Re: [PATCH v5 11/21] KVM: s390: pci: do initial setup for AEN interpretation

Pierre Morel
2022-04-19T08:15:32Z

On 4/4/22 19:43, 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 | 153 +++++++++++++++++++++++++++++++
> arch/s390/kvm/pci.h | 47 ++++++++++
> arch/s390/pci/pci.c | 6 ++
> 7 files changed, 245 insertions(+)
>
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index 9eb20cebaa18..557b0ffb32d2 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 5331082fa516..e5f57cfe1d45 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 250119a26c60..57a27dfc85ea 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
> @@ -3328,6 +3329,11 @@ void kvm_s390_gib_destroy(void)
> {
> if (!gib)
> return;
> + if (kvm_s390_pci_interp_allowed() && aift) {
> + mutex_lock(&aift->aift_lock);
> + kvm_s390_pci_aen_exit();
> + mutex_unlock(&aift->aift_lock);
> + }
> chsc_sgib(0);
> unregister_adapter_interrupt(&gib_alert_irq);
> free_page((unsigned long)gib);
> @@ -3365,6 +3371,14 @@ int kvm_s390_gib_init(u8 nisc)
> goto out_unreg_gal;
> }
>
> + if (kvm_s390_pci_interp_allowed()) {
> + 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 156d1c25a3c1..9db6f8080f71 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -47,6 +47,7 @@
> #include <asm/fpu/api.h>
> #include "kvm-s390.h"
> #include "gaccess.h"
> +#include "pci.h"
>
> #define CREATE_TRACE_POINTS
> #include "trace.h"
> @@ -502,6 +503,14 @@ int kvm_arch_init(void *opaque)
> goto out;
> }
>
> + if (kvm_s390_pci_interp_allowed()) {
> + 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 213be236c05a..01bd8a2f503b 100644
> --- a/arch/s390/kvm/pci.c
> +++ b/arch/s390/kvm/pci.c
> @@ -9,8 +9,149 @@
>
> #include <linux/kvm_host.h>
> #include <linux/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);
> +}
> +
> +static int zpci_setup_aipb(u8 nisc)
> +{
> + struct page *page;
> + int size, rc;
> +
> + zpci_aipb = kzalloc(sizeof(union zpci_sic_iib), GFP_KERNEL);
> + if (!zpci_aipb)
> + return -ENOMEM;
> +
> + 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;
> + }
> +
> + return 0;
> +
> +free_gait:
> + size = get_order(PAGE_ALIGN(ZPCI_NR_DEVICES *
> + sizeof(struct zpci_gaite)));
> + free_pages((unsigned long)aift->gait, size);
> +free_sbv:
> + airq_iv_release(aift->sbv);
> + zpci_aif_sbv = 0;
> +free_aipb:
> + kfree(zpci_aipb);
> + zpci_aipb = 0;
> +
> + return rc;
> +}
> +
> +static int zpci_reset_aipb(u8 nisc)
> +{
> + /*
> + * 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.faal != ZPCI_NR_DEVICES ||
> + zpci_aipb->aipb.afi != nisc) {
> + return -EINVAL;
> + }

I do not understand how faal cound be different of ZPCI_NR_DEVICES if
aipb has been already initialised.
Same for afi.
Can you please explain?

