diff options
| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-01-08 12:24:36 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-01-27 20:00:01 +0100 |
| commit | 005ba37cb89bcc0cf63c2029a41f8db165aeb615 (patch) | |
| tree | 0d0b3d133dfd012cfe53f548397308a7089da89c /virt | |
| parent | 22b1d57b032cea4d612746473ed28cb20665d876 (diff) | |
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')
| -rw-r--r-- | virt/kvm/arm/mmu.c | 8 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 10 |
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() */ |