Re: [Qemu-ppc] [PATCH v5 01/36] ppc/xive: introduce a XIVE interrupt source model

[Cédric Le Goater]

On 11/23/18 1:31 AM, David Gibson wrote:
> On Thu, Nov 22, 2018 at 08:25:06AM +0100, Cédric Le Goater wrote:
>> On 11/22/18 4:05 AM, David Gibson wrote:
>>> On Fri, Nov 16, 2018 at 11:56:54AM +0100, Cédric Le Goater wrote:
>>>> The first sub-engine of the overall XIVE architecture is the Interrupt
>>>> Virtualization Source Engine (IVSE). An IVSE can be integrated into
>>>> another logic, like in a PCI PHB or in the main interrupt controller
>>>> to manage IPIs.
>>>>
>>>> Each IVSE instance is associated with an Event State Buffer (ESB) that
>>>> contains a two bit state entry for each possible event source. When an
>>>> event is signaled to the IVSE, by MMIO or some other means, the
>>>> associated interrupt state bits are fetched from the ESB and
>>>> modified. Depending on the resulting ESB state, the event is forwarded
>>>> to the IVRE sub-engine of the controller doing the routing.
>>>>
>>>> Each supported ESB entry is associated with either a single or a
>>>> even/odd pair of pages which provides commands to manage the source:
>>>> to EOI, to turn off the source for instance.
>>>>
>>>> On a sPAPR machine, the O/S will obtain the page address of the ESB
>>>> entry associated with a source and its characteristic using the
>>>> H_INT_GET_SOURCE_INFO hcall. On PowerNV, a similar OPAL call is used.
>>>>
>>>> The xive_source_notify() routine is in charge forwarding the source
>>>> event notification to the routing engine. It will be filled later on.
>>>>
>>>> Signed-off-by: Cédric Le Goater <address@hidden>
>>>
>>> Ok, this is looking basically pretty good.  Few details to query
>>> below.
>>>
>>>
>>>> ---
>>>>  default-configs/ppc64-softmmu.mak |   1 +
>>>>  include/hw/ppc/xive.h             | 130 ++++++++++
>>>>  hw/intc/xive.c                    | 379 ++++++++++++++++++++++++++++++
>>>>  hw/intc/Makefile.objs             |   1 +
>>>>  4 files changed, 511 insertions(+)
>>>>  create mode 100644 include/hw/ppc/xive.h
>>>>  create mode 100644 hw/intc/xive.c
>>>>
>>>> diff --git a/default-configs/ppc64-softmmu.mak 
>>>> b/default-configs/ppc64-softmmu.mak
>>>> index aec2855750d6..2d1e7c5c4668 100644
>>>> --- a/default-configs/ppc64-softmmu.mak
>>>> +++ b/default-configs/ppc64-softmmu.mak
>>>> @@ -16,6 +16,7 @@ CONFIG_VIRTIO_VGA=y
>>>>  CONFIG_XICS=$(CONFIG_PSERIES)
>>>>  CONFIG_XICS_SPAPR=$(CONFIG_PSERIES)
>>>>  CONFIG_XICS_KVM=$(call land,$(CONFIG_PSERIES),$(CONFIG_KVM))
>>>> +CONFIG_XIVE=$(CONFIG_PSERIES)
>>>>  CONFIG_MEM_DEVICE=y
>>>>  CONFIG_DIMM=y
>>>>  CONFIG_SPAPR_RNG=y
>>>> diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
>>>> new file mode 100644
>>>> index 000000000000..5fec4b08705d
>>>> --- /dev/null
>>>> +++ b/include/hw/ppc/xive.h
>>>> @@ -0,0 +1,130 @@
>>>> +/*
>>>> + * QEMU PowerPC XIVE interrupt controller model
>>>> + *
>>>> + * Copyright (c) 2017-2018, IBM Corporation.
>>>> + *
>>>> + * This code is licensed under the GPL version 2 or later. See the
>>>> + * COPYING file in the top-level directory.
>>>
>>> A cheat sheet in the top of this header with the old and new XIVE
>>> terms would quite nice to have.
