Re: [Qemu-devel] [PATCH 8/8] xics: enable interrupt configuration reset on migration

[Alexander Graf <agraf@suse.de>]

On 14.03.14 05:18, Alexey Kardashevskiy wrote:
> Interrupt numbers migrate along with other properties so
> the initial QEMU setup will be reset by migration. Since
> XICS migrates as well and this includes IRQ map with all
> the flags saying which ones are already used, all we need
> is just to reset the XICS IRQ array on the destination.
>
> This resets XICS IRQ usage map.
>
> This enables devices to migrate IRQ number instead of
> checking that the number has not changed since
> the initialization.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

I'm not sure this is how it's supposed to work. Juan, what's the usual 
way to ensure that interrupt allocation stays identical between source 
and destination on migration?


Alex

> ---
>   hw/intc/xics.c        | 19 +++++++++++++++++++
>   hw/ppc/spapr_pci.c    |  2 +-
>   hw/ppc/spapr_vio.c    |  2 +-
>   include/hw/ppc/xics.h |  1 +
>   trace-events          |  1 +
>   5 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/hw/intc/xics.c b/hw/intc/xics.c
> index 8d101a3..0809a52 100644
> --- a/hw/intc/xics.c
> +++ b/hw/intc/xics.c
> @@ -33,6 +33,8 @@
>   #include "qemu/error-report.h"
>   #include "qapi/visitor.h"
>   
> +static void ics_free(ICSState *ics, int irq, int num);
> +
>   static int get_cpu_index_by_dt_id(int cpu_dt_id)
>   {
>       PowerPCCPU *cpu = ppc_get_vcpu_by_dt_id(cpu_dt_id);
> @@ -531,6 +533,12 @@ static void ics_reset(DeviceState *dev)
>       }
>   }
>   
> +static int ics_pre_load(ICSState *ics)
> +{
> +    ics_free(ics, ics->offset, ics->nr_irqs);
> +    return 0;
> +}
> +
>   static int ics_post_load(ICSState *ics, int version_id)
>   {
>       int i;
> @@ -635,6 +643,7 @@ static void ics_class_init(ObjectClass *klass, void *data)
>       dc->realize = ics_realize;
>       dc->vmsd = &vmstate_ics;
>       dc->reset = ics_reset;
> +    isc->pre_load = ics_pre_load;
>       isc->post_load = ics_post_load;
>   }
>   
> @@ -770,6 +779,16 @@ int xics_alloc_block(XICSState *icp, int server, int num, bool lsi, bool align)
>       return first;
>   }
>   
> +static void ics_free(ICSState *ics, int irq, int num)
> +{
> +    int i;
> +
> +    trace_xics_ics_free(ics - ics->icp->ics, irq, num);
> +    for (i = irq; i < irq + num; ++i) {
> +        memset(&ics->irqs[i], 0, sizeof(ICSIRQState));
> +    }
> +}
> +
>   /*
>    * Guest interfaces
>    */
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 4eaf364..aa12d1a 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -661,7 +661,7 @@ static const VMStateDescription vmstate_spapr_pci_lsi = {
>       .minimum_version_id = 1,
>       .minimum_version_id_old = 1,
>       .fields      = (VMStateField []) {
> -        VMSTATE_UINT32_EQUAL(irq, struct spapr_pci_lsi),
> +        VMSTATE_UINT32(irq, struct spapr_pci_lsi),
>   
>           VMSTATE_END_OF_LIST()
>       },
> diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c
> index 8aeb263..022c914 100644
> --- a/hw/ppc/spapr_vio.c
> +++ b/hw/ppc/spapr_vio.c
> @@ -548,7 +548,7 @@ const VMStateDescription vmstate_spapr_vio = {
>       .fields      = (VMStateField []) {
>           /* Sanity check */
>           VMSTATE_UINT32_EQUAL(reg, VIOsPAPRDevice),
> -        VMSTATE_UINT32_EQUAL(irq, VIOsPAPRDevice),
> +        VMSTATE_UINT32(irq, VIOsPAPRDevice),
>   
>           /* General VIO device state */
>           VMSTATE_UINTTL(signal_state, VIOsPAPRDevice),
> diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
> index 337398d..6ee6279 100644
> --- a/include/hw/ppc/xics.h
> +++ b/include/hw/ppc/xics.h
> @@ -159,6 +159,7 @@ qemu_irq xics_get_qirq(XICSState *icp, int irq);
>   void xics_set_irq_type(XICSState *icp, int irq, bool lsi);
>   int xics_alloc(XICSState *icp, int server, int irq, bool lsi);
>   int xics_alloc_block(XICSState *icp, int server, int num, bool lsi, bool align);
> +void xics_free(XICSState *icp, int server, int irq, int num);
>   
>   void xics_cpu_setup(XICSState *icp, PowerPCCPU *cpu);
>   
> diff --git a/trace-events b/trace-events
> index ad7400e..948ab93 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1146,6 +1146,7 @@ xics_ics_eoi(int nr) "ics_eoi: irq %#x"
>   xics_alloc(int server, int irq) "server#%d, irq %d"
>   xics_alloc_failed(int server, int irq) "server#%d, irq %d"
>   xics_alloc_block(int server, int first, int num, bool lsi, int align) "server#%d, first irq %d, %d irqs, lsi=%d, alignnum %d"
> +xics_ics_free(int server, int irq, int num) "server#%d, first irq %d, %d irqs"
>   
>   # hw/ppc/spapr_iommu.c
>   spapr_iommu_put(uint64_t liobn, uint64_t ioba, uint64_t tce, uint64_t ret) "liobn=%"PRIx64" ioba=0x%"PRIx64" tce=0x%"PRIx64" ret=%"PRId64