From 9f8c8c7812976fbfaf4bb30aaf8f6b001864f20a Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Mon, 15 Oct 2012 01:18:37 +0000 Subject: [PATCH] KVM: PPC: Book3S HV: Allow DTL to be set to address 0, length 0 Commit 55b665b026 ("KVM: PPC: Book3S HV: Provide a way for userspace to get/set per-vCPU areas") includes a check on the length of the dispatch trace log (DTL) to make sure the buffer is at least one entry long. This is appropriate when registering a buffer, but the interface also allows for any existing buffer to be unregistered by specifying a zero address. In this case the length check is not appropriate. This makes the check conditional on the address being non-zero. Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s_hv.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 8b3c470e6cb91..812764c96229c 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -811,9 +811,8 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val) addr = val->vpaval.addr; len = val->vpaval.length; r = -EINVAL; - if (len < sizeof(struct dtl_entry)) - break; - if (addr && !vcpu->arch.vpa.next_gpa) + if (addr && (len < sizeof(struct dtl_entry) || + !vcpu->arch.vpa.next_gpa)) break; len -= len % sizeof(struct dtl_entry); r = set_vpa(vcpu, &vcpu->arch.dtl, addr, len);