>>
>> Yes. It's a good place. I will put the XIVE acronyms here :
>>      
>>      EA              Event Assignment
>>      EISN    Effective Interrupt Source Number
>>      END     Event Notification Descriptor
>>      ESB     Event State Buffer
>>      EQ              Event Queue
>>      LISN    Logical Interrupt Source Number
>>      NVT     Notification Virtual Target
>>      TIMA    Thread Interrupt Management Area
>>      ...
> 
> That sounds good, but what I'd also like is showing that NVT == VP and
> EAS == IVT and so forth.

sure. I will add that. 

skiboot and PowerNV Linux are using a mixed version and I wonder if I 
should not clarify that also, skiboot at least. 

>>>> + */
>>>> +
>>>> +#ifndef PPC_XIVE_H
>>>> +#define PPC_XIVE_H
>>>> +
>>>> +#include "hw/sysbus.h"
>>>
>>> So, I'm a bit dubious about making the XiveSource a SysBus device -
>>> I'm concerned it won't play well with tying it into the other devices
>>> like PHB that "own" it in real hardware.
>>
>> It does but I can take a look at changing it to a DeviceState. The 
>> reset handlers might be a concern.
> 
> As "non bus" device I think you'd need to register your own reset
> handler rather than just setting dc->reset.  Otherwise, I think that
> should work.

yes. I will give a look/try, it might not be such a problem. 

>>> I think we'd be better off making it a direct descendent of
>>> TYPE_DEVICE which constructs the MMIO region, but doesn't map it.
>>
>> At a moment, I started working on a XiveESB object doing what I think 
>> you are suggesting and I removed it. I am reluctant adding more 
>> complexity now, the patchset is just growing and growing ... 
>>
>> But I agree there are fundamentals to get right for KVM. Let's talk 
>> about it after you have looked at the overall patchset, at least up 
>> to KVM initial support.
> 
> Hm, ok.
> 
>>> Then we can havea SysBusDevice (and/or other) wrapper which
>>> instantiates the XiveSource core and maps it into somewhere
>>> accessible.
>>
>> The XIVE controller model does the mapping of the source currently.
> 
> I'm.. I'm not sure what you mean by that.   We have a
> sysbus_init_mmio() right here which effectively maps in the MMIO
> region AFAICT.

yes. what I meant is that the XIVE controller model does all the 
mapping, for the TIMA and for the ESB pages of the XiveSource. 

This is a 'critical' part of the XIVE model because the region have 
a different nature under KVM, which requires the KVM device to be 
created before the region are, and to be destroyed when the device
is. 

It took me a while to get all in place to support all aspects of 
the model: KVM and not KVM, switch of interrupt controller, machine 
reset, post_load, PowerNV devices, etc. So expect some resistant 
from me on that topic. 

Thanks,

C.

>> In the case of sPAPR, the controller model controls the TIMA and 
>> for PowerNV, there are quite few others MMIO regions to handle.
>>
>>>
>>>> +
>>>> +/*
>>>> + * XIVE Interrupt Source
>>>> + */
>>>> +
>>>> +#define TYPE_XIVE_SOURCE "xive-source"
>>>> +#define XIVE_SOURCE(obj) OBJECT_CHECK(XiveSource, (obj), TYPE_XIVE_SOURCE)
>>>> +
>>>> +/*
>>>> + * XIVE Interrupt Source characteristics, which define how the ESB are
>>>> + * controlled.
>>>> + */
>>>> +#define XIVE_SRC_H_INT_ESB     0x1 /* ESB managed with hcall H_INT_ESB */
>>>> +#define XIVE_SRC_STORE_EOI     0x2 /* Store EOI supported */
>>>> +
>>>> +typedef struct XiveSource {
>>>> +    SysBusDevice parent;
>>>> +
>>>> +    /* IRQs */
>>>> +    uint32_t        nr_irqs;
>>>> +    qemu_irq        *qirqs;
>>>> +
>>>> +    /* PQ bits */
>>>> +    uint8_t         *status;
>>>> +
>>>> +    /* ESB memory region */
>>>> +    uint64_t        esb_flags;
>>>> +    uint32_t        esb_shift;
>>>> +    MemoryRegion    esb_mmio;
>>>> +} XiveSource;
>>>> +
>>>> +/*
>>>> + * ESB MMIO setting. Can be one page, for both source triggering and
>>>> + * source management, or two different pages. See below for magic
>>>> + * values.
