lkml.org 
[lkml]   [2021]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    Subject[PATCH v3 1/3] KVM: x86/mmu: Remove redundant spte present check in mmu_set_spte
    From
    Drop an unnecessary is_shadow_present_pte() check when updating the rmaps
    after installing a non-MMIO SPTE. set_spte() is used only to create
    shadow-present SPTEs, e.g. MMIO SPTEs are handled early on, mmu_set_spte()
    runs with mmu_lock held for write, i.e. the SPTE can't be zapped between
    writing the SPTE and updating the rmaps.

    Opportunistically combine the "new SPTE" logic for large pages and rmaps.

    No functional change intended.

    Suggested-by: Ben Gardon <bgardon@google.com>

    Reviewed-by: Ben Gardon <bgardon@google.com>
    Reviewed-by: Sean Christopherson <seanjc@google.com>
    Signed-off-by: Mingwei Zhang <mizhang@google.com>
    ---
    arch/x86/kvm/mmu/mmu.c | 14 ++++++--------
    1 file changed, 6 insertions(+), 8 deletions(-)

    diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
    index b888385d1933..442cc554ebd6 100644
    --- a/arch/x86/kvm/mmu/mmu.c
    +++ b/arch/x86/kvm/mmu/mmu.c
    @@ -2690,15 +2690,13 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,

    pgprintk("%s: setting spte %llx\n", __func__, *sptep);
    trace_kvm_mmu_set_spte(level, gfn, sptep);
    - if (!was_rmapped && is_large_pte(*sptep))
    - ++vcpu->kvm->stat.lpages;

    - if (is_shadow_present_pte(*sptep)) {
    - if (!was_rmapped) {
    - rmap_count = rmap_add(vcpu, sptep, gfn);
    - if (rmap_count > RMAP_RECYCLE_THRESHOLD)
    - rmap_recycle(vcpu, sptep, gfn);
    - }
    + if (!was_rmapped) {
    + if (is_large_pte(*sptep))
    + ++vcpu->kvm->stat.lpages;
    + rmap_count = rmap_add(vcpu, sptep, gfn);
    + if (rmap_count > RMAP_RECYCLE_THRESHOLD)
    + rmap_recycle(vcpu, sptep, gfn);
    }

    return ret;
    --
    2.32.0.554.ge1b32706d8-goog
    \
     
     \ /
      Last update: 2021-07-31 01:01    [W:2.824 / U:0.172 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site