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KVM: PPC: Book3S HV: Fix bug leading to deadlock in guest HPT updates

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When handling the H_BULK_REMOVE hypercall, we were forgetting to
invalidate and unlock the hashed page table entry (HPTE) in the case
where the page had been paged out.  This fixes it by clearing the
first doubleword of the HPTE in that case.

This fixes a regression introduced in commit a92bce95f0 ("KVM: PPC:
Book3S HV: Keep HPTE locked when invalidating").  The effect of the
regression is that the host kernel will sometimes hang when under
memory pressure.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Paul Mackerras 2012-05-09 23:49:24 +00:00 committed by Alexander Graf
parent ffe3649282
commit 51bfd29981
1 changed files with 1 additions and 0 deletions
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arch/powerpc/kvm/book3s_hv_rm_mmu.c
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@ -463,6 +463,7 @@ long kvmppc_h_bulk_remove(struct kvm_vcpu *vcpu)
/* insert R and C bits from PTE */ /* insert R and C bits from PTE */
rcbits = rev->guest_rpte & (HPTE_R_R|HPTE_R_C); rcbits = rev->guest_rpte & (HPTE_R_R|HPTE_R_C);
args[j] |= rcbits << (56 - 5); args[j] |= rcbits << (56 - 5);
hp[0] = 0;
continue; continue;
} }