>>>> + */
>>>> +#define XIVE_ESB_4K          12 /* PSI HB only */
>>>> +#define XIVE_ESB_4K_2PAGE    13
>>>> +#define XIVE_ESB_64K         16
>>>> +#define XIVE_ESB_64K_2PAGE   17
>>>> +
>>>> +static inline bool xive_source_esb_has_2page(XiveSource *xsrc)
>>>> +{
>>>> +    return xsrc->esb_shift == XIVE_ESB_64K_2PAGE ||
>>>> +        xsrc->esb_shift == XIVE_ESB_4K_2PAGE;
>>>> +}
>>>> +
>>>> +/* The trigger page is always the first/even page */
>>>> +static inline hwaddr xive_source_esb_page(XiveSource *xsrc, uint32_t 
>>>> srcno)
>>>
>>> This function doesn't appear to be used anywhere except..
>>
>> It's used in patch 16 adding the hcalls also.
>>
>>>> +{
>>>> +    assert(srcno < xsrc->nr_irqs);
>>>> +    return (1ull << xsrc->esb_shift) * srcno;
>>>> +}
>>>> +
>>>> +/* In a two pages ESB MMIO setting, the odd page is for management */
>>>> +static inline hwaddr xive_source_esb_mgmt(XiveSource *xsrc, int srcno)
>>>
>>>
>>> ..here, and this function doesn't appear to be used anywhere.
>>
>> It's used in patch 16 adding the hcalls and patch 23 for KVM.
>>
>> This is basic ESB support which I thought belong to the patch on sources.
>>  
>>>
>>>> +{
>>>> +    hwaddr addr = xive_source_esb_page(xsrc, srcno);
>>>> +
>>>> +    if (xive_source_esb_has_2page(xsrc)) {
>>>> +        addr += (1 << (xsrc->esb_shift - 1));
>>>> +    }
>>>> +
>>>> +    return addr;
>>>> +}
>>>> +
>>>> +/*
>>>> + * Each interrupt source has a 2-bit state machine which can be
>>>> + * controlled by MMIO. P indicates that an interrupt is pending (has
>>>> + * been sent to a queue and is waiting for an EOI). Q indicates that
>>>> + * the interrupt has been triggered while pending.
>>>> + *
>>>> + * This acts as a coalescing mechanism in order to guarantee that a
>>>> + * given interrupt only occurs at most once in a queue.
>>>> + *
>>>> + * When doing an EOI, the Q bit will indicate if the interrupt
>>>> + * needs to be re-triggered.
>>>> + */
>>>> +#define XIVE_ESB_VAL_P        0x2
>>>> +#define XIVE_ESB_VAL_Q        0x1
>>>> +
>>>> +#define XIVE_ESB_RESET        0x0
>>>> +#define XIVE_ESB_PENDING      XIVE_ESB_VAL_P
>>>> +#define XIVE_ESB_QUEUED       (XIVE_ESB_VAL_P | XIVE_ESB_VAL_Q)
>>>> +#define XIVE_ESB_OFF          XIVE_ESB_VAL_Q
>>>> +
>>>> +/*
>>>> + * "magic" Event State Buffer (ESB) MMIO offsets.
>>>> + *
>>>> + * The following offsets into the ESB MMIO allow to read or manipulate
>>>> + * the PQ bits. They must be used with an 8-byte load instruction.
>>>> + * They all return the previous state of the interrupt (atomically).
>>>> + *
>>>> + * Additionally, some ESB pages support doing an EOI via a store and
>>>> + * some ESBs support doing a trigger via a separate trigger page.
