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* [PATCH] KVM: PPC: Book3S HV: Fix kvm_unmap_gfn_range_hv() for Hash MMU
@ 2021-05-11 10:54 Michael Ellerman
  2021-05-11 16:39 ` Sean Christopherson
  2021-05-15 22:43 ` Michael Ellerman
  0 siblings, 2 replies; 4+ messages in thread
From: Michael Ellerman @ 2021-05-11 10:54 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: npiggin, kvm, kvm-ppc, seanjc, pbonzini

Commit 32b48bf8514c ("KVM: PPC: Book3S HV: Fix conversion to gfn-based
MMU notifier callbacks") fixed kvm_unmap_gfn_range_hv() by adding a for
loop over each gfn in the range.

But for the Hash MMU it repeatedly calls kvm_unmap_rmapp() with the
first gfn of the range, rather than iterating through the range.

This exhibits as strange guest behaviour, sometimes crashing in firmare,
or booting and then guest userspace crashing unexpectedly.

Fix it by passing the iterator, gfn, to kvm_unmap_rmapp().

Fixes: 32b48bf8514c ("KVM: PPC: Book3S HV: Fix conversion to gfn-based MMU notifier callbacks")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kvm/book3s_64_mmu_hv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

I plan to take this via the powerpc fixes branch.

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 2d9193cd73be..c63e263312a4 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -840,7 +840,7 @@ bool kvm_unmap_gfn_range_hv(struct kvm *kvm, struct kvm_gfn_range *range)
 			kvm_unmap_radix(kvm, range->slot, gfn);
 	} else {
 		for (gfn = range->start; gfn < range->end; gfn++)
-			kvm_unmap_rmapp(kvm, range->slot, range->start);
+			kvm_unmap_rmapp(kvm, range->slot, gfn);
 	}
 
 	return false;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

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2021-05-11 10:54 [PATCH] KVM: PPC: Book3S HV: Fix kvm_unmap_gfn_range_hv() for Hash MMU Michael Ellerman
2021-05-11 16:39 ` Sean Christopherson
2021-05-12  3:20   ` Michael Ellerman
2021-05-15 22:43 ` Michael Ellerman

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