From: David Hildenbrand <david@redhat.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>,
Janosch Frank <frankja@linux.vnet.ibm.com>
Cc: KVM <kvm@vger.kernel.org>, Cornelia Huck <cohuck@redhat.com>,
Thomas Huth <thuth@redhat.com>,
Ulrich Weigand <Ulrich.Weigand@de.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-s390 <linux-s390@vger.kernel.org>,
Michael Mueller <mimu@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 11/35] KVM: s390/mm: Make pages accessible before destroying the guest
Date: Fri, 14 Feb 2020 19:40:56 +0100 [thread overview]
Message-ID: <d44194a4-c9f0-7114-c633-327ebb553517@redhat.com> (raw)
In-Reply-To: <20200207113958.7320-12-borntraeger@de.ibm.com>
On 07.02.20 12:39, Christian Borntraeger wrote:
> 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 <borntraeger@de.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> ---
> arch/s390/include/asm/pgtable.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/pgtable.h b/arch/s390/include/asm/pgtable.h
> index dbd1453e6924..3e2ea997c334 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -1669,6 +1669,7 @@ extern int vmem_remove_mapping(unsigned long start, unsigned long size);
> extern int s390_enable_sie(void);
> extern int s390_enable_skey(void);
> extern void s390_reset_cmma(struct mm_struct *mm);
> +extern void s390_reset_acc(struct mm_struct *mm);
>
> /* s390 has a private copy of get unmapped area to deal with cache synonyms */
> #define HAVE_ARCH_UNMAPPED_AREA
> diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
> index 4795e61f4e16..392795a92bd9 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)
> int rc;
> u32 ret;
>
> + /* make all pages accessible before destroying the guest */
> + s390_reset_acc(kvm->mm);
> rc = uv_cmd_nodata(kvm_s390_pv_handle(kvm),
> UVC_CMD_DESTROY_SEC_CONF, &ret);
> 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 <linux/sched/mm.h>
> +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);
>
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-02-14 18:41 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 11:39 [PATCH 00/35] KVM: s390: Add support for protected VMs Christian Borntraeger
2020-02-07 11:39 ` [PATCH 01/35] mm:gup/writeback: add callbacks for inaccessible pages Christian Borntraeger
2020-02-10 17:27 ` Christian Borntraeger
2020-02-11 11:26 ` Will Deacon
2020-02-11 11:43 ` Christian Borntraeger
2020-02-13 14:48 ` Christian Borntraeger
2020-02-18 16:02 ` Will Deacon
2020-02-13 19:56 ` Sean Christopherson
2020-02-13 20:13 ` Christian Borntraeger
2020-02-13 20:46 ` Sean Christopherson
2020-02-17 20:55 ` Tom Lendacky
2020-02-17 21:14 ` Christian Borntraeger
2020-02-10 18:17 ` David Hildenbrand
2020-02-10 18:28 ` Christian Borntraeger
2020-02-10 18:43 ` David Hildenbrand
2020-02-10 18:51 ` Christian Borntraeger
2020-02-18 3:36 ` Tian, Kevin
2020-02-18 6:44 ` Christian Borntraeger
2020-02-07 11:39 ` [PATCH 02/35] KVM: s390/interrupt: do not pin adapter interrupt pages Christian Borntraeger
2020-02-10 12:26 ` David Hildenbrand
2020-02-10 18:38 ` Christian Borntraeger
2020-02-10 19:33 ` David Hildenbrand
2020-02-11 9:23 ` [PATCH v2 RFC] " Christian Borntraeger
2020-02-12 11:52 ` Christian Borntraeger
2020-02-12 12:16 ` David Hildenbrand
2020-02-12 12:22 ` Christian Borntraeger
2020-02-12 12:47 ` David Hildenbrand
2020-02-12 12:39 ` Cornelia Huck
2020-02-12 12:44 ` Christian Borntraeger
2020-02-12 13:07 ` Cornelia Huck
2020-02-10 18:56 ` [PATCH 02/35] KVM: s390/interrupt: do not pin adapter interrupt Ulrich Weigand
2020-02-10 12:40 ` [PATCH 02/35] KVM: s390/interrupt: do not pin adapter interrupt pages David Hildenbrand
2020-02-07 11:39 ` [PATCH 05/35] s390/mm: provide memory management functions for protected KVM guests Christian Borntraeger
2020-02-12 13:42 ` Cornelia Huck
2020-02-13 7:43 ` Christian Borntraeger
2020-02-13 8:44 ` Cornelia Huck
2020-02-14 17:59 ` David Hildenbrand
2020-02-14 21:17 ` Christian Borntraeger
2020-02-07 11:39 ` [PATCH 06/35] s390/mm: add (non)secure page access exceptions handlers Christian Borntraeger
2020-02-14 18:05 ` David Hildenbrand
2020-02-14 19:59 ` Christian Borntraeger
2020-02-07 11:39 ` [PATCH 10/35] KVM: s390: protvirt: Secure memory is not mergeable Christian Borntraeger
2020-02-07 11:39 ` [PATCH 11/35] KVM: s390/mm: Make pages accessible before destroying the guest Christian Borntraeger
2020-02-14 18:40 ` David Hildenbrand [this message]
2020-02-07 11:39 ` [PATCH 21/35] KVM: s390/mm: handle guest unpin events Christian Borntraeger
2020-02-10 14:58 ` Thomas Huth
2020-02-11 13:21 ` Cornelia Huck
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