diff options
Diffstat (limited to 'arch/s390/kernel/uv.c')
| -rw-r--r-- | arch/s390/kernel/uv.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index a5425075dd25..f9810d2a267c 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -234,6 +234,32 @@ static int make_secure_pte(pte_t *ptep, unsigned long addr, return uvcb->rc == 0x10a ? -ENXIO : -EINVAL; } +/** + * should_export_before_import - Determine whether an export is needed + * before an import-like operation + * @uvcb: the Ultravisor control block of the UVC to be performed + * @mm: the mm of the process + * + * Returns whether an export is needed before every import-like operation. + * This is needed for shared pages, which don't trigger a secure storage + * exception when accessed from a different guest. + * + * Although considered as one, the Unpin Page UVC is not an actual import, + * so it is not affected. + * + * No export is needed also when there is only one protected VM, because the + * page cannot belong to the wrong VM in that case (there is no "other VM" + * it can belong to). + * + * Return: true if an export is needed before every import, otherwise false. + */ +static bool should_export_before_import(struct uv_cb_header *uvcb, struct mm_struct *mm) +{ + if (uvcb->cmd == UVC_CMD_UNPIN_PAGE_SHARED) + return false; + return atomic_read(&mm->context.protected_count) > 1; +} + /* * Requests the Ultravisor to make a page accessible to a guest. * If it's brought in the first time, it will be cleared. If @@ -277,6 +303,8 @@ again: lock_page(page); ptep = get_locked_pte(gmap->mm, uaddr, &ptelock); + if (should_export_before_import(uvcb, gmap->mm)) + uv_convert_from_secure(page_to_phys(page)); rc = make_secure_pte(ptep, uaddr, page, uvcb); pte_unmap_unlock(ptep, ptelock); unlock_page(page); @@ -334,6 +362,61 @@ int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr) } EXPORT_SYMBOL_GPL(gmap_convert_to_secure); +/** + * gmap_destroy_page - Destroy a guest page. + * @gmap: the gmap of the guest + * @gaddr: the guest address to destroy + * + * An attempt will be made to destroy the given guest page. If the attempt + * fails, an attempt is made to export the page. If both attempts fail, an + * appropriate error is returned. + */ +int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr) +{ + struct vm_area_struct *vma; + unsigned long uaddr; + struct page *page; + int rc; + + rc = -EFAULT; + mmap_read_lock(gmap->mm); + + uaddr = __gmap_translate(gmap, gaddr); + if (IS_ERR_VALUE(uaddr)) + goto out; + vma = vma_lookup(gmap->mm, uaddr); + if (!vma) + goto out; + /* + * Huge pages should not be able to become secure + */ + if (is_vm_hugetlb_page(vma)) + goto out; + + rc = 0; + /* we take an extra reference here */ + page = follow_page(vma, uaddr, FOLL_WRITE | FOLL_GET); + if (IS_ERR_OR_NULL(page)) + goto out; + rc = uv_destroy_owned_page(page_to_phys(page)); + /* + * Fault handlers can race; it is possible that two CPUs will fault + * on the same secure page. One CPU can destroy the page, reboot, + * re-enter secure mode and import it, while the second CPU was + * stuck at the beginning of the handler. At some point the second + * CPU will be able to progress, and it will not be able to destroy + * the page. In that case we do not want to terminate the process, + * we instead try to export the page. + */ + if (rc) + rc = uv_convert_owned_from_secure(page_to_phys(page)); + put_page(page); +out: + mmap_read_unlock(gmap->mm); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_destroy_page); + /* * To be called with the page locked or with an extra reference! This will * prevent gmap_make_secure from touching the page concurrently. Having 2 @@ -392,6 +475,54 @@ static ssize_t uv_query_facilities(struct kobject *kobj, static struct kobj_attribute uv_query_facilities_attr = __ATTR(facilities, 0444, uv_query_facilities, NULL); +static ssize_t uv_query_supp_se_hdr_ver(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lx\n", uv_info.supp_se_hdr_ver); +} + +static struct kobj_attribute uv_query_supp_se_hdr_ver_attr = + __ATTR(supp_se_hdr_ver, 0444, uv_query_supp_se_hdr_ver, NULL); + +static ssize_t uv_query_supp_se_hdr_pcf(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lx\n", uv_info.supp_se_hdr_pcf); +} + +static struct kobj_attribute uv_query_supp_se_hdr_pcf_attr = + __ATTR(supp_se_hdr_pcf, 0444, uv_query_supp_se_hdr_pcf, NULL); + +static ssize_t uv_query_dump_cpu_len(struct kobject *kobj, + struct kobj_attribute *attr, char *page) +{ + return scnprintf(page, PAGE_SIZE, "%lx\n", + uv_info.guest_cpu_stor_len); +} + +static struct kobj_attribute uv_query_dump_cpu_len_attr = + __ATTR(uv_query_dump_cpu_len, 0444, uv_query_dump_cpu_len, NULL); + +static ssize_t uv_query_dump_storage_state_len(struct kobject *kobj, + struct kobj_attribute *attr, char *page) +{ + return scnprintf(page, PAGE_SIZE, "%lx\n", + uv_info.conf_dump_storage_state_len); +} + +static struct kobj_attribute uv_query_dump_storage_state_len_attr = + __ATTR(dump_storage_state_len, 0444, uv_query_dump_storage_state_len, NULL); + +static ssize_t uv_query_dump_finalize_len(struct kobject *kobj, + struct kobj_attribute *attr, char *page) +{ + return scnprintf(page, PAGE_SIZE, "%lx\n", + uv_info.conf_dump_finalize_len); +} + +static struct kobj_attribute uv_query_dump_finalize_len_attr = + __ATTR(dump_finalize_len, 0444, uv_query_dump_finalize_len, NULL); + static ssize_t uv_query_feature_indications(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -431,12 +562,37 @@ static ssize_t uv_query_max_guest_addr(struct kobject *kobj, static struct kobj_attribute uv_query_max_guest_addr_attr = __ATTR(max_address, 0444, uv_query_max_guest_addr, NULL); +static ssize_t uv_query_supp_att_req_hdr_ver(struct kobject *kobj, + struct kobj_attribute *attr, char *page) +{ + return scnprintf(page, PAGE_SIZE, "%lx\n", uv_info.supp_att_req_hdr_ver); +} + +static struct kobj_attribute uv_query_supp_att_req_hdr_ver_attr = + __ATTR(supp_att_req_hdr_ver, 0444, uv_query_supp_att_req_hdr_ver, NULL); + +static ssize_t uv_query_supp_att_pflags(struct kobject *kobj, + struct kobj_attribute *attr, char *page) +{ + return scnprintf(page, PAGE_SIZE, "%lx\n", uv_info.supp_att_pflags); +} + +static struct kobj_attribute uv_query_supp_att_pflags_attr = + __ATTR(supp_att_pflags, 0444, uv_query_supp_att_pflags, NULL); + static struct attribute *uv_query_attrs[] = { &uv_query_facilities_attr.attr, &uv_query_feature_indications_attr.attr, &uv_query_max_guest_cpus_attr.attr, &uv_query_max_guest_vms_attr.attr, &uv_query_max_guest_addr_attr.attr, + &uv_query_supp_se_hdr_ver_attr.attr, + &uv_query_supp_se_hdr_pcf_attr.attr, + &uv_query_dump_storage_state_len_attr.attr, + &uv_query_dump_finalize_len_attr.attr, + &uv_query_dump_cpu_len_attr.attr, + &uv_query_supp_att_req_hdr_ver_attr.attr, + &uv_query_supp_att_pflags_attr.attr, NULL, }; |