lkml.org 
[lkml]   [2018]   [Nov]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 255/361] KVM: arm/arm64: Ensure only THP is candidate for adjustment
    Date
    4.19-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Punit Agrawal <punit.agrawal@arm.com>

    commit fd2ef358282c849c193aa36dadbf4f07f7dcd29b upstream.

    PageTransCompoundMap() returns true for hugetlbfs and THP
    hugepages. This behaviour incorrectly leads to stage 2 faults for
    unsupported hugepage sizes (e.g., 64K hugepage with 4K pages) to be
    treated as THP faults.

    Tighten the check to filter out hugetlbfs pages. This also leads to
    consistently mapping all unsupported hugepage sizes as PTE level
    entries at stage 2.

    Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
    Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com>
    Cc: Christoffer Dall <christoffer.dall@arm.com>
    Cc: Marc Zyngier <marc.zyngier@arm.com>
    Cc: stable@vger.kernel.org # v4.13+
    Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    virt/kvm/arm/mmu.c | 8 +++++++-
    1 file changed, 7 insertions(+), 1 deletion(-)

    --- a/virt/kvm/arm/mmu.c
    +++ b/virt/kvm/arm/mmu.c
    @@ -1230,8 +1230,14 @@ static bool transparent_hugepage_adjust(
    {
    kvm_pfn_t pfn = *pfnp;
    gfn_t gfn = *ipap >> PAGE_SHIFT;
    + struct page *page = pfn_to_page(pfn);

    - if (PageTransCompoundMap(pfn_to_page(pfn))) {
    + /*
    + * PageTransCompoungMap() returns true for THP and
    + * hugetlbfs. Make sure the adjustment is done only for THP
    + * pages.
    + */
    + if (!PageHuge(page) && PageTransCompoundMap(page)) {
    unsigned long mask;
    /*
    * The address we faulted on is backed by a transparent huge

    \
     
     \ /
      Last update: 2018-11-12 00:56    [W:4.283 / U:0.048 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site