+++ /dev/null
-From f153850a9af201873191546dd40bc36088c06b66 Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Fri, 28 Apr 2023 11:27:53 +0200
-Subject: KVM: s390: fix race in gmap_make_secure()
-
-From: Claudio Imbrenda <imbrenda@linux.ibm.com>
-
-[ Upstream commit c148dc8e2fa403be501612ee409db866eeed35c0 ]
-
-Fix a potential race in gmap_make_secure() and remove the last user of
-follow_page() without FOLL_GET.
-
-The old code is locking something it doesn't have a reference to, and
-as explained by Jason and David in this discussion:
-https://lore.kernel.org/linux-mm/Y9J4P%2FRNvY1Ztn0Q@nvidia.com/
-it can lead to all kind of bad things, including the page getting
-unmapped (MADV_DONTNEED), freed, reallocated as a larger folio and the
-unlock_page() would target the wrong bit.
-There is also another race with the FOLL_WRITE, which could race
-between the follow_page() and the get_locked_pte().
-
-The main point is to remove the last use of follow_page() without
-FOLL_GET or FOLL_PIN, removing the races can be considered a nice
-bonus.
-
-Link: https://lore.kernel.org/linux-mm/Y9J4P%2FRNvY1Ztn0Q@nvidia.com/
-Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
-Fixes: 214d9bbcd3a6 ("s390/mm: provide memory management functions for protected KVM guests")
-Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
-Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
-Message-Id: <20230428092753.27913-2-imbrenda@linux.ibm.com>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- arch/s390/kernel/uv.c | 32 +++++++++++---------------------
- 1 file changed, 11 insertions(+), 21 deletions(-)
-
-diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
-index 7d7961c7b1281..66d1248c8c923 100644
---- a/arch/s390/kernel/uv.c
-+++ b/arch/s390/kernel/uv.c
-@@ -160,21 +160,10 @@ static int expected_page_refs(struct page *page)
- return res;
- }
-
--static int make_secure_pte(pte_t *ptep, unsigned long addr,
-- struct page *exp_page, struct uv_cb_header *uvcb)
-+static int make_page_secure(struct page *page, struct uv_cb_header *uvcb)
- {
-- pte_t entry = READ_ONCE(*ptep);
-- struct page *page;
- int expected, rc = 0;
-
-- if (!pte_present(entry))
-- return -ENXIO;
-- if (pte_val(entry) & _PAGE_INVALID)
-- return -ENXIO;
--
-- page = pte_page(entry);
-- if (page != exp_page)
-- return -ENXIO;
- if (PageWriteback(page))
- return -EAGAIN;
- expected = expected_page_refs(page);
-@@ -252,17 +241,18 @@ int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb)
- goto out;
-
- rc = -ENXIO;
-- page = follow_page(vma, uaddr, FOLL_WRITE);
-- if (IS_ERR_OR_NULL(page))
-- goto out;
--
-- 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);
-+ if (pte_present(*ptep) && !(pte_val(*ptep) & _PAGE_INVALID) && pte_write(*ptep)) {
-+ page = pte_page(*ptep);
-+ rc = -EAGAIN;
-+ if (trylock_page(page)) {
-+ if (should_export_before_import(uvcb, gmap->mm))
-+ uv_convert_from_secure(page_to_phys(page));
-+ rc = make_page_secure(page, uvcb);
-+ unlock_page(page);
-+ }
-+ }
- pte_unmap_unlock(ptep, ptelock);
-- unlock_page(page);
- out:
- mmap_read_unlock(gmap->mm);
-
---
-2.39.2
-
+++ /dev/null
-From 3c20c539670f2e36a9a52b8db8aef56467e20f4b Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Tue, 28 Jun 2022 15:56:07 +0200
-Subject: KVM: s390: pv: add export before import
-
-From: Claudio Imbrenda <imbrenda@linux.ibm.com>
-
-[ Upstream commit 72b1daff2671cef2c8cccc6c4e52f8d5ce4ebe58 ]
-
-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>
-Link: https://lore.kernel.org/r/20220628135619.32410-7-imbrenda@linux.ibm.com
-Message-Id: <20220628135619.32410-7-imbrenda@linux.ibm.com>
-Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
-Stable-dep-of: c148dc8e2fa4 ("KVM: s390: fix race in gmap_make_secure()")
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- arch/s390/kernel/uv.c | 28 ++++++++++++++++++++++++++++
- 1 file changed, 28 insertions(+)
-
-diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
-index f95ccbd396925..7d7961c7b1281 100644
---- a/arch/s390/kernel/uv.c
-+++ b/arch/s390/kernel/uv.c
-@@ -189,6 +189,32 @@ static int make_secure_pte(pte_t *ptep, unsigned long addr,
- return rc;
- }
-
-+/**
-+ * should_export_before_import - Determine whether an export is needed
-+ * before an import-like operation
-+ * @uvcb: the Ultravisor control block of the UVC to be performed
-+ * @mm: the mm of the process
-+ *
-+ * Returns whether an export is needed before every import-like operation.
-+ * This is needed for shared pages, which don't trigger a secure storage
-+ * exception when accessed from a different guest.
-+ *
-+ * Although considered as one, the Unpin Page UVC is not an actual import,
-+ * so it is not affected.
-+ *
-+ * No export is needed also when there is only one protected VM, because the
-+ * page cannot belong to the wrong VM in that case (there is no "other VM"
-+ * it can belong to).
-+ *
-+ * Return: true if an export is needed before every import, otherwise false.
-+ */
-+static bool should_export_before_import(struct uv_cb_header *uvcb, struct mm_struct *mm)
-+{
-+ if (uvcb->cmd == UVC_CMD_UNPIN_PAGE_SHARED)
-+ return false;
-+ return atomic_read(&mm->context.protected_count) > 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
-@@ -232,6 +258,8 @@ 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);
---
-2.39.2
-
platform-x86-isst-punit-device-mapping-with-sub-numa.patch
platform-x86-isst-remove-8-socket-limit.patch
net-phy-mscc-enable-vsc8501-2-rgmii-rx-clock.patch
-kvm-s390-pv-add-export-before-import.patch
-kvm-s390-fix-race-in-gmap_make_secure.patch
net-dsa-introduce-helpers-for-iterating-through-port.patch
net-dsa-mt7530-rework-mt753-01-_setup.patch
net-dsa-mt7530-split-off-common-parts-from-mt7531_se.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
