From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Sean Christopherson <seanjc@google.com>,
Jim Mattson <jmattson@google.com>
Cc: David Rientjes <rientjes@google.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"Kleen, Andi" <andi.kleen@intel.com>,
"Yamahata, Isaku" <isaku.yamahata@intel.com>,
Erdem Aktas <erdemaktas@google.com>,
Steve Rutherford <srutherford@google.com>,
Peter Gonda <pgonda@google.com>,
David Hildenbrand <david@redhat.com>,
x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [RFCv2 10/13] mm: Keep page reference for hwpoison entries
Date: Fri, 16 Apr 2021 18:41:03 +0300 [thread overview]
Message-ID: <20210416154106.23721-11-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20210416154106.23721-1-kirill.shutemov@linux.intel.com>
On migration we drop referece to a page once PTE gets replaced with a
migration entry. Migration code keeps the last reference on the page
that gets dropped once migration is complete.
We do the same for hwpoison entries, but it doesn't work: nobody keeps
the reference once page is remapped with hwpoison entries.
Keep page referenced on setting up hwpoison entries, copy the reference
on fork() and return on zap().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
mm/memory.c | 6 ++++++
mm/rmap.c | 2 +-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/mm/memory.c b/mm/memory.c
index feff48e1465a..b15b0c582186 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -767,6 +767,9 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pte = pte_swp_mkuffd_wp(pte);
set_pte_at(src_mm, addr, src_pte, pte);
}
+ } else if (is_hwpoison_entry(entry)) {
+ page = hwpoison_entry_to_page(entry);
+ get_page(page);
}
set_pte_at(dst_mm, addr, dst_pte, pte);
return 0;
@@ -1305,6 +1308,9 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
page = migration_entry_to_page(entry);
rss[mm_counter(page)]--;
+
+ } else if (is_hwpoison_entry(entry)) {
+ put_page(hwpoison_entry_to_page(entry));
}
if (unlikely(!free_swap_and_cache(entry)))
print_bad_pte(vma, addr, ptent, NULL);
diff --git a/mm/rmap.c b/mm/rmap.c
index 08c56aaf72eb..f08d1fc28522 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1575,7 +1575,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
dec_mm_counter(mm, mm_counter(page));
set_pte_at(mm, address, pvmw.pte, pteval);
}
-
+ get_page(page);
} else if (pte_unused(pteval) && !userfaultfd_armed(vma)) {
/*
* The guest indicated that the page content is of no
--
2.26.3
next prev parent reply other threads:[~2021-04-16 15:41 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 15:40 [RFCv2 00/13] TDX and guest memory unmapping Kirill A. Shutemov
2021-04-16 15:40 ` [RFCv2 01/13] x86/mm: Move force_dma_unencrypted() to common code Kirill A. Shutemov
2021-04-16 15:40 ` [RFCv2 02/13] x86/kvm: Introduce KVM memory protection feature Kirill A. Shutemov
2021-04-16 16:10 ` Borislav Petkov
2021-04-19 10:10 ` Kirill A. Shutemov
2021-04-16 15:40 ` [RFCv2 03/13] x86/kvm: Make DMA pages shared Kirill A. Shutemov
2021-04-16 15:40 ` [RFCv2 04/13] x86/kvm: Use bounce buffers for KVM memory protection Kirill A. Shutemov
2021-04-16 16:21 ` Dave Hansen
2021-04-16 15:40 ` [RFCv2 05/13] x86/kvmclock: Share hvclock memory with the host Kirill A. Shutemov
2021-04-16 15:40 ` [RFCv2 06/13] x86/realmode: Share trampoline area if KVM memory protection enabled Kirill A. Shutemov
2021-04-19 16:49 ` Dave Hansen
2021-04-16 15:41 ` [RFCv2 07/13] mm: Add hwpoison_entry_to_pfn() and hwpoison_entry_to_page() Kirill A. Shutemov
2021-04-16 15:41 ` [RFCv2 08/13] mm/gup: Add FOLL_ALLOW_POISONED Kirill A. Shutemov
2021-04-16 15:41 ` [RFCv2 09/13] shmem: Fail shmem_getpage_gfp() on poisoned pages Kirill A. Shutemov
2021-04-16 15:41 ` Kirill A. Shutemov [this message]
2021-04-16 15:41 ` [RFCv2 11/13] mm: Replace hwpoison entry with present PTE if page got unpoisoned Kirill A. Shutemov
2021-04-16 15:41 ` [RFCv2 12/13] KVM: passdown struct kvm to hva_to_pfn_slow() Kirill A. Shutemov
2021-04-16 15:41 ` [RFCv2 13/13] KVM: unmap guest memory using poisoned pages Kirill A. Shutemov
2021-04-16 17:30 ` Sean Christopherson
2021-04-19 11:32 ` Xiaoyao Li
2021-04-19 14:26 ` Kirill A. Shutemov
2021-04-19 16:01 ` Sean Christopherson
2021-04-19 16:40 ` Kirill A. Shutemov
2021-04-19 18:09 ` Sean Christopherson
2021-04-19 18:12 ` David Hildenbrand
2021-04-19 18:53 ` Kirill A. Shutemov
2021-04-19 20:09 ` Sean Christopherson
2021-04-19 22:57 ` Kirill A. Shutemov
2021-04-20 17:13 ` Sean Christopherson
2021-05-21 12:31 ` Kirill A. Shutemov
2021-05-26 19:46 ` Sean Christopherson
2021-05-31 20:07 ` Kirill A. Shutemov
2021-06-02 17:51 ` Sean Christopherson
2021-06-02 23:33 ` Kirill A. Shutemov
2021-06-03 19:46 ` Sean Christopherson
2021-06-04 14:29 ` Kirill A. Shutemov
2021-06-04 17:16 ` Andy Lutomirski
2021-06-04 17:54 ` Kirill A. Shutemov
2021-04-16 16:46 ` [RFCv2 00/13] TDX and guest memory unmapping Matthew Wilcox
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