>>>> + */
>>>> +#define XIVE_ESB_STORE_EOI      0x400 /* Store */
>>>> +#define XIVE_ESB_LOAD_EOI       0x000 /* Load */
>>>> +#define XIVE_ESB_GET            0x800 /* Load */
>>>> +#define XIVE_ESB_SET_PQ_00      0xc00 /* Load */
>>>> +#define XIVE_ESB_SET_PQ_01      0xd00 /* Load */
>>>> +#define XIVE_ESB_SET_PQ_10      0xe00 /* Load */
>>>> +#define XIVE_ESB_SET_PQ_11      0xf00 /* Load */
>>>> +
>>>> +uint8_t xive_source_esb_get(XiveSource *xsrc, uint32_t srcno);
>>>> +uint8_t xive_source_esb_set(XiveSource *xsrc, uint32_t srcno, uint8_t pq);
>>>> +
>>>> +void xive_source_pic_print_info(XiveSource *xsrc, uint32_t offset,
>>>> +                                Monitor *mon);
>>>> +
>>>> +static inline qemu_irq xive_source_qirq(XiveSource *xsrc, uint32_t srcno)
>>>> +{
>>>> +    assert(srcno < xsrc->nr_irqs);
>>>> +    return xsrc->qirqs[srcno];
>>>> +}
>>>> +
>>>> +#endif /* PPC_XIVE_H */
>>>> diff --git a/hw/intc/xive.c b/hw/intc/xive.c
>>>> new file mode 100644
>>>> index 000000000000..f7621f84828c
>>>> --- /dev/null
>>>> +++ b/hw/intc/xive.c
>>>> @@ -0,0 +1,379 @@
>>>> +/*
>>>> + * QEMU PowerPC XIVE interrupt controller model
>>>> + *
>>>> + * Copyright (c) 2017-2018, IBM Corporation.
>>>> + *
>>>> + * This code is licensed under the GPL version 2 or later. See the
>>>> + * COPYING file in the top-level directory.
>>>> + */
>>>> +
>>>> +#include "qemu/osdep.h"
>>>> +#include "qemu/log.h"
>>>> +#include "qapi/error.h"
>>>> +#include "target/ppc/cpu.h"
>>>> +#include "sysemu/cpus.h"
>>>> +#include "sysemu/dma.h"
>>>> +#include "monitor/monitor.h"
>>>> +#include "hw/ppc/xive.h"
>>>> +
>>>> +/*
>>>> + * XIVE ESB helpers
>>>> + */
>>>> +
>>>> +static uint8_t xive_esb_set(uint8_t *pq, uint8_t value)
>>>> +{
>>>> +    uint8_t old_pq = *pq & 0x3;
>>>> +
>>>> +    *pq &= ~0x3;
>>>> +    *pq |= value & 0x3;
>>>> +
>>>> +    return old_pq;
>>>> +}
>>>> +
>>>> +static bool xive_esb_trigger(uint8_t *pq)
>>>> +{
>>>> +    uint8_t old_pq = *pq & 0x3;
>>>> +
>>>> +    switch (old_pq) {
>>>> +    case XIVE_ESB_RESET:
>>>> +        xive_esb_set(pq, XIVE_ESB_PENDING);
>>>> +        return true;
>>>> +    case XIVE_ESB_PENDING:
>>>> +    case XIVE_ESB_QUEUED:
>>>> +        xive_esb_set(pq, XIVE_ESB_QUEUED);
>>>> +        return false;
>>>> +    case XIVE_ESB_OFF:
>>>> +        xive_esb_set(pq, XIVE_ESB_OFF);
>>>> +        return false;
>>>> +    default:
>>>> +         g_assert_not_reached();
>>>> +    }
>>>> +}
>>>> +
>>>> +static bool xive_esb_eoi(uint8_t *pq)
>>>> +{
>>>> +    uint8_t old_pq = *pq & 0x3;
>>>> +
>>>> +    switch (old_pq) {
>>>> +    case XIVE_ESB_RESET:
>>>> +    case XIVE_ESB_PENDING:
>>>> +        xive_esb_set(pq, XIVE_ESB_RESET);
>>>> +        return false;
>>>> +    case XIVE_ESB_QUEUED:
>>>> +        xive_esb_set(pq, XIVE_ESB_PENDING);
>>>> +        return true;
>>>> +    case XIVE_ESB_OFF:
>>>> +        xive_esb_set(pq, XIVE_ESB_OFF);
>>>> +        return false;
>>>> +    default:
>>>> +         g_assert_not_reached();
>>>> +    }
>>>> +}
>>>> +
>>>> +/*
>>>> + * XIVE Interrupt Source (or IVSE)
>>>> + */
>>>> +
>>>> +uint8_t xive_source_esb_get(XiveSource *xsrc, uint32_t srcno)
>>>> +{
>>>> +    assert(srcno < xsrc->nr_irqs);
>>>> +
>>>> +    return xsrc->status[srcno] & 0x3;
>>>> +}
>>>> +
>>>> +uint8_t xive_source_esb_set(XiveSource *xsrc, uint32_t srcno, uint8_t pq)
>>>> +{
>>>> +    assert(srcno < xsrc->nr_irqs);
>>>> +
>>>> +    return xive_esb_set(&xsrc->status[srcno], pq);
>>>> +}
>>>> +
>>>> +/*
>>>> + * Returns whether the event notification should be forwarded.
