Re: [PATCH v2 15/30] KVM: s390: pci: do initial setup for AEN interpretation

[Matthew Rosato <mjrosato@linux.ibm.com>]

On 1/19/22 1:06 PM, Pierre Morel wrote:
> 
> 
> On 1/14/22 21:31, Matthew Rosato wrote:
>> Initial setup for Adapter Event Notification Interpretation for zPCI
>> passthrough devices.  Specifically, allocate a structure for 
>> forwarding of
>> adapter events and pass the address of this structure to firmware.
>>
>> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
>> ---
>>   arch/s390/include/asm/pci.h      |   4 +
>>   arch/s390/include/asm/pci_insn.h |  12 +++
>>   arch/s390/kvm/interrupt.c        |  14 +++
>>   arch/s390/kvm/kvm-s390.c         |   9 ++
>>   arch/s390/kvm/pci.c              | 144 +++++++++++++++++++++++++++++++
>>   arch/s390/kvm/pci.h              |  42 +++++++++
>>   arch/s390/pci/pci.c              |   6 ++
>>   7 files changed, 231 insertions(+)
>>   create mode 100644 arch/s390/kvm/pci.h
>>
>> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
>> index 9b6c657d8d31..9ff8dc19975e 100644
>> --- a/arch/s390/include/asm/pci.h
>> +++ b/arch/s390/include/asm/pci.h
>> @@ -9,6 +9,7 @@
>>   #include <asm-generic/pci.h>
>>   #include <asm/pci_clp.h>
>>   #include <asm/pci_debug.h>
>> +#include <asm/pci_insn.h>
>>   #include <asm/sclp.h>
>>   #define PCIBIOS_MIN_IO        0x1000
>> @@ -204,6 +205,9 @@ extern const struct attribute_group 
>> *zpci_attr_groups[];
>>   extern unsigned int s390_pci_force_floating __initdata;
>>   extern unsigned int s390_pci_no_rid;
>> +extern union zpci_sic_iib *zpci_aipb;
>> +extern struct airq_iv *zpci_aif_sbv;
>> +
>>   /* 
>> ----------------------------------------------------------------------------- 
>>
>>     Prototypes
>>   
>> ----------------------------------------------------------------------------- 
>> */
>> diff --git a/arch/s390/include/asm/pci_insn.h 
>> b/arch/s390/include/asm/pci_insn.h
>> index 32759c407b8f..ad9000295c82 100644
>> --- a/arch/s390/include/asm/pci_insn.h
>> +++ b/arch/s390/include/asm/pci_insn.h
>> @@ -101,6 +101,7 @@ struct zpci_fib {
>>   /* Set Interruption Controls Operation Controls  */
>>   #define    SIC_IRQ_MODE_ALL        0
>>   #define    SIC_IRQ_MODE_SINGLE        1
>> +#define    SIC_SET_AENI_CONTROLS        2
>>   #define    SIC_IRQ_MODE_DIRECT        4
>>   #define    SIC_IRQ_MODE_D_ALL        16
>>   #define    SIC_IRQ_MODE_D_SINGLE        17
>> @@ -127,9 +128,20 @@ struct zpci_cdiib {
>>       u64 : 64;
>>   } __packed __aligned(8);
>> +/* adapter interruption parameters block */
>> +struct zpci_aipb {
>> +    u64 faisb;
>> +    u64 gait;
>> +    u16 : 13;
>> +    u16 afi : 3;
>> +    u32 : 32;
>> +    u16 faal;
>> +} __packed __aligned(8);
>> +
>>   union zpci_sic_iib {
>>       struct zpci_diib diib;
>>       struct zpci_cdiib cdiib;
>> +    struct zpci_aipb aipb;
>>   };
>>   DECLARE_STATIC_KEY_FALSE(have_mio);
>> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
