From patchwork Fri Jun 3 06:56:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudio Imbrenda X-Patchwork-Id: 12868654 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 486B1CCA480 for ; Fri, 3 Jun 2022 06:57:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241800AbiFCG5F (ORCPT ); Fri, 3 Jun 2022 02:57:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240244AbiFCG5D (ORCPT ); Fri, 3 Jun 2022 02:57:03 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4553F2B; Thu, 2 Jun 2022 23:56:54 -0700 (PDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 2535N0oP007408; Fri, 3 Jun 2022 06:56:54 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=yKcdEiqK3UwGu4J10SwUpD0w7aypCEE6Zop823vNxRw=; b=UT45aHXj0AoXzFopUmVF1yrTM9bCx7rEJnEyxLjeDo/5sTLI+W/phqXXvWuEC5fcOGLx aNHTlgo8IJidlTqJaKhMZBGIyN6Yf3avY6g4yiTMb+LIY1vbrnNdHYPoDnpr27o9NPx5 mPEJc0P8RvHWjD1Qi/FZHhzsQ8QgdUdYgxwqg79RDJAH9P2LmfChadcxlitb8gW0zQE+ 2yc5AGf1M+KVk2iXW5H80Ck20yeMhF5XeF9ALdTtOIymq9I87UKfTJJInvVre6HUd8vf V6pvf7I98NtTTuDkUQ/OC/EUC5N/Q69P5mI3eFm0b5Uas+BHJJycDAxB8iL4ihFjkD89 Nw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3gfc3usf32-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jun 2022 06:56:54 +0000 Received: from m0098394.ppops.net (m0098394.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 2536WFXn011132; Fri, 3 Jun 2022 06:56:53 GMT Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3gfc3usf2f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jun 2022 06:56:53 +0000 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 2536p6pY007332; Fri, 3 Jun 2022 06:56:51 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma03ams.nl.ibm.com with ESMTP id 3gbc7h81x4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jun 2022 06:56:51 +0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 2536umwp20709780 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 3 Jun 2022 06:56:48 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 13EAA4203F; Fri, 3 Jun 2022 06:56:48 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9ED2B42042; Fri, 3 Jun 2022 06:56:47 +0000 (GMT) Received: from p-imbrenda.boeblingen.de.ibm.com (unknown [9.152.224.40]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 3 Jun 2022 06:56:47 +0000 (GMT) From: Claudio Imbrenda To: kvm@vger.kernel.org Cc: borntraeger@de.ibm.com, frankja@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, scgl@linux.ibm.com, mimu@linux.ibm.com, nrb@linux.ibm.com Subject: [PATCH v11 04/19] KVM: s390: pv: refactor s390_reset_acc Date: Fri, 3 Jun 2022 08:56:30 +0200 Message-Id: <20220603065645.10019-5-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220603065645.10019-1-imbrenda@linux.ibm.com> References: <20220603065645.10019-1-imbrenda@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: qiAJehGUYy56EMhtnYg9gXjE-Y7eFTYf X-Proofpoint-GUID: 0IXy4Ldhj-PYGawxcQo_5hSTXRCa6MPA X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.517,FMLib:17.11.64.514 definitions=2022-06-03_01,2022-06-02_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 mlxlogscore=992 priorityscore=1501 spamscore=0 bulkscore=0 suspectscore=0 phishscore=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 impostorscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2204290000 definitions=main-2206030027 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Refactor s390_reset_acc so that it can be reused in upcoming patches. We don't want to hold all the locks used in a walk_page_range for too long, and the destroy page UVC does take some time to complete. Therefore we quickly gather the pages to destroy, and then destroy them without holding all the locks. The new refactored function optionally allows to return early without completing if a fatal signal is pending (and return and appropriate error code). Two wrappers are provided to call the new function. Signed-off-by: Claudio Imbrenda Reviewed-by: Janosch Frank Reviewed-by: Nico Boehr --- arch/s390/include/asm/gmap.h | 37 +++++++++++++- arch/s390/kvm/pv.c | 12 ++++- arch/s390/mm/gmap.c | 95 +++++++++++++++++++++++++----------- 3 files changed, 112 insertions(+), 32 deletions(-) diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h index f4073106e1f3..21ae3b3c3bb5 100644 --- a/arch/s390/include/asm/gmap.h +++ b/arch/s390/include/asm/gmap.h @@ -147,7 +147,42 @@ int gmap_mprotect_notify(struct gmap *, unsigned long start, void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long dirty_bitmap[4], unsigned long gaddr, unsigned long vmaddr); int gmap_mark_unmergeable(void); -void s390_reset_acc(struct mm_struct *mm); void s390_unlist_old_asce(struct gmap *gmap); int s390_replace_asce(struct gmap *gmap); +void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns); +int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start, + unsigned long end, bool interruptible); + +/** + * s390_uv_destroy_range - Destroy a range of pages in the given mm. + * @mm the mm on which to operate on + * @start the start of the range + * @end the end of the range + * + * This function will call cond_sched, so