From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Mueller Subject: Re: [PATCH v5 14/15] KVM: s390: add and wire function gib_alert_irq_handler() Date: Tue, 8 Jan 2019 11:06:04 +0100 Message-ID: References: <20181219191756.57973-1-mimu@linux.ibm.com> <20181219191756.57973-15-mimu@linux.ibm.com> <7dfe72db-97d2-9f33-68f7-acf8ec5ddc5e@linux.ibm.com> Reply-To: mimu@linux.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <7dfe72db-97d2-9f33-68f7-acf8ec5ddc5e@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: pmorel@linux.ibm.com, KVM Mailing List Cc: Linux-S390 Mailing List , linux-kernel@vger.kernel.org, Martin Schwidefsky , Heiko Carstens , Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , Halil Pasic List-ID: On 03.01.19 16:16, Pierre Morel wrote: > On 19/12/2018 20:17, Michael Mueller wrote: >> The patch implements a handler for GIB alert interruptions >> on the host. Its task is to alert guests that interrupts are >> pending for them. >> >> A GIB alert interrupt statistic counter is added as well: >> >> $ cat /proc/interrupts >>            CPU0       CPU1 >>    ... >>    GAL:      23         37   [I/O] GIB Alert >>    ... >> >> Signed-off-by: Michael Mueller >> --- >>   arch/s390/include/asm/irq.h |  1 + >>   arch/s390/include/asm/isc.h |  1 + >>   arch/s390/kernel/irq.c      |  1 + >>   arch/s390/kvm/interrupt.c   | 36 ++++++++++++++++++++++++++++++++++-- >>   4 files changed, 37 insertions(+), 2 deletions(-) >> >> diff --git a/arch/s390/include/asm/irq.h b/arch/s390/include/asm/irq.h >> index 2f7f27e5493f..afaf5e3c57fd 100644 >> --- a/arch/s390/include/asm/irq.h >> +++ b/arch/s390/include/asm/irq.h >> @@ -62,6 +62,7 @@ enum interruption_class { >>       IRQIO_MSI, >>       IRQIO_VIR, >>       IRQIO_VAI, >> +    IRQIO_GAL, >>       NMI_NMI, >>       CPU_RST, >>       NR_ARCH_IRQS >> diff --git a/arch/s390/include/asm/isc.h b/arch/s390/include/asm/isc.h >> index 6cb9e2ed05b6..b2cc1ec78d06 100644 >> --- a/arch/s390/include/asm/isc.h >> +++ b/arch/s390/include/asm/isc.h >> @@ -21,6 +21,7 @@ >>   /* Adapter interrupts. */ >>   #define QDIO_AIRQ_ISC IO_SCH_ISC    /* I/O subchannel in qdio mode */ >>   #define PCI_ISC 2            /* PCI I/O subchannels */ >> +#define GAL_ISC 5            /* GIB alert */ >>   #define AP_ISC 6            /* adjunct processor (crypto) devices */ >>   /* Functions for registration of I/O interruption subclasses */ >> diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c >> index 0e8d68bac82c..0cd5a5f96729 100644 >> --- a/arch/s390/kernel/irq.c >> +++ b/arch/s390/kernel/irq.c >> @@ -88,6 +88,7 @@ static const struct irq_class irqclass_sub_desc[] = { >>       {.irq = IRQIO_MSI,  .name = "MSI", .desc = "[I/O] MSI Interrupt" }, >>       {.irq = IRQIO_VIR,  .name = "VIR", .desc = "[I/O] Virtual I/O >> Devices"}, >>       {.irq = IRQIO_VAI,  .name = "VAI", .desc = "[I/O] Virtual I/O >> Devices AI"}, >> +    {.irq = IRQIO_GAL,  .name = "GAL", .desc = "[I/O] GIB Alert"}, >>       {.irq = NMI_NMI,    .name = "NMI", .desc = "[NMI] Machine Check"}, >>       {.irq = CPU_RST,    .name = "RST", .desc = "[CPU] CPU Restart"}, >>   }; >> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c >> index 03e7ba4f215a..79b9c262479b 100644 >> --- a/arch/s390/kvm/interrupt.c >> +++ b/arch/s390/kvm/interrupt.c >> @@ -26,6 +26,7 @@ >>   #include >>   #include >>   #include >> +#include >>   #include "kvm-s390.h" >>   #include "gaccess.h" >>   #include "trace-s390.h" >> @@ -3043,7 +3044,7 @@ static void __floating_airqs_kick(struct kvm *kvm) >>   #define NONE_GISA_ADDR 0x00000001UL >>   #define GISA_ADDR_MASK 0xfffff000UL >> -static void __maybe_unused process_gib_alert_list(void) >> +static void process_gib_alert_list(void) >>   { >>       u32 final, next_alert, origin = 0UL; >>       struct kvm_s390_gisa *gisa; >> @@ -3091,7 +3092,10 @@ void kvm_s390_gisa_clear(struct kvm *kvm) >>   { >>       if (!kvm->arch.gisa) >>           return; >> +    if (set_iam(kvm->arch.gisa, 0) == -EBUSY) >> +        process_gib_alert_list(); > > We call process_gib_alert_list() from different contexts shouldn't we > protect the calls? That should not be necessary as the xcgh() guarantees that both instances will work on gib alert lists with disjunctive gisas. > > >>       nullify_gisa(kvm->arch.gisa); >> +    set_iam(kvm->arch.gisa, kvm->arch.iam); >>       VM_EVENT(kvm, 3, "gisa 0x%pK cleared", kvm->arch.gisa); >>   } >> @@ -3111,6 +3115,8 @@ void kvm_s390_gisa_destroy(struct kvm *kvm) >>   { >>       if (!kvm->arch.gisa) >>           return; >> +    if (set_iam(kvm->arch.gisa, 0) == -EBUSY) >> +        process_gib_alert_list(); > > idem. > >>       kvm->arch.gisa = NULL; >>   } >> @@ -3159,11 +3165,23 @@ int kvm_s390_gisc_unregister(struct kvm *kvm, >> u32 gisc) >>   } >>   EXPORT_SYMBOL_GPL(kvm_s390_gisc_unregister); >> +static void gib_alert_irq_handler(struct airq_struct *airq) >> +{ >> +    inc_irq_stat(IRQIO_GAL); >> +    process_gib_alert_list(); > > idem. > >> +} >> + >> +static struct airq_struct gib_alert_irq = { >> +    .handler = gib_alert_irq_handler, >> +    .lsi_ptr = &gib_alert_irq.lsi_mask, >> +}; >> + >