Re: [PATCH 14/32] KVM: s390: pci: do initial setup for AEN interpretation

[Pierre Morel <pmorel@linux.ibm.com>]

On 12/7/21 21:57, 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_insn.h |  12 ++++
>   arch/s390/kvm/interrupt.c        |  17 +++++
>   arch/s390/kvm/kvm-s390.c         |   3 +
>   arch/s390/kvm/pci.c              | 113 +++++++++++++++++++++++++++++++
>   arch/s390/kvm/pci.h              |  42 ++++++++++++
>   5 files changed, 187 insertions(+)
>   create mode 100644 arch/s390/kvm/pci.h
> 
> 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 f9b872e358c6..4efe0e95a40f 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
> @@ -3276,8 +3277,16 @@ static struct airq_struct gib_alert_irq = {
>   
>   void kvm_s390_gib_destroy(void)
>   {
> +	struct zpci_aift *aift;
> +
>   	if (!gib)
>   		return;
> +	aift = kvm_s390_pci_get_aift();
> +	if (aift) {
> +		mutex_lock(&aift->lock);
> +		kvm_s390_pci_aen_exit();

Shouldn't we check for CONFIG_PCI and sclp.gas_aeni here as in gib_init ?

> +		mutex_unlock(&aift->lock);
> +	}
>   	chsc_sgib(0);
>   	unregister_adapter_interrupt(&gib_alert_irq);
>   	free_page((unsigned long)gib);
> @@ -3315,6 +3324,14 @@ 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..9cd3c8eb59e8 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 +504,8 @@ int kvm_arch_init(void *opaque)
>   		goto out;
>   	}
>   
> +	kvm_s390_pci_init();
> +
>   	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 ecfc458a5b39..f0e5386ff943 100644
> --- a/arch/s390/kvm/pci.c
> +++ b/arch/s390/kvm/pci.c
> @@ -10,6 +10,113 @@
>   #include <linux/kvm_host.h>
>   #include <linux/pci.h>
>   #include <asm/kvm_pci.h>
> +#include "pci.h"
> +
> +static 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);
> +}
> +
> +struct zpci_aift *kvm_s390_pci_get_aift(void)
> +{
> +	return &aift;
> +}
> +
> +/* Caller must hold the aift lock before calling this function */
> +void kvm_s390_pci_aen_exit(void)
> +{
> +	struct zpci_gaite *gait;
> +	unsigned long flags;
> +	struct airq_iv *sbv;
> +	struct kvm_zdev **gait_kzdev;
> +	int size;
> +
> +	/* Clear the GAIT and forwarding summary vector */
> +	__set_irq_noiib(SIC_SET_AENI_CONTROLS, 0);

Why don't we use the PCI ISC here?

...snip...

-- 
Pierre Morel
IBM Lab Boeblingen