From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:4298 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727686AbgBTKka (ORCPT ); Thu, 20 Feb 2020 05:40:30 -0500 From: Christian Borntraeger Subject: [PATCH v3 12/37] KVM: s390/mm: Make pages accessible before destroying the guest Date: Thu, 20 Feb 2020 05:39:55 -0500 Message-Id: <20200220104020.5343-13-borntraeger@de.ibm.com> In-Reply-To: <20200220104020.5343-1-borntraeger@de.ibm.com> References: <20200220104020.5343-1-borntraeger@de.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Christian Borntraeger , Janosch Frank Cc: KVM , Cornelia Huck , David Hildenbrand , Thomas Huth , Ulrich Weigand , Claudio Imbrenda , linux-s390 , Michael Mueller , Vasily Gorbik Before we destroy the secure configuration, we better make all pages accessible again. This also happens during reboot, where we reboot into a non-secure guest that then can go again into secure mode. As this "new" secure guest will have a new ID we cannot reuse the old page state. Signed-off-by: Christian Borntraeger Reviewed-by: Thomas Huth Reviewed-by: Cornelia Huck Reviewed-by: David Hildenbrand --- arch/s390/include/asm/gmap.h | 1 + arch/s390/kvm/pv.c | 2 ++ arch/s390/mm/gmap.c | 35 +++++++++++++++++++++++++++++++++++ 3 files changed, 38 insertions(+) diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h index 6f9ff7a69fa2..a816fb4734b8 100644 --- a/arch/s390/include/asm/gmap.h +++ b/arch/s390/include/asm/gmap.h @@ -149,4 +149,5 @@ 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); #endif /* _ASM_S390_GMAP_H */ diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 67ea9a18ed8f..7d95d7437140 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -66,6 +66,8 @@ int kvm_s390_pv_destroy_vm(struct kvm *kvm, u16 *rc, u16 *rrc) { int cc; + /* make all pages accessible before destroying the guest */ + s390_reset_acc(kvm->mm); cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm), UVC_CMD_DESTROY_SEC_CONF, rc, rrc); WRITE_ONCE(kvm->arch.gmap->guest_handle, 0); diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 7291452fe5f0..27926a06df32 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2650,3 +2650,38 @@ void s390_reset_cmma(struct mm_struct *mm) up_write(&mm->mmap_sem); } 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) +{ + pte_t pte = READ_ONCE(*ptep); + + if (pte_present(pte)) + WARN_ON_ONCE(uv_convert_from_secure(pte_val(pte) & PAGE_MASK)); + return 0; +} + +static const struct mm_walk_ops reset_acc_walk_ops = { + .pte_entry = __s390_reset_acc, +}; + +#include +void s390_reset_acc(struct mm_struct *mm) +{ + /* + * 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; + down_read(&mm->mmap_sem); + walk_page_range(mm, 0, TASK_SIZE, &reset_acc_walk_ops, NULL); + up_read(&mm->mmap_sem); + mmput(mm); +} +EXPORT_SYMBOL_GPL(s390_reset_acc); -- 2.25.0