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| author | Wanpeng Li <wanpeng.li@linux.intel.com> | 2015-04-15 10:24:54 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-04-15 17:01:01 +0200 |
| commit | 130005231c9f2090b1b177e2cca9841b562c1784 (patch) | |
| tree | 3a08b71fe1577f3848af20f47381ae661d664243 /arch/x86 | |
| parent | 95fce4fa0850da8f85ecf8d069ab3fc6c8bc1478 (diff) | |
| download | linux-130005231c9f2090b1b177e2cca9841b562c1784.tar.gz linux-130005231c9f2090b1b177e2cca9841b562c1784.tar.bz2 linux-130005231c9f2090b1b177e2cca9841b562c1784.zip | |
kvm: mmu: don't do memslot overflow check
As Andres pointed out:
| I don't understand the value of this check here. Are we looking for a
| broken memslot? Shouldn't this be a BUG_ON? Is this the place to care
| about these things? npages is capped to KVM_MEM_MAX_NR_PAGES, i.e.
| 2^31. A 64 bit overflow would be caused by a gigantic gfn_start which
| would be trouble in many other ways.
This patch drops the memslot overflow check to make the codes more simple.
Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com>
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Message-Id: <1429064694-3072-1-git-send-email-wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 12 |
1 files changed, 2 insertions, 10 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 146f295ee322..07bb22157338 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4504,19 +4504,12 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm, bool flush = false; unsigned long *rmapp; unsigned long last_index, index; - gfn_t gfn_start, gfn_end; spin_lock(&kvm->mmu_lock); - gfn_start = memslot->base_gfn; - gfn_end = memslot->base_gfn + memslot->npages - 1; - - if (gfn_start >= gfn_end) - goto out; - rmapp = memslot->arch.rmap[0]; - last_index = gfn_to_index(gfn_end, memslot->base_gfn, - PT_PAGE_TABLE_LEVEL); + last_index = gfn_to_index(memslot->base_gfn + memslot->npages - 1, + memslot->base_gfn, PT_PAGE_TABLE_LEVEL); for (index = 0; index <= last_index; ++index, ++rmapp) { if (*rmapp) @@ -4534,7 +4527,6 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm, if (flush) kvm_flush_remote_tlbs(kvm); -out: spin_unlock(&kvm->mmu_lock); } |