Commit 35d02493 authored by Janosch Frank's avatar Janosch Frank Committed by Christian Borntraeger
Browse files

KVM: s390: pv: Add query interface 



Some of the query information is already available via sysfs but
having a IOCTL makes the information easier to retrieve.

Signed-off-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: default avatarSteffen Eiden <seiden@linux.ibm.com>
Link: https://lore.kernel.org/r/20220517163629.3443-4-frankja@linux.ibm.com


Message-Id: <20220517163629.3443-4-frankja@linux.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@linux.ibm.com>
parent 38c21825

arch/s390/kvm/kvm-s390.c

+76 −0
Original line number Diff line number Diff line
@@ -2224,6 +2224,42 @@ static int kvm_s390_cpus_to_pv(struct kvm *kvm, u16 *rc, u16 *rrc) 
	return r;

}



/*

 * Here we provide user space with a direct interface to query UV

 * related data like UV maxima and available features as well as

 * feature specific data.

 *

 * To facilitate future extension of the data structures we'll try to

 * write data up to the maximum requested length.

 */

static ssize_t kvm_s390_handle_pv_info(struct kvm_s390_pv_info *info)

{

	ssize_t len_min;



	switch (info->header.id) {

	case KVM_PV_INFO_VM: {

		len_min =  sizeof(info->header) + sizeof(info->vm);



		if (info->header.len_max < len_min)

			return -EINVAL;



		memcpy(info->vm.inst_calls_list,

		       uv_info.inst_calls_list,

		       sizeof(uv_info.inst_calls_list));



		/* It's max cpuid not max cpus, so it's off by one */

		info->vm.max_cpus = uv_info.max_guest_cpu_id + 1;

		info->vm.max_guests = uv_info.max_num_sec_conf;

		info->vm.max_guest_addr = uv_info.max_sec_stor_addr;

		info->vm.feature_indication = uv_info.uv_feature_indications;



		return len_min;

	}

	default:

		return -EINVAL;

	}

}



static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)

{

	int r = 0;
@@ -2360,6 +2396,46 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd) 
			     cmd->rc, cmd->rrc);

		break;

	}

	case KVM_PV_INFO: {

		struct kvm_s390_pv_info info = {};

		ssize_t data_len;



		/*

		 * No need to check the VM protection here.

		 *

		 * Maybe user space wants to query some of the data

		 * when the VM is still unprotected. If we see the

		 * need to fence a new data command we can still

		 * return an error in the info handler.

		 */



		r = -EFAULT;

		if (copy_from_user(&info, argp, sizeof(info.header)))

			break;



		r = -EINVAL;

		if (info.header.len_max < sizeof(info.header))

			break;



		data_len = kvm_s390_handle_pv_info(&info);

		if (data_len < 0) {

			r = data_len;

			break;

		}

		/*

		 * If a data command struct is extended (multiple

		 * times) this can be used to determine how much of it

		 * is valid.

		 */

		info.header.len_written = data_len;



		r = -EFAULT;

		if (copy_to_user(argp, &info, data_len))

			break;



		r = 0;

		break;

	}

	default:

		r = -ENOTTY;

	}

include/uapi/linux/kvm.h

+25 −0
Original line number Diff line number Diff line
@@ -1660,6 +1660,30 @@ struct kvm_s390_pv_unp { 
	__u64 tweak;

};



enum pv_cmd_info_id {

	KVM_PV_INFO_VM,

};



struct kvm_s390_pv_info_vm {

	__u64 inst_calls_list[4];

	__u64 max_cpus;

	__u64 max_guests;

	__u64 max_guest_addr;

	__u64 feature_indication;

};



struct kvm_s390_pv_info_header {

	__u32 id;

	__u32 len_max;

	__u32 len_written;

	__u32 reserved;

};



struct kvm_s390_pv_info {

	struct kvm_s390_pv_info_header header;

	struct kvm_s390_pv_info_vm vm;

};



enum pv_cmd_id {

	KVM_PV_ENABLE,

	KVM_PV_DISABLE,
@@ -1668,6 +1692,7 @@ enum pv_cmd_id { 
	KVM_PV_VERIFY,

	KVM_PV_PREP_RESET,

	KVM_PV_UNSHARE_ALL,

	KVM_PV_INFO,

};



struct kvm_pv_cmd {