From: Janosch Frank <frankja@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> Reviewed-by: Steffen Eiden <seiden@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220517163629.3443-4-frankja@xxxxxxxxxxxxx Message-Id: <20220517163629.3443-4-frankja@xxxxxxxxxxxxx> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx> --- arch/s390/kvm/kvm-s390.c | 76 ++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 25 +++++++++++++ 2 files changed, 101 insertions(+) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 76ad6408cb2c..5859f243d287 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -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; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 5088bd9f1922..5a5f66026dd3 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -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 { -- 2.35.1