>>>> + */
>>>> +static bool xive_source_esb_trigger(XiveSource *xsrc, uint32_t srcno)
>>>> +{
>>>> +    assert(srcno < xsrc->nr_irqs);
>>>> +
>>>> +    return xive_esb_trigger(&xsrc->status[srcno]);
>>>> +}
>>>> +
>>>> +/*
>>>> + * Returns whether the event notification should be forwarded.
>>>> + */
>>>> +static bool xive_source_esb_eoi(XiveSource *xsrc, uint32_t srcno)
>>>> +{
>>>> +    assert(srcno < xsrc->nr_irqs);
>>>> +
>>>> +    return xive_esb_eoi(&xsrc->status[srcno]);
>>>> +}
>>>> +
>>>> +/*
>>>> + * Forward the source event notification to the Router
>>>> + */
>>>> +static void xive_source_notify(XiveSource *xsrc, int srcno)
>>>> +{
>>>> +
>>>> +}
>>>> +
>>>> +/*
>>>> + * In a two pages ESB MMIO setting, even page is the trigger page, odd
>>>> + * page is for management
>>>> + */
>>>> +static inline bool addr_is_even(hwaddr addr, uint32_t shift)
>>>> +{
>>>> +    return !((addr >> shift) & 1);
>>>> +}
>>>> +
>>>> +static inline bool xive_source_is_trigger_page(XiveSource *xsrc, hwaddr 
>>>> addr)
>>>> +{
>>>> +    return xive_source_esb_has_2page(xsrc) &&
>>>> +        addr_is_even(addr, xsrc->esb_shift - 1);
>>>> +}
>>>> +
>>>> +/*
>>>> + * ESB MMIO loads
>>>> + *                      Trigger page    Management/EOI page
>>>> + * 2 pages setting      even            odd
>>>> + *
>>>> + * 0x000 .. 0x3FF       -1              EOI and return 0|1
>>>> + * 0x400 .. 0x7FF       -1              EOI and return 0|1
>>>> + * 0x800 .. 0xBFF       -1              return PQ
>>>> + * 0xC00 .. 0xCFF       -1              return PQ and atomically PQ=0
>>>> + * 0xD00 .. 0xDFF       -1              return PQ and atomically PQ=0
>>>> + * 0xE00 .. 0xDFF       -1              return PQ and atomically PQ=1
>>>> + * 0xF00 .. 0xDFF       -1              return PQ and atomically PQ=1
>>>> + */
>>>
>>> I can't quite make sense of this table.  What do the -1s represent,
>>
>> the value returned by the load.
>>
>>> and how does it relate to the non-2page case?
>>
>> one page ESB support trigger and management on the same page. So for loads,
>> the odd page behavior applies.  
