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authorSean Christopherson <sean.j.christopherson@intel.com>2020-01-08 12:24:36 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2020-01-27 20:00:01 +0100
commit005ba37cb89bcc0cf63c2029a41f8db165aeb615 (patch)
tree0d0b3d133dfd012cfe53f548397308a7089da89c /virt/kvm
parent22b1d57b032cea4d612746473ed28cb20665d876 (diff)
downloadlinux-005ba37cb89bcc0cf63c2029a41f8db165aeb615.tar.bz2
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 <aarcange@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt/kvm')
-rw-r--r--virt/kvm/arm/mmu.c8
-rw-r--r--virt/kvm/kvm_main.c10
2 files changed, 11 insertions, 7 deletions
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
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ffec9f427b55..64e9e9d65ed4 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -191,6 +191,16 @@ bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
return true;
}
+bool kvm_is_transparent_hugepage(kvm_pfn_t pfn)
+{
+ struct page *page = pfn_to_page(pfn);
+
+ if (!PageTransCompoundMap(page))
+ return false;
+
+ return is_transparent_hugepage(compound_head(page));
+}
+
/*
* Switches to specified vcpu, until a matching vcpu_put()
*/