it should not generate stalls, but + * it will otherwise only return when it completed. + */ +static inline void s390_uv_destroy_range(struct mm_struct *mm, unsigned long start, + unsigned long end) +{ + (void)__s390_uv_destroy_range(mm, start, end, false); +} + +/** + * s390_uv_destroy_range_interruptible - Destroy a range of pages in the + * given mm, but stop when a fatal signal is received. + * @mm the mm on which to operate on + * @start the start of the range + * @end the end of the range + * + * This function will call cond_sched, so it should not generate stalls. If + * a fatal signal is received, it will return with -EINTR immediately, + * without finishing destroying the whole range. Upon successful + * completion, 0 is returned. + */ +static inline int s390_uv_destroy_range_interruptible(struct mm_struct *mm, unsigned long start, + unsigned long end) +{ + return __s390_uv_destroy_range(mm, start, end, true); +} #endif /* _ASM_S390_GMAP_H */ diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 8eee3fc414e5..bcbe10862f9f 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include "kvm-s390.h" int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) @@ -152,8 +154,14 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc) { int cc; - /* make all pages accessible before destroying the guest */ - s390_reset_acc(kvm->mm); + /* + * if the mm still has a mapping, make all its pages accessible + * before destroying the guest + */ + if (mmget_not_zero(kvm->mm)) { + s390_uv_destroy_range(kvm->mm, 0, TASK_SIZE); + mmput(kvm->mm); + } cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm), UVC_CMD_DESTROY_SEC_CONF, rc, rrc); diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index bd07157f834f..653b97053d5e 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2683,44 +2683,81 @@ void s390_reset_cmma(struct mm_struct *mm) } EXPORT_SYMBOL_GPL(s390_reset_cmma); -/* - * make inaccessible pages accessible again - */ -static int __s390_reset_acc(pte_t *ptep, unsigned long addr, - unsigned long next, struct mm_walk *walk) +#define GATHER_GET_PAGES 32 + +struct reset_walk_state { + unsigned long next; + unsigned long count; + unsigned long pfns[GATHER_GET_PAGES]; +}; + +static int s390_gather_pages(pte_t *ptep, unsigned long addr, + unsigned long next, struct mm_walk *walk) { + struct reset_walk_state *p = walk->private; pte_t pte = READ_ONCE(*ptep); - /* There is a reference through the mapping */ - if (pte_present(pte)) - WARN_ON_ONCE(uv_destroy_owned_page(pte_val(pte) & PAGE_MASK)); - - return 0; + if (pte_present(pte)) { + /* we have a reference from the mapping, take an extra one */ + get_page(phys_to_page(pte_val(pte))); + p->pfns[p->count] = phys_to_pfn(pte_val(pte)); + p->next = next; + p->count++; + } + return p->count >= GATHER_GET_PAGES; } -static const struct mm_walk_ops reset_acc_walk_ops = { - .pte_entry = __s390_reset_acc, +static const struct mm_walk_ops gather_pages_ops = { + .pte_entry = s390_gather_pages, }; -#include -void s390_reset_acc(struct mm_struct *mm) +/* + * Call the Destroy secure page UVC on each page in the given array of PFNs. + * Each page needs to have an extra reference, which will be released here. + */ +void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns) { - if (!mm_is_protected(mm)) - return; - /* - * we might be called during - * reset: we walk the pages and clear - * close of all kvm file descriptors: we walk the pages and clear - * exit of process on fd closure: vma already gone, do nothing - */ - if (!mmget_not_zero(mm)) - return; - mmap_read_lock(mm); - walk_page_range(mm, 0, TASK_SIZE, &reset_acc_walk_ops, NULL); - mmap_read_unlock(mm); - mmput(mm); + unsigned long i; + + for (i = 0; i < count; i++) { + /* we always have an extra reference */ + uv_destroy_owned_page(pfn_to_phys(pfns[i])); + /* get rid of the extra reference */ + put_page(pfn_to_page(pfns[i])); + cond_resched(); + } +} +EXPORT_SYMBOL_GPL(s390_uv_destroy_pfns); + +/** + * __s390_uv_destroy_range - Walk the given range of the given address + * space, and call the destroy secure page UVC on each page. + * Optionally exit early if a fatal signal is pending. + * @mm the mm to operate on + * @start the start of the range + * @end the end of the range + * @interruptible if not 0, stop when a fatal signal is received + * Return: 0 on success, -EINTR if the function stopped before completing + */ +int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start, + unsigned long end, bool interruptible) +{ + struct reset_walk_state state = { .next = start }; + int r = 1; + + while (r > 0) { + state.count = 0; + mmap_read_lock(mm); + r = walk_page_range(mm, state.next, end, &gather_pages_ops, &state); + mmap_read_unlock(mm); + cond_resched(); + s390_uv_destroy_pfns(state.count, state.pfns); + if (interruptible && fatal_signal_pending(current)) + return -EINTR; + } + return 0; } -EXPORT_SYMBOL_GPL(s390_reset_acc); +EXPORT_SYMBOL_GPL(__s390_uv_destroy_range); /** * s390_unlist_old_asce - Remove the topmost level of page tables from the