>>
>>>> +static uint64_t xive_source_esb_read(void *opaque, hwaddr addr, unsigned 
>>>> size)
>>>> +{
>>>> +    XiveSource *xsrc = XIVE_SOURCE(opaque);
>>>> +    uint32_t offset = addr & 0xFFF;
>>>> +    uint32_t srcno = addr >> xsrc->esb_shift;
>>>> +    uint64_t ret = -1;
>>>> +
>>>> +    /* In a two pages ESB MMIO setting, trigger page should not be read */
>>>> +    if (xive_source_is_trigger_page(xsrc, addr)) {
>>>> +        qemu_log_mask(LOG_GUEST_ERROR,
>>>> +                      "XIVE: invalid load on IRQ %d trigger page at "
>>>> +                      "0x%"HWADDR_PRIx"\n", srcno, addr);
>>>> +        return -1;
>>>> +    }
>>>> +
>>>> +    switch (offset) {
>>>> +    case XIVE_ESB_LOAD_EOI ... XIVE_ESB_LOAD_EOI + 0x7FF:
>>>> +        ret = xive_source_esb_eoi(xsrc, srcno);
>>>> +
>>>> +        /* Forward the source event notification for routing */
>>>> +        if (ret) {
>>>> +            xive_source_notify(xsrc, srcno);
>>>> +        }
>>>> +        break;
>>>> +
>>>> +    case XIVE_ESB_GET ... XIVE_ESB_GET + 0x3FF:
>>>> +        ret = xive_source_esb_get(xsrc, srcno);
>>>> +        break;
>>>> +
>>>> +    case XIVE_ESB_SET_PQ_00 ... XIVE_ESB_SET_PQ_00 + 0x0FF:
>>>> +    case XIVE_ESB_SET_PQ_01 ... XIVE_ESB_SET_PQ_01 + 0x0FF:
>>>> +    case XIVE_ESB_SET_PQ_10 ... XIVE_ESB_SET_PQ_10 + 0x0FF:
>>>> +    case XIVE_ESB_SET_PQ_11 ... XIVE_ESB_SET_PQ_11 + 0x0FF:
>>>> +        ret = xive_source_esb_set(xsrc, srcno, (offset >> 8) & 0x3);
>>>> +        break;
>>>> +    default:
>>>> +        qemu_log_mask(LOG_GUEST_ERROR, "XIVE: invalid ESB load addr %x\n",
>>>> +                      offset);
>>>> +    }
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>> +/*
>>>> + * ESB MMIO stores
>>>> + *                      Trigger page    Management/EOI page
>>>> + * 2 pages setting      even            odd
>>>
>>> As with the previous table, I don't quite understand what the headings
>>> above mean.
>>
>> one page ESB support trigger and management on the same page. So for stores,
>> the odd page behavior applies.
>>
>> The headings can be improved. I will think of something.
>>
>>>> + * 0x000 .. 0x3FF       Trigger         Trigger
>>>> + * 0x400 .. 0x7FF       Trigger         EOI
>>>> + * 0x800 .. 0xBFF       Trigger         undefined
>>>> + * 0xC00 .. 0xCFF       Trigger         PQ=00
>>>> + * 0xD00 .. 0xDFF       Trigger         PQ=01
>>>> + * 0xE00 .. 0xDFF       Trigger         PQ=10
>>>> + * 0xF00 .. 0xDFF       Trigger         PQ=11
>>>> + */
>>>> +static void xive_source_esb_write(void *opaque, hwaddr addr,
>>>> +                                  uint64_t value, unsigned size)
>>>> +{
>>>> +    XiveSource *xsrc = XIVE_SOURCE(opaque);
>>>> +    uint32_t offset = addr & 0xFFF;
>>>> +    uint32_t srcno = addr >> xsrc->esb_shift;
>>>> +    bool notify = false;
>>>> +
>>>> +    /* In a two pages ESB MMIO setting, trigger page only triggers */
>>>> +    if (xive_source_is_trigger_page(xsrc, addr)) {
>>>> +        notify = xive_source_esb_trigger(xsrc, srcno);
>>>> +        goto out;
