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From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: kvm@vger.kernel.org
Cc: cohuck@redhat.com, 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,
	Ulrich.Weigand@de.ibm.com
Subject: [PATCH v4 11/14] KVM: s390: pv: add export before import
Date: Wed, 18 Aug 2021 15:26:17 +0200	[thread overview]
Message-ID: <20210818132620.46770-12-imbrenda@linux.ibm.com> (raw)
In-Reply-To: <20210818132620.46770-1-imbrenda@linux.ibm.com>

Due to upcoming changes, it will be possible to temporarily have
multiple protected VMs in the same address space, although only one
will be actually active.

In that scenario, it is necessary to perform an export of every page
that is to be imported, since the hardware does not allow a page
belonging to a protected guest to be imported into a different
protected guest.

This also applies to pages that are shared, and thus accessible by the
host.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
---
 arch/s390/kernel/uv.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index 89ba36a5b4bb..bc79085d7152 100644
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -249,6 +249,12 @@ static int make_secure_pte(pte_t *ptep, unsigned long addr,
 	return uvcb->rc == 0x10a ? -ENXIO : -EINVAL;
 }
 
+static bool should_export_before_import(struct uv_cb_header *uvcb, struct mm_struct *mm)
+{
+	return uvcb->cmd != UVC_CMD_UNPIN_PAGE_SHARED &&
+		atomic_read(&mm->context.is_protected) > 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
@@ -292,6 +298,8 @@ int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb)
 
 	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);
-- 
2.31.1


  parent reply	other threads:[~2021-08-18 13:27 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-18 13:26 [PATCH v4 00/14] KVM: s390: pv: implement lazy destroy for reboot Claudio Imbrenda
2021-08-18 13:26 ` [PATCH v4 01/14] KVM: s390: pv: add macros for UVC CC values Claudio Imbrenda
2021-08-31 13:43   ` Christian Borntraeger
2021-08-18 13:26 ` [PATCH v4 02/14] KVM: s390: pv: avoid double free of sida page Claudio Imbrenda
2021-08-31 13:55   ` Christian Borntraeger
2021-09-08 18:50     ` Claudio Imbrenda
2021-08-31 13:59   ` Janosch Frank
2021-08-18 13:26 ` [PATCH v4 03/14] KVM: s390: pv: avoid stalls for kvm_s390_pv_init_vm Claudio Imbrenda
2021-08-31 14:10   ` Christian Borntraeger
2021-08-18 13:26 ` [PATCH v4 04/14] KVM: s390: pv: avoid stalls when making pages secure Claudio Imbrenda
2021-08-31 14:32   ` Christian Borntraeger
2021-08-31 15:00     ` Claudio Imbrenda
2021-08-31 15:11       ` Christian Borntraeger
2021-08-18 13:26 ` [PATCH v4 05/14] KVM: s390: pv: leak the ASCE page when destroy fails Claudio Imbrenda
2021-09-06 15:32   ` Christian Borntraeger
2021-09-06 15:54     ` Claudio Imbrenda
2021-08-18 13:26 ` [PATCH v4 06/14] KVM: s390: pv: properly handle page flags for protected guests Claudio Imbrenda
2021-09-06 15:46   ` Christian Borntraeger
2021-09-06 15:56     ` Claudio Imbrenda
2021-09-06 16:16       ` Christian Borntraeger
2021-09-17 14:57         ` Claudio Imbrenda
2021-08-18 13:26 ` [PATCH v4 07/14] KVM: s390: pv: handle secure storage violations " Claudio Imbrenda
2021-08-18 13:26 ` [PATCH v4 08/14] KVM: s390: pv: handle secure storage exceptions for normal guests Claudio Imbrenda
2021-08-18 13:26 ` [PATCH v4 09/14] KVM: s390: pv: refactor s390_reset_acc Claudio Imbrenda
2021-08-18 13:26 ` [PATCH v4 10/14] KVM: s390: pv: usage counter instead of flag Claudio Imbrenda
2021-08-26  7:58   ` Janis Schoetterl-Glausch
2021-08-18 13:26 ` Claudio Imbrenda [this message]
2021-08-18 13:26 ` [PATCH v4 12/14] KVM: s390: pv: module parameter to fence lazy destroy Claudio Imbrenda
2021-08-18 13:26 ` [PATCH v4 13/14] KVM: s390: pv: lazy destroy for reboot Claudio Imbrenda
2021-08-26  8:33   ` Janis Schoetterl-Glausch
2021-08-18 13:26 ` [PATCH v4 14/14] KVM: s390: pv: avoid export before import if possible Claudio Imbrenda

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