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KVM: MMU: fix rmap_remove on non present sptes 

drop_spte should not attempt to rmap_remove a non present shadow pte.

This fixes a BUG_ON seen on kvm-autotest.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Reported-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
hifive-unleashed-5.1
Marcelo Tosatti 2010-10-25 11:58:22 -02:00
parent edde99ce05
commit eb45fda45f
1 changed files with 5 additions and 4 deletions
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9
arch/x86/kvm/mmu.c
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@ -720,7 +720,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
}
}
static void set_spte_track_bits(u64 *sptep, u64 new_spte)
static int set_spte_track_bits(u64 *sptep, u64 new_spte)
{
pfn_t pfn;
u64 old_spte = *sptep;
@ -731,19 +731,20 @@ static void set_spte_track_bits(u64 *sptep, u64 new_spte)
old_spte = __xchg_spte(sptep, new_spte);
if (!is_rmap_spte(old_spte))
return;
return 0;
pfn = spte_to_pfn(old_spte);
if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
kvm_set_pfn_accessed(pfn);
if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask))
kvm_set_pfn_dirty(pfn);
return 1;
}
static void drop_spte(struct kvm *kvm, u64 *sptep, u64 new_spte)
{
set_spte_track_bits(sptep, new_spte);
rmap_remove(kvm, sptep);
if (set_spte_track_bits(sptep, new_spte))
rmap_remove(kvm, sptep);
}
static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)