Re: [PATCH v2 31/42] KVM: s390: protvirt: Report CPU state to Ultravisor

[David Hildenbrand <david@redhat.com>]

On 14.02.20 23:26, Christian Borntraeger wrote:
> From: Janosch Frank <frankja@linux.ibm.com>
> 
> VCPU states have to be reported to the ultravisor for SIGP
> interpretation, kdump, kexec and reboot.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> [borntraeger@de.ibm.com: patch merging, splitting, fixing]
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/include/asm/uv.h | 15 +++++++++++++++
>  arch/s390/kvm/kvm-s390.c   |  7 ++++++-
>  arch/s390/kvm/kvm-s390.h   |  2 ++
>  arch/s390/kvm/pv.c         | 22 ++++++++++++++++++++++
>  4 files changed, 45 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
> index 254d5769d136..7b82881ec3b4 100644
> --- a/arch/s390/include/asm/uv.h
> +++ b/arch/s390/include/asm/uv.h
> @@ -37,6 +37,7 @@
>  #define UVC_CMD_UNPACK_IMG		0x0301
>  #define UVC_CMD_VERIFY_IMG		0x0302
>  #define UVC_CMD_PREPARE_RESET		0x0320
> +#define UVC_CMD_CPU_SET_STATE		0x0330
>  #define UVC_CMD_SET_UNSHARE_ALL		0x0340
>  #define UVC_CMD_PIN_PAGE_SHARED		0x0341
>  #define UVC_CMD_UNPIN_PAGE_SHARED	0x0342
> @@ -58,6 +59,7 @@ enum uv_cmds_inst {
>  	BIT_UVC_CMD_SET_SEC_PARMS = 11,
>  	BIT_UVC_CMD_UNPACK_IMG = 13,
>  	BIT_UVC_CMD_VERIFY_IMG = 14,
> +	BIT_UVC_CMD_CPU_SET_STATE = 17,
>  	BIT_UVC_CMD_PREPARE_RESET = 18,
>  	BIT_UVC_CMD_UNSHARE_ALL = 20,
>  	BIT_UVC_CMD_PIN_PAGE_SHARED = 21,
> @@ -164,6 +166,19 @@ struct uv_cb_unp {
>  	u64 reserved38[3];
>  } __packed __aligned(8);
>  
> +#define PV_CPU_STATE_OPR	1
> +#define PV_CPU_STATE_STP	2
> +#define PV_CPU_STATE_CHKSTP	3
> +
> +struct uv_cb_cpu_set_state {
> +	struct uv_cb_header header;
> +	u64 reserved08[2];
> +	u64 cpu_handle;
> +	u8  reserved20[7];
> +	u8  state;
> +	u64 reserved28[5];
> +};
> +
>  /*
>   * A common UV call struct for calls that take no payload
>   * Examples:
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index ad84c1144908..5426b01e3da1 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -4396,6 +4396,7 @@ static void __enable_ibs_on_vcpu(struct kvm_vcpu *vcpu)
>  void kvm_s390_vcpu_start(struct kvm_vcpu *vcpu)
>  {
>  	int i, online_vcpus, started_vcpus = 0;
> +	u16 rc, rrc;
>  
>  	if (!is_vcpu_stopped(vcpu))
>  		return;
> @@ -4421,7 +4422,8 @@ void kvm_s390_vcpu_start(struct kvm_vcpu *vcpu)
>  		 */
>  		__disable_ibs_on_all_vcpus(vcpu->kvm);
>  	}
> -
> +	/* Let's tell the UV that we want to start again */
> +	kvm_s390_pv_set_cpu_state(vcpu, PV_CPU_STATE_OPR, &rc, &rrc);
>  	kvm_s390_clear_cpuflags(vcpu, CPUSTAT_STOPPED);
>  	/*
>  	 * Another VCPU might have used IBS while we were offline.
> @@ -4436,6 +4438,7 @@ void kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu)
>  {
>  	int i, online_vcpus, started_vcpus = 0;
>  	struct kvm_vcpu *started_vcpu = NULL;
> +	u16 rc, rrc;
>  
>  	if (is_vcpu_stopped(vcpu))
>  		return;
> @@ -4449,6 +4452,8 @@ void kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu)
>  	kvm_s390_clear_stop_irq(vcpu);
>  
>  	kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOPPED);
> +	/* Let's tell the UV that we successfully stopped the vcpu */
> +	kvm_s390_pv_set_cpu_state(vcpu, PV_CPU_STATE_STP, &rc, &rrc);
>  	__disable_ibs_on_vcpu(vcpu);
>  
>  	for (i = 0; i < online_vcpus; i++) {
> diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
> index d5503dd0d1e4..1af1e30beead 100644
> --- a/arch/s390/kvm/kvm-s390.h
> +++ b/arch/s390/kvm/kvm-s390.h
> @@ -218,6 +218,8 @@ int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
>  			      u16 *rrc);
>  int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size,
>  		       unsigned long tweak, u16 *rc, u16 *rrc);
> +int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state, u16 *rc,
> +			      u16 *rrc);
>  
>  static inline bool kvm_s390_pv_is_protected(struct kvm *kvm)
>  {
> diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
> index 80169a9b43ec..b4bf6b6eb708 100644
> --- a/arch/s390/kvm/pv.c
> +++ b/arch/s390/kvm/pv.c
> @@ -271,3 +271,25 @@ int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size,
>  		KVM_UV_EVENT(kvm, 3, "%s", "PROTVIRT VM UNPACK: successful");
>  	return ret;
>  }
> +
> +int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state, u16 *rc,
> +			      u16 *rrc)
> +{
> +	struct uv_cb_cpu_set_state uvcb = {
> +		.header.cmd	= UVC_CMD_CPU_SET_STATE,
> +		.header.len	= sizeof(uvcb),
> +		.cpu_handle	= kvm_s390_pv_handle_cpu(vcpu),
> +		.state		= state,
> +	};
> +	int cc;
> +
> +	if (!kvm_s390_pv_handle_cpu(vcpu))

I'd actually prefer to move this to the caller. (and sue the _protected
variant)

> +		return -EINVAL;
> +
> +	cc = uv_call(0, (u64)&uvcb);
> +	*rc = uvcb.header.rc;
> +	*rrc = uvcb.header.rrc;
> +	if (cc)
> +		return -EINVAL;

All return values are ignored. warn instead and make this a void function?

> +	return 0;
> +}
> 



-- 
Thanks,

David / dhildenb