            event_len = sizeof(struct epow_log_full);
> > +            break;
> > +        case RTAS_LOG_TYPE_HOTPLUG:
> > +            event_len = sizeof(struct hp_log_full);
> > +            break;
> > +        default:
> > +            goto out_no_events;
> 
> Doesn't one of the headers include size information you could use
> here, avoiding the switch?

Looks like hdr->extended_length + sizeof(hdr) should do the trick. Nice!

> 
> >      }
> > +
> > +    if (event_len < len) {
> > +        len = event_len;
> > +    }
> > +
> > +    cpu_physical_memory_write(buf, event->data, len);
> > +    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
> > +    g_free(event->data);
> > +    g_free(event);
> > +    return;
> > +
> > +out_no_events:
> > +    rtas_st(rets, 0, RTAS_OUT_NO_ERRORS_FOUND);
> >  }
> >  
> >  void spapr_events_init(sPAPREnvironment *spapr)
> >  {
> > -    spapr->epow_irq = xics_alloc(spapr->icp, 0, 0, false);
> > +    QTAILQ_INIT(&rtas_event_log.pending_events);
> > +    spapr->check_exception_irq = xics_alloc(spapr->icp, 0, 0, false);
> >      spapr->epow_notifier.notify = spapr_powerdown_req;
> >      qemu_register_powerdown_notifier(&spapr->epow_notifier);
> >      spapr_rtas_register(RTAS_CHECK_EXCEPTION, "check-exception",
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index 3cc4490..1d27708 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -3,6 +3,7 @@
> >  
> >  #include "sysemu/dma.h"
> >  #include "hw/ppc/xics.h"
> > +#include "hw/ppc/spapr_drc.h"
> >  
> >  struct VIOsPAPRBus;
> >  struct sPAPRPHBState;
> > @@ -31,7 +32,7 @@ typedef struct sPAPREnvironment {
> >      struct PPCTimebase tb;
> >      bool has_graphics;
> >  
> > -    uint32_t epow_irq;
> > +    uint32_t check_exception_irq;
> >      Notifier epow_notifier;
> >  
> >      /* Migration state */
> > @@ -498,6 +499,8 @@ int spapr_dma_dt(void *fdt, int node_off, const char *propname,
> >                   uint32_t liobn, uint64_t window, uint32_t size);
> >  int spapr_tcet_dma_dt(void *fdt, int node_off, const char *propname,
> >                        sPAPRTCETable *tcet);
> > +void spapr_hotplug_req_add_event(sPAPRDRConnector *drc);
> > +void spapr_hotplug_req_remove_event(sPAPRDRConnector *drc);
> >  
> >  #define TYPE_SPAPR_RTC "spapr-rtc"
> >  
> 
> -- 
> David Gibson                    | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
>                                 | _way_ _around_!
> http://www.ozlabs.org/~dgibson