From 005ba37cb89bcc0cf63c2029a41f8db165aeb615 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 8 Jan 2020 12:24:36 -0800 Subject: mm: thp: KVM: Explicitly check for THP when populating secondary MMU Add a helper, is_transparent_hugepage(), to explicitly check whether a compound page is a THP and use it when populating KVM's secondary MMU. The explicit check fixes a bug where a remapped compound page, e.g. for an XDP Rx socket, is mapped into a KVM guest and is mistaken for a THP, which results in KVM incorrectly creating a huge page in its secondary MMU. Fixes: 936a5fe6e6148 ("thp: kvm mmu transparent hugepage support") Reported-by: syzbot+c9d1fb51ac9d0d10c39d@syzkaller.appspotmail.com Cc: Andrea Arcangeli Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- virt/kvm/arm/mmu.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'virt/kvm/arm') diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 0b32a904a1bb..dc8254bf30ea 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1377,14 +1377,8 @@ static bool transparent_hugepage_adjust(kvm_pfn_t *pfnp, phys_addr_t *ipap) { kvm_pfn_t pfn = *pfnp; gfn_t gfn = *ipap >> PAGE_SHIFT; - struct page *page = pfn_to_page(pfn); - /* - * PageTransCompoundMap() returns true for THP and - * hugetlbfs. Make sure the adjustment is done only for THP - * pages. - */ - if (!PageHuge(page) && PageTransCompoundMap(page)) { + if (kvm_is_transparent_hugepage(pfn)) { unsigned long mask; /* * The address we faulted on is backed by a transparent huge -- cgit v1.2.3-70-g09d2