Patchwork KVM: PPC: Book3S HV: Allow DTL to be unregistered through KVM_SET_ONE_REG interface

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Submitter Paul Mackerras
Date Sept. 28, 2012, 5:29 a.m.
Message ID <20120928052911.GA4852@bloggs.ozlabs.ibm.com>
Download mbox | patch
Permalink /patch/187718/
State New
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Comments

Paul Mackerras - Sept. 28, 2012, 5:29 a.m.
From 0912ff6f7d95aa559af75ba69aa7f661357f5dce Mon Sep 17 00:00:00 2001
From: Paul Mackerras <paulus@samba.org>
Date: Fri, 28 Sep 2012 15:26:07 +1000
Subject: [PATCH] KVM: PPC: Book3S HV: Allow DTL to be set to address 0,
 length 0

Recently-added code to allow the dispatch trace log buffer address
to be set with the KVM_SET_ONE_REG interface includes a check on
the length 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,
so this makes the check conditional on the address being non-zero.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
 arch/powerpc/kvm/book3s_hv.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Patch

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 350b038..1eda13d 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -854,9 +854,8 @@  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);