>>>> +    }
>>>> +
>>>> +    switch (offset) {
>>>> +    case 0 ... 0x3FF:
>>>> +        notify = xive_source_esb_trigger(xsrc, srcno);
>>>> +        break;
>>>> +
>>>> +    case XIVE_ESB_STORE_EOI ... XIVE_ESB_STORE_EOI + 0x3FF:
>>>> +        if (!(xsrc->esb_flags & XIVE_SRC_STORE_EOI)) {
>>>> +            qemu_log_mask(LOG_GUEST_ERROR,
>>>> +                          "XIVE: invalid Store EOI for IRQ %d\n", srcno);
>>>> +            return;
>>>> +        }
>>>> +
>>>> +        notify = xive_source_esb_eoi(xsrc, srcno);
>>>> +        break;
>>>> +
>>>> +    case XIVE_ESB_SET_PQ_00 ... XIVE_ESB_SET_PQ_00 + 0x0FF:
>>>> +    case XIVE_ESB_SET_PQ_01 ... XIVE_ESB_SET_PQ_01 + 0x0FF:
>>>> +    case XIVE_ESB_SET_PQ_10 ... XIVE_ESB_SET_PQ_10 + 0x0FF:
>>>> +    case XIVE_ESB_SET_PQ_11 ... XIVE_ESB_SET_PQ_11 + 0x0FF:
>>>> +        xive_source_esb_set(xsrc, srcno, (offset >> 8) & 0x3);
>>>> +        break;
>>>> +
>>>> +    default:
>>>> +        qemu_log_mask(LOG_GUEST_ERROR, "XIVE: invalid ESB write addr 
>>>> %x\n",
>>>> +                      offset);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +out:
>>>> +    /* Forward the source event notification for routing */
>>>> +    if (notify) {
>>>> +        xive_source_notify(xsrc, srcno);
>>>> +    }
>>>> +}
>>>> +
>>>> +static const MemoryRegionOps xive_source_esb_ops = {
>>>> +    .read = xive_source_esb_read,
>>>> +    .write = xive_source_esb_write,
>>>> +    .endianness = DEVICE_BIG_ENDIAN,
>>>> +    .valid = {
>>>> +        .min_access_size = 8,
>>>> +        .max_access_size = 8,
>>>> +    },
>>>> +    .impl = {
>>>> +        .min_access_size = 8,
>>>> +        .max_access_size = 8,
>>>> +    },
>>>> +};
>>>> +
>>>> +static void xive_source_set_irq(void *opaque, int srcno, int val)
>>>> +{
>>>> +    XiveSource *xsrc = XIVE_SOURCE(opaque);
>>>> +    bool notify = false;
>>>> +
>>>> +    if (val) {
>>>> +        notify = xive_source_esb_trigger(xsrc, srcno);
>>>> +    }
>>>> +
>>>> +    /* Forward the source event notification for routing */
>>>> +    if (notify) {
>>>> +        xive_source_notify(xsrc, srcno);
>>>> +    }
>>>> +}
>>>> +
>>>> +void xive_source_pic_print_info(XiveSource *xsrc, uint32_t offset, 
>>>> Monitor *mon)
>>>> +{
>>>> +    int i;
>>>> +
>>>> +    for (i = 0; i < xsrc->nr_irqs; i++) {
>>>> +        uint8_t pq = xive_source_esb_get(xsrc, i);
>>>> +
>>>> +        if (pq == XIVE_ESB_OFF) {
>>>> +            continue;
>>>> +        }
>>>> +
>>>> +        monitor_printf(mon, "  %08x %c%c\n", i + offset,
>>>> +                       pq & XIVE_ESB_VAL_P ? 'P' : '-',
>>>> +                       pq & XIVE_ESB_VAL_Q ? 'Q' : '-');
>>>> +    }
>>>> +}
>>>> +
>>>> +static void xive_source_reset(DeviceState *dev)
>>>> +{
>>>> +    XiveSource *xsrc = XIVE_SOURCE(dev);
>>>> +
>>>> +    /* PQs are initialized to 0b01 which corresponds to "ints off" */
>>>> +    memset(xsrc->status, 0x1, xsrc->nr_irqs);
>>>
>>> You've already got XIVE_ESB_OFF defined to make this a little clearer.
>>
>> Sure.
>>
>> Thanks,
>>
>> C. 
