Commit 8aba0958 authored by Janosch Frank's avatar Janosch Frank Committed by Christian Borntraeger
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KVM: s390: Add CPU dump functionality 



The previous patch introduced the per-VM dump functions now let's
focus on dumping the VCPU state via the newly introduced
KVM_S390_PV_CPU_COMMAND ioctl which mirrors the VM UV ioctl and can be
extended with new commands later.

Signed-off-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20220517163629.3443-8-frankja@linux.ibm.com


Message-Id: <20220517163629.3443-8-frankja@linux.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@linux.ibm.com>
parent 0460eb35

arch/s390/kvm/kvm-s390.c

+69 −0
Original line number Diff line number Diff line
@@ -5096,6 +5096,48 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp, 
	return -ENOIOCTLCMD;

}



static int kvm_s390_handle_pv_vcpu_dump(struct kvm_vcpu *vcpu,

					struct kvm_pv_cmd *cmd)

{

	struct kvm_s390_pv_dmp dmp;

	void *data;

	int ret;



	/* Dump initialization is a prerequisite */

	if (!vcpu->kvm->arch.pv.dumping)

		return -EINVAL;



	if (copy_from_user(&dmp, (__u8 __user *)cmd->data, sizeof(dmp)))

		return -EFAULT;



	/* We only handle this subcmd right now */

	if (dmp.subcmd != KVM_PV_DUMP_CPU)

		return -EINVAL;



	/* CPU dump length is the same as create cpu storage donation. */

	if (dmp.buff_len != uv_info.guest_cpu_stor_len)

		return -EINVAL;



	data = kvzalloc(uv_info.guest_cpu_stor_len, GFP_KERNEL);

	if (!data)

		return -ENOMEM;



	ret = kvm_s390_pv_dump_cpu(vcpu, data, &cmd->rc, &cmd->rrc);



	VCPU_EVENT(vcpu, 3, "PROTVIRT DUMP CPU %d rc %x rrc %x",

		   vcpu->vcpu_id, cmd->rc, cmd->rrc);



	if (ret)

		ret = -EINVAL;



	/* On success copy over the dump data */

	if (!ret && copy_to_user((__u8 __user *)dmp.buff_addr, data, uv_info.guest_cpu_stor_len))

		ret = -EFAULT;



	kvfree(data);

	return ret;

}



long kvm_arch_vcpu_ioctl(struct file *filp,

			 unsigned int ioctl, unsigned long arg)

{
@@ -5260,6 +5302,33 @@ long kvm_arch_vcpu_ioctl(struct file *filp, 
					   irq_state.len);

		break;

	}

	case KVM_S390_PV_CPU_COMMAND: {

		struct kvm_pv_cmd cmd;



		r = -EINVAL;

		if (!is_prot_virt_host())

			break;



		r = -EFAULT;

		if (copy_from_user(&cmd, argp, sizeof(cmd)))

			break;



		r = -EINVAL;

		if (cmd.flags)

			break;



		/* We only handle this cmd right now */

		if (cmd.cmd != KVM_PV_DUMP)

			break;



		r = kvm_s390_handle_pv_vcpu_dump(vcpu, &cmd);



		/* Always copy over UV rc / rrc data */

		if (copy_to_user((__u8 __user *)argp, &cmd.rc,

				 sizeof(cmd.rc) + sizeof(cmd.rrc)))

			r = -EFAULT;

		break;

	}

	default:

		r = -ENOTTY;

	}

arch/s390/kvm/kvm-s390.h

+1 −0
Original line number Diff line number Diff line
@@ -250,6 +250,7 @@ int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc, 
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);

int kvm_s390_pv_dump_cpu(struct kvm_vcpu *vcpu, void *buff, u16 *rc, u16 *rrc);

int kvm_s390_pv_dump_stor_state(struct kvm *kvm, void __user *buff_user,

				u64 *gaddr, u64 buff_user_len, u16 *rc, u16 *rrc);

int kvm_s390_pv_dump_complete(struct kvm *kvm, void __user *buff_user,

arch/s390/kvm/pv.c

+16 −0
Original line number Diff line number Diff line
@@ -300,6 +300,22 @@ int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state) 
	return 0;

}



int kvm_s390_pv_dump_cpu(struct kvm_vcpu *vcpu, void *buff, u16 *rc, u16 *rrc)

{

	struct uv_cb_dump_cpu uvcb = {

		.header.cmd = UVC_CMD_DUMP_CPU,

		.header.len = sizeof(uvcb),

		.cpu_handle = vcpu->arch.pv.handle,

		.dump_area_origin = (u64)buff,

	};

	int cc;



	cc = uv_call_sched(0, (u64)&uvcb);

	*rc = uvcb.header.rc;

	*rrc = uvcb.header.rrc;

	return cc;

}



/* Size of the cache for the storage state dump data. 1MB for now */

#define DUMP_BUFF_LEN HPAGE_SIZE

include/uapi/linux/kvm.h

+4 −0
Original line number Diff line number Diff line
@@ -1664,6 +1664,7 @@ enum pv_cmd_dmp_id { 
	KVM_PV_DUMP_INIT,

	KVM_PV_DUMP_CONFIG_STOR_STATE,

	KVM_PV_DUMP_COMPLETE,

	KVM_PV_DUMP_CPU,

};



struct kvm_s390_pv_dmp {
@@ -2168,4 +2169,7 @@ struct kvm_stats_desc { 
/* Available with KVM_CAP_XSAVE2 */

#define KVM_GET_XSAVE2		  _IOR(KVMIO,  0xcf, struct kvm_xsave)



/* Available with KVM_CAP_S390_PROTECTED_DUMP */

#define KVM_S390_PV_CPU_COMMAND	_IOWR(KVMIO, 0xd0, struct kvm_pv_cmd)



#endif /* __LINUX_KVM_H */