Commit 7de3f142 authored by Janosch Frank's avatar Janosch Frank Committed by Christian Borntraeger
Browse files

KVM: s390: Add new reset vcpu API 



The architecture states that we need to reset local IRQs for all CPU
resets. Because the old reset interface did not support the normal CPU
reset we never did that on a normal reset.

Let's implement an interface for the missing normal and clear resets
and reset all local IRQs, registers and control structures as stated
in the architecture.

Userspace might already reset the registers via the vcpu run struct,
but as we need the interface for the interrupt clearing part anyway,
we implement the resets fully and don't rely on userspace to reset the
rest.

Signed-off-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: default avatarThomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20200131100205.74720-4-frankja@linux.ibm.com


Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent cca00ebb

Documentation/virt/kvm/api.txt

+43 −0
Original line number Diff line number Diff line
@@ -4168,6 +4168,42 @@ This ioctl issues an ultravisor call to terminate the secure guest, 
unpins the VPA pages and releases all the device pages that are used to

track the secure pages by hypervisor.



4.122 KVM_S390_NORMAL_RESET



Capability: KVM_CAP_S390_VCPU_RESETS

Architectures: s390

Type: vcpu ioctl

Parameters: none

Returns: 0



This ioctl resets VCPU registers and control structures according to

the cpu reset definition in the POP (Principles Of Operation).



4.123 KVM_S390_INITIAL_RESET



Capability: none

Architectures: s390

Type: vcpu ioctl

Parameters: none

Returns: 0



This ioctl resets VCPU registers and control structures according to

the initial cpu reset definition in the POP. However, the cpu is not

put into ESA mode. This reset is a superset of the normal reset.



4.124 KVM_S390_CLEAR_RESET



Capability: KVM_CAP_S390_VCPU_RESETS

Architectures: s390

Type: vcpu ioctl

Parameters: none

Returns: 0



This ioctl resets VCPU registers and control structures according to

the clear cpu reset definition in the POP. However, the cpu is not put

into ESA mode. This reset is a superset of the initial reset.





5. The kvm_run structure

------------------------
@@ -5396,3 +5432,10 @@ handling by KVM (as some KVM hypercall may be mistakenly treated as TLB 
flush hypercalls by Hyper-V) so userspace should disable KVM identification

in CPUID and only exposes Hyper-V identification. In this case, guest

thinks it's running on Hyper-V and only use Hyper-V hypercalls.



8.22 KVM_CAP_S390_VCPU_RESETS



Architectures: s390



This capability indicates that the KVM_S390_NORMAL_RESET and

KVM_S390_CLEAR_RESET ioctls are available.

arch/s390/kvm/kvm-s390.c

+57 −27
Original line number Diff line number Diff line
@@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) 
	case KVM_CAP_S390_CMMA_MIGRATION:

	case KVM_CAP_S390_AIS:

	case KVM_CAP_S390_AIS_MIGRATION:

	case KVM_CAP_S390_VCPU_RESETS:

		r = 1;

		break;

	case KVM_CAP_S390_HPAGE_1M:
@@ -2844,29 +2845,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) 


}



static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)

{

	/* this equals initial cpu reset in pop, but we don't switch to ESA */

	vcpu->arch.sie_block->gpsw.mask = 0;

	vcpu->arch.sie_block->gpsw.addr = 0;

	kvm_s390_set_prefix(vcpu, 0);

	kvm_s390_set_cpu_timer(vcpu, 0);

	vcpu->arch.sie_block->ckc = 0;

	vcpu->arch.sie_block->todpr = 0;

	memset(vcpu->arch.sie_block->gcr, 0, sizeof(vcpu->arch.sie_block->gcr));

	vcpu->arch.sie_block->gcr[0] = CR0_INITIAL_MASK;

	vcpu->arch.sie_block->gcr[14] = CR14_INITIAL_MASK;

	vcpu->run->s.regs.fpc = 0;

	vcpu->arch.sie_block->gbea = 1;

	vcpu->arch.sie_block->pp = 0;

	vcpu->arch.sie_block->fpf &= ~FPF_BPBC;

	vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;

	kvm_clear_async_pf_completion_queue(vcpu);

	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))

		kvm_s390_vcpu_stop(vcpu);

	kvm_s390_clear_local_irqs(vcpu);

}



void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)

{

	mutex_lock(&vcpu->kvm->lock);
@@ -3281,10 +3259,53 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, 
	return r;