>> index f9b872e358c6..a591b8cd662f 100644
>> --- a/arch/s390/kvm/interrupt.c
>> +++ b/arch/s390/kvm/interrupt.c
>> @@ -32,6 +32,7 @@
>>   #include "kvm-s390.h"
>>   #include "gaccess.h"
>>   #include "trace-s390.h"
>> +#include "pci.h"
>>   #define PFAULT_INIT 0x0600
>>   #define PFAULT_DONE 0x0680
>> @@ -3278,6 +3279,11 @@ void kvm_s390_gib_destroy(void)
>>   {
>>       if (!gib)
>>           return;
>> +    if (IS_ENABLED(CONFIG_PCI) && sclp.has_aeni && aift) {
>> +        mutex_lock(&aift->lock);
>> +        kvm_s390_pci_aen_exit();
>> +        mutex_unlock(&aift->lock);
>> +    }
>>       chsc_sgib(0);
>>       unregister_adapter_interrupt(&gib_alert_irq);
>>       free_page((unsigned long)gib);
>> @@ -3315,6 +3321,14 @@ int kvm_s390_gib_init(u8 nisc)
>>           goto out_unreg_gal;
>>       }
>> +    if (IS_ENABLED(CONFIG_PCI) && sclp.has_aeni) {
>> +        if (kvm_s390_pci_aen_init(nisc)) {
>> +            pr_err("Initializing AEN for PCI failed\n");
>> +            rc = -EIO;
>> +            goto out_unreg_gal;
>> +        }
>> +    }
>> +
>>       KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
>>       goto out;
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index 14a18ba5ff2c..01dc3f6883d0 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -48,6 +48,7 @@
>>   #include <asm/fpu/api.h>
>>   #include "kvm-s390.h"
>>   #include "gaccess.h"
>> +#include "pci.h"
>>   #define CREATE_TRACE_POINTS
>>   #include "trace.h"
>> @@ -503,6 +504,14 @@ int kvm_arch_init(void *opaque)
>>           goto out;
>>       }
>> +    if (IS_ENABLED(CONFIG_PCI)) {
>> +        rc = kvm_s390_pci_init();
>> +        if (rc) {
>> +            pr_err("Unable to allocate AIFT for PCI\n");
>> +            goto out;
>> +        }
>> +    }
>> +
>>       rc = kvm_s390_gib_init(GAL_ISC);
>>       if (rc)
>>           goto out;
>> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
>> index 1c33bc7bf2bd..dae853da6df1 100644
>> --- a/arch/s390/kvm/pci.c
>> +++ b/arch/s390/kvm/pci.c
>> @@ -10,6 +10,138 @@
>>   #include <linux/kvm_host.h>
>>   #include <linux/pci.h>
>>   #include <asm/kvm_pci.h>
>> +#include <asm/pci.h>
>> +#include <asm/pci_insn.h>
>> +#include "pci.h"
>> +
>> +struct zpci_aift *aift;
>> +
>> +static inline int __set_irq_noiib(u16 ctl, u8 isc)
>> +{
>> +    union zpci_sic_iib iib = {{0}};
>> +
>> +    return zpci_set_irq_ctrl(ctl, isc, &iib);
>> +}
>> +
>> +/* Caller must hold the aift lock before calling this function */
>> +void kvm_s390_pci_aen_exit(void)
>> +{
>> +    unsigned long flags;
>> +    struct kvm_zdev **gait_kzdev;
>> +
>> +    /*
>> +     * Contents of the aipb remain registered for the life of the host
>> +     * kernel, the information preserved in zpci_aipb and zpci_aif_sbv
>> +     * in case we insert the KVM module again later.  Clear the AIFT
>> +     * information and free anything not registered with underlying
>> +     * firmware.