> + aift->sbv = zpci_aif_sbv;
> + aift->gait = (struct zpci_gaite *)zpci_aipb->aipb.gait;
> +
> + return 0;
> +}
> +
> +int kvm_s390_pci_aen_init(u8 nisc)
> +{
> + int rc = 0;
> +
> + /* If already enabled for AEN, bail out now */
> + if (aift->gait || aift->sbv)
> + return -EPERM;
> +
> + mutex_lock(&aift->aift_lock);
> + aift->kzdev = kcalloc(ZPCI_NR_DEVICES, sizeof(struct kvm_zdev),
> + GFP_KERNEL);
> + if (!aift->kzdev) {
> + rc = -ENOMEM;
> + goto unlock;
> + }
> +
> + if (!zpci_aipb)
> + rc = zpci_setup_aipb(nisc);
> + else
> + rc = zpci_reset_aipb(nisc);
> + if (rc)
> + goto free_zdev;
> +
> + /* Enable floating IRQs */
> + if (__set_irq_noiib(SIC_IRQ_MODE_SINGLE, nisc)) {
> + rc = -EIO;
> + kvm_s390_pci_aen_exit();
> + }
> +
> + goto unlock;
> +
> +free_zdev:
> + kfree(aift->kzdev);
> +unlock:
> + mutex_unlock(&aift->aift_lock);
> + return rc;
> +}
> +
> int kvm_s390_pci_dev_open(struct zpci_dev *zdev)
> {
> struct kvm_zdev *kzdev;
> @@ -36,3 +177,15 @@ void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
> kfree(kzdev);
> }
> EXPORT_SYMBOL_GPL(kvm_s390_pci_dev_release);
> +
> +int kvm_s390_pci_init(void)
> +{
> + aift = kzalloc(sizeof(struct zpci_aift), GFP_KERNEL);
> + if (!aift)
> + return -ENOMEM;
> +
> + spin_lock_init(&aift->gait_lock);
> + mutex_init(&aift->aift_lock);
> +
> + return 0;
> +}
> diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
> index ce93978e8913..a6a62db792b6 100644
> --- a/arch/s390/kvm/pci.h
> +++ b/arch/s390/kvm/pci.h
> @@ -12,10 +12,57 @@
>
> #include <linux/kvm_host.h>
> #include <linux/pci.h>
> +#include <linux/mutex.h>
> +#include <asm/airq.h>
> +#include <asm/cpu.h>
>
> struct kvm_zdev {
> struct zpci_dev *zdev;
> struct kvm *kvm;
> };
>
> +struct zpci_gaite {
> + u32 gisa;
> + u8 gisc;
> + u8 count;
> + u8 reserved;
> + u8 aisbo;
> + u64 aisb;
> +};
> +
> +struct zpci_aift {
> + struct zpci_gaite *gait;
> + struct airq_iv *sbv;
> + struct kvm_zdev **kzdev;
> + spinlock_t gait_lock; /* Protects the gait, used during AEN forward */
> + struct mutex aift_lock; /* Protects the other structures in aift */
> +};
> +
> +extern struct zpci_aift *aift;
> +
> +int kvm_s390_pci_aen_init(u8 nisc);
> +void kvm_s390_pci_aen_exit(void);
> +
> +int kvm_s390_pci_init(void);
> +
> +static inline bool kvm_s390_pci_interp_allowed(void)
> +{
> + struct cpuid cpu_id;
> +
> + get_cpu_id(&cpu_id);
> + switch (cpu_id.machine) {
> + case 0x2817:
> + case 0x2818:
> + case 0x2827:
> + case 0x2828:
> + case 0x2964:
> + case 0x2965:
> + /* No SHM on certain machines */
> + return false;
> + default:
> + return (IS_ENABLED(CONFIG_VFIO_PCI) && sclp.has_zpci_lsi &&
> + sclp.has_aeni && sclp.has_aisi && sclp.has_aisii);
> + }
> +}
> +
> #endif /* __KVM_S390_PCI_H */
> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
> index a86cd1cbb80e..f0a439c43395 100644
> --- a/arch/s390/pci/pci.c
> +++ b/arch/s390/pci/pci.c
> @@ -61,6 +61,12 @@ DEFINE_STATIC_KEY_FALSE(have_mio);
>
> static struct kmem_cache *zdev_fmb_cache;
>
> +/* AEN structures that must be preserved over KVM module re-insertion */
> +union zpci_sic_iib *zpci_aipb;
> +EXPORT_SYMBOL_GPL(zpci_aipb);
> +struct airq_iv *zpci_aif_sbv;
> +EXPORT_SYMBOL_GPL(zpci_aif_sbv);
> +
> struct zpci_dev *get_zdev_by_fid(u32 fid)
> {
> struct zpci_dev *tmp, *zdev = NULL;
>

--
Pierre Morel
IBM Lab Boeblingen