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| author | Paul Mackerras <paulus@ozlabs.org> | 2018-02-07 11:49:54 +0300 |
|---|---|---|
| committer | Paul Mackerras <paulus@ozlabs.org> | 2018-02-09 07:35:24 +0300 |
| commit | 05f2bb0313a2855e491dadfc8319b7da261d7074 (patch) | |
| tree | 5e75fbfcc885ae5235eaaef4ef2ef310160ab56d /arch | |
| parent | 57ea5f161a7de5b1913c212d04f57a175b159fdf (diff) | |
| download | linux-05f2bb0313a2855e491dadfc8319b7da261d7074.tar.xz | |
KVM: PPC: Book3S HV: Fix handling of secondary HPTEG in HPT resizing code
This fixes the computation of the HPTE index to use when the HPT
resizing code encounters a bolted HPTE which is stored in its
secondary HPTE group. The code inverts the HPTE group number, which
is correct, but doesn't then mask it with new_hash_mask. As a result,
new_pteg will be effectively negative, resulting in new_hptep
pointing before the new HPT, which will corrupt memory.
In addition, this removes two BUG_ON statements. The condition that
the BUG_ONs were testing -- that we have computed the hash value
incorrectly -- has never been observed in testing, and if it did
occur, would only affect the guest, not the host. Given that
BUG_ON should only be used in conditions where the kernel (i.e.
the host kernel, in this case) can't possibly continue execution,
it is not appropriate here.
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_hv.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 966097232d21..d19649960bbf 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -1329,12 +1329,8 @@ static unsigned long resize_hpt_rehash_hpte(struct kvm_resize_hpt *resize, } new_pteg = hash & new_hash_mask; - if (vpte & HPTE_V_SECONDARY) { - BUG_ON(~pteg != (hash & old_hash_mask)); - new_pteg = ~new_pteg; - } else { - BUG_ON(pteg != (hash & old_hash_mask)); - } + if (vpte & HPTE_V_SECONDARY) + new_pteg = ~hash & new_hash_mask; new_idx = new_pteg * HPTES_PER_GROUP + (idx % HPTES_PER_GROUP); new_hptep = (__be64 *)(new->virt + (new_idx << 4)); |