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KVM: s390: pv: Add query interface

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

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Steffen 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: Christian Borntraeger <borntraeger@linux.ibm.com>
This commit is contained in:
Janosch Frank 2022-05-17 16:36:21 +00:00 committed by Christian Borntraeger
parent 38c218259d
commit 35d02493db
2 changed files with 101 additions and 0 deletions
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76
arch/s390/kvm/kvm-s390.c
View file

@ -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;
}

25
include/uapi/linux/kvm.h
View file

@ -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 {