>>
>>
>>>
>>>> +}
>>>> +
>>>> +static void xive_source_realize(DeviceState *dev, Error **errp)
>>>> +{
>>>> +    XiveSource *xsrc = XIVE_SOURCE(dev);
>>>> +
>>>> +    if (!xsrc->nr_irqs) {
>>>> +        error_setg(errp, "Number of interrupt needs to be greater than 
>>>> 0");
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    if (xsrc->esb_shift != XIVE_ESB_4K &&
>>>> +        xsrc->esb_shift != XIVE_ESB_4K_2PAGE &&
>>>> +        xsrc->esb_shift != XIVE_ESB_64K &&
>>>> +        xsrc->esb_shift != XIVE_ESB_64K_2PAGE) {
>>>> +        error_setg(errp, "Invalid ESB shift setting");
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    xsrc->qirqs = qemu_allocate_irqs(xive_source_set_irq, xsrc,
>>>> +                                     xsrc->nr_irqs);
>>>> +
>>>> +    xsrc->status = g_malloc0(xsrc->nr_irqs);
>>>> +
>>>> +    memory_region_init_io(&xsrc->esb_mmio, OBJECT(xsrc),
>>>> +                          &xive_source_esb_ops, xsrc, "xive.esb",
>>>> +                          (1ull << xsrc->esb_shift) * xsrc->nr_irqs);
>>>> +    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &xsrc->esb_mmio);
>>>> +}
>>>> +
>>>> +static const VMStateDescription vmstate_xive_source = {
>>>> +    .name = TYPE_XIVE_SOURCE,
>>>> +    .version_id = 1,
>>>> +    .minimum_version_id = 1,
>>>> +    .fields = (VMStateField[]) {
>>>> +        VMSTATE_UINT32_EQUAL(nr_irqs, XiveSource, NULL),
>>>> +        VMSTATE_VBUFFER_UINT32(status, XiveSource, 1, NULL, nr_irqs),
>>>> +        VMSTATE_END_OF_LIST()
>>>> +    },
>>>> +};
>>>> +
>>>> +/*
>>>> + * The default XIVE interrupt source setting for the ESB MMIOs is two
>>>> + * 64k pages without Store EOI, to be in sync with KVM.
>>>> + */
>>>> +static Property xive_source_properties[] = {
>>>> +    DEFINE_PROP_UINT64("flags", XiveSource, esb_flags, 0),
>>>> +    DEFINE_PROP_UINT32("nr-irqs", XiveSource, nr_irqs, 0),
>>>> +    DEFINE_PROP_UINT32("shift", XiveSource, esb_shift, 
>>>> XIVE_ESB_64K_2PAGE),
>>>> +    DEFINE_PROP_END_OF_LIST(),
>>>> +};
>>>> +
>>>> +static void xive_source_class_init(ObjectClass *klass, void *data)
>>>> +{
>>>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>>>> +
>>>> +    dc->desc    = "XIVE Interrupt Source";
>>>> +    dc->props   = xive_source_properties;
>>>> +    dc->realize = xive_source_realize;
>>>> +    dc->reset   = xive_source_reset;
>>>> +    dc->vmsd    = &vmstate_xive_source;
>>>> +}
>>>> +
>>>> +static const TypeInfo xive_source_info = {
>>>> +    .name          = TYPE_XIVE_SOURCE,
>>>> +    .parent        = TYPE_SYS_BUS_DEVICE,
>>>> +    .instance_size = sizeof(XiveSource),
>>>> +    .class_init    = xive_source_class_init,
>>>> +};
>>>> +
>>>> +static void xive_register_types(void)
>>>> +{
>>>> +    type_register_static(&xive_source_info);
>>>> +}
>>>> +
>>>> +type_init(xive_register_types)
>>>> diff --git a/hw/intc/Makefile.objs b/hw/intc/Makefile.objs
>>>> index 0e9963f5eecc..72a46ed91c31 100644
>>>> --- a/hw/intc/Makefile.objs
>>>> +++ b/hw/intc/Makefile.objs
>>>> @@ -37,6 +37,7 @@ obj-$(CONFIG_SH4) += sh_intc.o
>>>>  obj-$(CONFIG_XICS) += xics.o
>>>>  obj-$(CONFIG_XICS_SPAPR) += xics_spapr.o
>>>>  obj-$(CONFIG_XICS_KVM) += xics_kvm.o
>>>> +obj-$(CONFIG_XIVE) += xive.o
>>>>  obj-$(CONFIG_POWERNV) += xics_pnv.o
>>>>  obj-$(CONFIG_ALLWINNER_A10_PIC) += allwinner-a10-pic.o
>>>>  obj-$(CONFIG_S390_FLIC) += s390_flic.o
>>>
>>
>