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Shutemov" X-Google-Original-From: "Kirill A. Shutemov" Received: by box.localdomain (Postfix, from userid 1000) id 344C2102F6E; Tue, 20 Oct 2020 09:19:02 +0300 (+03) To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel Cc: David Rientjes , Andrea Arcangeli , Kees Cook , Will Drewry , "Edgecombe, Rick P" , "Kleen, Andi" , Liran Alon , Mike Rapoport , x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [RFCv2 15/16] KVM: Unmap protected pages from direct mapping Date: Tue, 20 Oct 2020 09:18:58 +0300 Message-Id: <20201020061859.18385-16-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201020061859.18385-1-kirill.shutemov@linux.intel.com> References: <20201020061859.18385-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: If the protected memory feature enabled, unmap guest memory from kernel's direct mappings. Migration and KSM is disabled for protected memory as it would require a special treatment. Signed-off-by: Kirill A. Shutemov --- include/linux/mm.h | 3 +++ mm/huge_memory.c | 8 ++++++++ mm/ksm.c | 2 ++ mm/memory.c | 12 ++++++++++++ mm/rmap.c | 4 ++++ virt/lib/mem_protected.c | 21 +++++++++++++++++++++ 6 files changed, 50 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index ee274d27e764..74efc51e63f0 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -671,6 +671,9 @@ static inline bool vma_is_kvm_protected(struct vm_are= a_struct *vma) return vma->vm_flags & VM_KVM_PROTECTED; } =20 +void kvm_map_page(struct page *page, int nr_pages); +void kvm_unmap_page(struct page *page, int nr_pages); + #ifdef CONFIG_SHMEM /* * The vma_is_shmem is not inline because it is used only by slow diff --git a/mm/huge_memory.c b/mm/huge_memory.c index ec8cf9a40cfd..40974656cb43 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -627,6 +627,10 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struc= t vm_fault *vmf, spin_unlock(vmf->ptl); count_vm_event(THP_FAULT_ALLOC); count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); + + /* Unmap page from direct mapping */ + if (vma_is_kvm_protected(vma)) + kvm_unmap_page(page, HPAGE_PMD_NR); } =20 return 0; @@ -1689,6 +1693,10 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm= _area_struct *vma, page_remove_rmap(page, true); VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); VM_BUG_ON_PAGE(!PageHead(page), page); + + /* Map the page back to the direct mapping */ + if (vma_is_kvm_protected(vma)) + kvm_map_page(page, HPAGE_PMD_NR); } else if (thp_migration_supported()) { swp_entry_t entry; =20 diff --git a/mm/ksm.c b/mm/ksm.c index 9afccc36dbd2..c720e271448f 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -528,6 +528,8 @@ static struct vm_area_struct *find_mergeable_vma(stru= ct mm_struct *mm, return NULL; if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma) return NULL; + if (vma_is_kvm_protected(vma)) + return NULL; return vma; } =20 diff --git a/mm/memory.c b/mm/memory.c index 2c9756b4e52f..e28bd5f902a7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1245,6 +1245,11 @@ static unsigned long zap_pte_range(struct mmu_gath= er *tlb, likely(!(vma->vm_flags & VM_SEQ_READ))) mark_page_accessed(page); } + + /* Map the page back to the direct mapping */ + if (vma_is_anonymous(vma) && vma_is_kvm_protected(vma)) + kvm_map_page(page, 1); + rss[mm_counter(page)]--; page_remove_rmap(page, false); if (unlikely(page_mapcount(page) < 0)) @@ -3466,6 +3471,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault= *vmf) struct page *page; vm_fault_t ret =3D 0; pte_t entry; + bool set =3D false; =20 /* File mapping without ->vm_ops ? */ if (vma->vm_flags & VM_SHARED) @@ -3554,6 +3560,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault= *vmf) inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); page_add_new_anon_rmap(page, vma, vmf->address, false); lru_cache_add_inactive_or_unevictable(page, vma); + set =3D true; setpte: set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); =20 @@ -3561,6 +3568,11 @@ static vm_fault_t do_anonymous_page(struct vm_faul= t *vmf) update_mmu_cache(vma, vmf->address, vmf->pte); unlock: pte_unmap_unlock(vmf->pte, vmf->ptl); + + /* Unmap page from direct mapping */ + if (vma_is_kvm_protected(vma) && set) + kvm_unmap_page(page, 1); + return ret; release: put_page(page); diff --git a/mm/rmap.c b/mm/rmap.c index 9425260774a1..247548d6d24b 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1725,6 +1725,10 @@ static bool try_to_unmap_one(struct page *page, st= ruct vm_area_struct *vma, =20 static bool invalid_migration_vma(struct vm_area_struct *vma, void *arg) { + /* TODO */ + if (vma_is_kvm_protected(vma)) + return true; + return vma_is_temporary_stack(vma); } =20 diff --git a/virt/lib/mem_protected.c b/virt/lib/mem_protected.c index 1dfe82534242..9d2ef99285e5 100644 --- a/virt/lib/mem_protected.c +++ b/virt/lib/mem_protected.c @@ -30,6 +30,27 @@ void kvm_unmap_page_atomic(void *vaddr) } EXPORT_SYMBOL_GPL(kvm_unmap_page_atomic); =20 +void kvm_map_page(struct page *page, int nr_pages) +{ + int i; + + /* Clear page before returning it to the direct mapping */ + for (i =3D 0; i < nr_pages; i++) { + void *p =3D kvm_map_page_atomic(page + i); + memset(p, 0, PAGE_SIZE); + kvm_unmap_page_atomic(p); + } + + kernel_map_pages(page, nr_pages, 1); +} +EXPORT_SYMBOL_GPL(kvm_map_page); + +void kvm_unmap_page(struct page *page, int nr_pages) +{ + kernel_map_pages(page, nr_pages, 0); +} +EXPORT_SYMBOL_GPL(kvm_unmap_page); + int kvm_init_protected_memory(void) { guest_map_ptes =3D kmalloc_array(num_possible_cpus(), --=20 2.26.2