}



static int kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)

static void kvm_arch_vcpu_ioctl_normal_reset(struct kvm_vcpu *vcpu)

{

	kvm_s390_vcpu_initial_reset(vcpu);

	return 0;

	vcpu->arch.sie_block->gpsw.mask &= ~PSW_MASK_RI;

	vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;

	memset(vcpu->run->s.regs.riccb, 0, sizeof(vcpu->run->s.regs.riccb));



	kvm_clear_async_pf_completion_queue(vcpu);

	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))

		kvm_s390_vcpu_stop(vcpu);

	kvm_s390_clear_local_irqs(vcpu);

}



static void kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)

{

	/* Initial reset is a superset of the normal reset */

	kvm_arch_vcpu_ioctl_normal_reset(vcpu);



	/* this equals initial cpu reset in pop, but we don't switch to ESA */

	vcpu->arch.sie_block->gpsw.mask = 0;

	vcpu->arch.sie_block->gpsw.addr = 0;

	kvm_s390_set_prefix(vcpu, 0);

	kvm_s390_set_cpu_timer(vcpu, 0);

	vcpu->arch.sie_block->ckc = 0;

	vcpu->arch.sie_block->todpr = 0;

	memset(vcpu->arch.sie_block->gcr, 0, sizeof(vcpu->arch.sie_block->gcr));

	vcpu->arch.sie_block->gcr[0] = CR0_INITIAL_MASK;

	vcpu->arch.sie_block->gcr[14] = CR14_INITIAL_MASK;

	vcpu->run->s.regs.fpc = 0;

	vcpu->arch.sie_block->gbea = 1;

	vcpu->arch.sie_block->pp = 0;

	vcpu->arch.sie_block->fpf &= ~FPF_BPBC;

}



static void kvm_arch_vcpu_ioctl_clear_reset(struct kvm_vcpu *vcpu)

{

	struct kvm_sync_regs *regs = &vcpu->run->s.regs;



	/* Clear reset is a superset of the initial reset */

	kvm_arch_vcpu_ioctl_initial_reset(vcpu);



	memset(&regs->gprs, 0, sizeof(regs->gprs));

	memset(&regs->vrs, 0, sizeof(regs->vrs));

	memset(&regs->acrs, 0, sizeof(regs->acrs));

	memset(&regs->gscb, 0, sizeof(regs->gscb));



	regs->etoken = 0;

	regs->etoken_extension = 0;

}



int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
@@ -4357,8 +4378,17 @@ long kvm_arch_vcpu_ioctl(struct file *filp, 
		r = kvm_arch_vcpu_ioctl_set_initial_psw(vcpu, psw);

		break;

	}

	case KVM_S390_CLEAR_RESET:

		r = 0;

		kvm_arch_vcpu_ioctl_clear_reset(vcpu);

		break;

	case KVM_S390_INITIAL_RESET:

		r = kvm_arch_vcpu_ioctl_initial_reset(vcpu);

		r = 0;

		kvm_arch_vcpu_ioctl_initial_reset(vcpu);

		break;

	case KVM_S390_NORMAL_RESET:

		r = 0;

		kvm_arch_vcpu_ioctl_normal_reset(vcpu);

		break;

	case KVM_SET_ONE_REG:

	case KVM_GET_ONE_REG: {

include/uapi/linux/kvm.h

+5 −0
Original line number Diff line number Diff line
@@ -1009,6 +1009,7 @@ struct kvm_ppc_resize_hpt { 
#define KVM_CAP_PPC_GUEST_DEBUG_SSTEP 176

#define KVM_CAP_ARM_NISV_TO_USER 177

#define KVM_CAP_ARM_INJECT_EXT_DABT 178

#define KVM_CAP_S390_VCPU_RESETS 179



#ifdef KVM_CAP_IRQ_ROUTING
@@ -1473,6 +1474,10 @@ struct kvm_enc_region { 
/* Available with KVM_CAP_ARM_SVE */

#define KVM_ARM_VCPU_FINALIZE	  _IOW(KVMIO,  0xc2, int)



/* Available with  KVM_CAP_S390_VCPU_RESETS */

#define KVM_S390_NORMAL_RESET	_IO(KVMIO,   0xc3)

#define KVM_S390_CLEAR_RESET	_IO(KVMIO,   0xc4)



/* Secure Encrypted Virtualization command */

enum sev_cmd_id {

	/* Guest initialization commands */

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