From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: Janosch Frank <frankja@linux.ibm.com>
Cc: kvm@vger.kernel.org, cohuck@redhat.com, borntraeger@de.ibm.com,
thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
Ulrich.Weigand@de.ibm.com
Subject: Re: [PATCH v5 08/14] KVM: s390: pv: handle secure storage exceptions for normal guests
Date: Tue, 12 Oct 2021 10:35:50 +0200 [thread overview]
Message-ID: <20211012103550.501857f5@p-imbrenda> (raw)
In-Reply-To: <f442a49f-dbc4-5c38-ffa1-6b17742592c3@linux.ibm.com>
On Tue, 12 Oct 2021 10:16:26 +0200
Janosch Frank <frankja@linux.ibm.com> wrote:
> On 9/20/21 15:24, Claudio Imbrenda wrote:
> > With upcoming patches, normal guests might touch secure pages.
> >
> > This patch extends the existing exception handler to convert the pages
> > to non secure also when the exception is triggered by a normal guest.
> >
> > This can happen for example when a secure guest reboots; the first
> > stage of a secure guest is non secure, and in general a secure guest
> > can reboot into non-secure mode.
> >
> > If the secure memory of the previous boot has not been cleared up
> > completely yet, a non-secure guest might touch secure memory, which
> > will need to be handled properly.
> >
> > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> > ---
> > arch/s390/mm/fault.c | 10 +++++++++-
> > 1 file changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
> > index eb68b4f36927..74784581f42d 100644
> > --- a/arch/s390/mm/fault.c
> > +++ b/arch/s390/mm/fault.c
> > @@ -767,6 +767,7 @@ void do_secure_storage_access(struct pt_regs *regs)
> > struct vm_area_struct *vma;
> > struct mm_struct *mm;
> > struct page *page;
> > + struct gmap *gmap;
> > int rc;
> >
> > /*
> > @@ -796,6 +797,14 @@ void do_secure_storage_access(struct pt_regs *regs)
> > }
> >
> > switch (get_fault_type(regs)) {
> > + case GMAP_FAULT:
> > + gmap = (struct gmap *)S390_lowcore.gmap;
> > + addr = __gmap_translate(gmap, addr);
> > + if (IS_ERR_VALUE(addr)) {
> > + do_fault_error(regs, VM_ACCESS_FLAGS, VM_FAULT_BADMAP);
> > + break;
> > + }
> > + fallthrough;
>
> This would trigger an export and not a destroy, right?
correct. but this would only happen for leftover secure pages touched
by non-secure guests, before the background thread could clean them up.
>
> > case USER_FAULT:
> > mm = current->mm;
> > mmap_read_lock(mm);
> > @@ -824,7 +833,6 @@ void do_secure_storage_access(struct pt_regs *regs)
> > if (rc)
> > BUG();
> > break;
> > - case GMAP_FAULT:
> > default:
> > do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
> > WARN_ON_ONCE(1);
> >
>
next prev parent reply other threads:[~2021-10-12 8:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-20 13:24 [PATCH v5 00/14] KVM: s390: pv: implement lazy destroy for reboot Claudio Imbrenda
2021-09-20 13:24 ` [PATCH v5 01/14] KVM: s390: pv: add macros for UVC CC values Claudio Imbrenda
2021-10-05 13:08 ` Janosch Frank
2021-09-20 13:24 ` [PATCH v5 02/14] KVM: s390: pv: avoid double free of sida page Claudio Imbrenda
2021-10-05 13:11 ` Janosch Frank
2021-10-05 13:38 ` Christian Borntraeger
2021-09-20 13:24 ` [PATCH v5 03/14] KVM: s390: pv: avoid stalls for kvm_s390_pv_init_vm Claudio Imbrenda
2021-10-05 13:20 ` Janosch Frank
2021-09-20 13:24 ` [PATCH v5 04/14] KVM: s390: pv: avoid stalls when making pages secure Claudio Imbrenda
2021-10-06 15:54 ` Christian Borntraeger
2021-10-06 16:14 ` Claudio Imbrenda
2021-10-12 7:43 ` Janosch Frank
2021-10-12 8:59 ` Christian Borntraeger
2021-09-20 13:24 ` [PATCH v5 05/14] KVM: s390: pv: leak the topmost page table when destroy fails Claudio Imbrenda
2021-10-12 7:58 ` Janosch Frank
2021-10-12 8:33 ` Claudio Imbrenda
2021-09-20 13:24 ` [PATCH v5 06/14] KVM: s390: pv: properly handle page flags for protected guests Claudio Imbrenda
2021-10-12 7:59 ` Janosch Frank
2021-10-26 11:53 ` Christian Borntraeger
2021-09-20 13:24 ` [PATCH v5 07/14] KVM: s390: pv: handle secure storage violations " Claudio Imbrenda
2021-09-20 13:24 ` [PATCH v5 08/14] KVM: s390: pv: handle secure storage exceptions for normal guests Claudio Imbrenda
2021-10-12 8:16 ` Janosch Frank
2021-10-12 8:35 ` Claudio Imbrenda [this message]
2021-10-12 12:31 ` Janosch Frank
2021-09-20 13:24 ` [PATCH v5 09/14] KVM: s390: pv: refactor s390_reset_acc Claudio Imbrenda
2021-09-20 13:24 ` [PATCH v5 10/14] KVM: s390: pv: usage counter instead of flag Claudio Imbrenda
2021-09-20 13:24 ` [PATCH v5 11/14] KVM: s390: pv: add export before import Claudio Imbrenda
2021-09-20 13:25 ` [PATCH v5 12/14] KVM: s390: pv: module parameter to fence lazy destroy Claudio Imbrenda
2021-09-20 13:25 ` [PATCH v5 13/14] KVM: s390: pv: lazy destroy for reboot Claudio Imbrenda
2021-09-20 13:25 ` [PATCH v5 14/14] KVM: s390: pv: avoid export before import if possible Claudio Imbrenda
2021-10-05 13:26 ` [PATCH v5 00/14] KVM: s390: pv: implement lazy destroy for reboot Janosch Frank
2021-10-05 14:15 ` Christian Borntraeger
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211012103550.501857f5@p-imbrenda \
--to=imbrenda@linux.ibm.com \
--cc=Ulrich.Weigand@de.ibm.com \
--cc=borntraeger@de.ibm.com \
--cc=cohuck@redhat.com \
--cc=david@redhat.com \
--cc=frankja@linux.ibm.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=pasic@linux.ibm.com \
--cc=thuth@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).