>> +     */
>> +    spin_lock_irqsave(&aift->gait_lock, flags);
>> +    gait_kzdev = aift->kzdev;
>> +    aift->gait = 0;
>> +    aift->sbv = 0;
>> +    aift->kzdev = 0;
>> +    spin_unlock_irqrestore(&aift->gait_lock, flags);
>> +
>> +    kfree(gait_kzdev);
>> +}
>> +
>> +int kvm_s390_pci_aen_init(u8 nisc)
>> +{
>> +    struct page *page;
>> +    int rc = 0, size;
>> +    bool first = false;
>> +
>> +    /* If already enabled for AEN, bail out now */
>> +    if (aift->gait || aift->sbv)
>> +        return -EPERM;
>> +
>> +    mutex_lock(&aift->lock);
>> +    aift->kzdev = kcalloc(ZPCI_NR_DEVICES, sizeof(struct kvm_zdev),
>> +                  GFP_KERNEL);
>> +    if (!aift->kzdev) {
>> +        rc = -ENOMEM;
>> +        goto unlock;
>> +    }
>> +
>> +    if (!zpci_aipb) {
> 
> I think you should externalize all this allocation and setup of aipb
> in a dedicated function zpci_setup_aipb()
> from here ----->
> 
>> +        zpci_aipb = kzalloc(sizeof(union zpci_sic_iib), GFP_KERNEL);
>> +        if (!zpci_aipb) {
>> +            rc = -ENOMEM;
>> +            goto free_zdev;
>> +        }
>> +        first = true;
>> +        aift->sbv = airq_iv_create(ZPCI_NR_DEVICES, AIRQ_IV_ALLOC, 0);
>> +        if (!aift->sbv) {
>> +            rc = -ENOMEM;
>> +            goto free_aipb;
>> +        }
>> +        zpci_aif_sbv = aift->sbv;
>> +        size = get_order(PAGE_ALIGN(ZPCI_NR_DEVICES *
>> +                        sizeof(struct zpci_gaite)));
>> +        page = alloc_pages(GFP_KERNEL | __GFP_ZERO, size);
>> +        if (!page) {
>> +            rc = -ENOMEM;
>> +            goto free_sbv;
>> +        }
>> +        aift->gait = (struct zpci_gaite *)page_to_phys(page);
>> +
>> +        zpci_aipb->aipb.faisb = virt_to_phys(aift->sbv->vector);
>> +        zpci_aipb->aipb.gait = virt_to_phys(aift->gait);
>> +        zpci_aipb->aipb.afi = nisc;
>> +        zpci_aipb->aipb.faal = ZPCI_NR_DEVICES;
>> +
>> +        /* Setup Adapter Event Notification Interpretation */
>> +        if (zpci_set_irq_ctrl(SIC_SET_AENI_CONTROLS, 0, zpci_aipb)) {
>> +            rc = -EIO;
>> +            goto free_gait;
> 
> to here---->
> 
>> +        }
>> +    } else {
>> +        /*
>> +         * AEN registration can only happen once per system boot.  If
>> +         * an aipb already exists then AEN was already registered and
>> +         * we can re-use the aipb contents.  This can only happen if
>> +         * the KVM module was removed and re-inserted.
>> +         */
>> +        if (zpci_aipb->aipb.afi != nisc ||
>> +            zpci_aipb->aipb.faal != ZPCI_NR_DEVICES) {
>> +            rc = -EINVAL;
>> +            goto free_zdev;
>> +        }
>> +        aift->sbv = zpci_aif_sbv;
>> +        aift->gait = (struct zpci_gaite *)zpci_aipb->aipb.gait;
>> +    }
>> +
>> +    /* Enable floating IRQs */
>> +    if (__set_irq_noiib(SIC_IRQ_MODE_SINGLE, nisc)) {
>> +        rc = -EIO;
>> +        kvm_s390_pci_aen_exit();
>> +    }
>> +
>> +    goto unlock;
> 
> and the according errors
> 
> here ---->
>> +
>> +free_gait:
>> +    size = get_order(PAGE_ALIGN(ZPCI_NR_DEVICES *
>> +                    sizeof(struct zpci_gaite)));
>> +    free_pages((unsigned long)aift->gait, size);
>> +free_sbv:
>> +    if (first) {
>> +        /* If AEN setup failed, only free a newly-allocated sbv */
>> +        airq_iv_release(aift->sbv);
>> +        zpci_aif_sbv = 0;
>> +    }
>> +free_aipb:
>> +    if (first) {
>> +        /* If AEN setup failed, only free a newly-allocated aipb */
>> +        kfree(zpci_aipb);
>> +        zpci_aipb = 0;
>> +    }
> 
> to here ---->
> 
> To simplify the understanding.
> 
>> +free_zdev:
>> +    kfree(aift->kzdev);
>> +unlock:
>> +    mutex_unlock(&aift->lock);
>> +    return rc;
>> +}
>>
> 
> ... snip...
> 
> The second part of the if(aipb) else
> could also be externalise in zpci_reset_aipb()
> 
> which leads to
> 
>     if(!aipb)
>      ret = zpci_setup_aipb()
>     else
>      ret = zpci_reset_aipb()
> 
>     if (ret)
>      goto cleanup;
> 
>      enable_irq()
>      goto unlock;
> 
> I think that if we can do that it would be much clearer.
> what do you think?
> 

Yup, that sounds good, I will re-organize with 2 new static functions 
zpci_setup_aipb() and zpci_reset_aipb()