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| author | Marcelo Tosatti <mtosatti@redhat.com> | 2010-10-25 11:58:22 -0200 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2010-11-05 14:42:26 -0200 |
| commit | eb45fda45f915c7ca3e81e005e853cb770da2642 (patch) | |
| tree | 9c10bbdb52a1a1752cac30343a3c6f4d79ef4a88 /arch/x86 | |
| parent | edde99ce05290e50ce0b3495d209e54e6349ab47 (diff) | |
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>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 908ea5464a5..fb8b376bf28 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -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) |