[PATCH 1/6] KVM: PPC: Book3S HV: XIVE: initialize private pointer when VPs are allocated

From: Greg Kurz <groug@kaod.org>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: "Michael Ellerman" <mpe@ellerman.id.au>,
	"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Cédric Le Goater" <clg@kaod.org>,
	"David Gibson" <david@gibson.dropbear.id.au>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	kvm-ppc@vger.kernel.org, kvm@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 1/6] KVM: PPC: Book3S HV: XIVE: initialize private pointer when VPs are allocated
Date: Mon, 23 Sep 2019 17:43:37 +0200	[thread overview]
Message-ID: <156925341736.974393.18379970954169086891.stgit@bahia.lan> (raw)
In-Reply-To: <156925341155.974393.11681611197111945710.stgit@bahia.lan>

From: Cédric Le Goater <clg@kaod.org>

Do not assign the device private pointer before making sure the XIVE
VPs are allocated in OPAL and test pointer validity when releasing
the device.

Fixes: 5422e95103cf ("KVM: PPC: Book3S HV: XIVE: Replace the 'destroy' method by a 'release' method")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
---
 arch/powerpc/kvm/book3s_xive.c        |   13 +++++++++++--
 arch/powerpc/kvm/book3s_xive_native.c |   13 +++++++++++--
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
index 591bfb4bfd0f..cd2006bfcd3e 100644
--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -1897,12 +1897,21 @@ void kvmppc_xive_free_sources(struct kvmppc_xive_src_block *sb)
 static void kvmppc_xive_release(struct kvm_device *dev)
 {
 	struct kvmppc_xive *xive = dev->private;
-	struct kvm *kvm = xive->kvm;
+	struct kvm *kvm;
 	struct kvm_vcpu *vcpu;
 	int i;
 
 	pr_devel("Releasing xive device\n");
 
+	/*
+	 * In case of failure (OPAL) at device creation, the device
+	 * can be partially initialized.
+	 */
+	if (!xive)
+		return;
+
+	kvm = xive->kvm;
+
 	/*
 	 * Since this is the device release function, we know that
 	 * userspace does not have any open fd referring to the
@@ -2001,7 +2010,6 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
 	if (!xive)
 		return -ENOMEM;
 
-	dev->private = xive;
 	xive->dev = dev;
 	xive->kvm = kvm;
 	mutex_init(&xive->lock);
@@ -2031,6 +2039,7 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
 	if (ret)
 		return ret;
 
+	dev->private = xive;
 	return 0;
 }
 
diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
index 248c1ea9e788..e9cbb42de424 100644
--- a/arch/powerpc/kvm/book3s_xive_native.c
+++ b/arch/powerpc/kvm/book3s_xive_native.c
@@ -987,12 +987,21 @@ static int kvmppc_xive_native_has_attr(struct kvm_device *dev,
 static void kvmppc_xive_native_release(struct kvm_device *dev)
 {
 	struct kvmppc_xive *xive = dev->private;
-	struct kvm *kvm = xive->kvm;
+	struct kvm *kvm;
 	struct kvm_vcpu *vcpu;
 	int i;
 
 	pr_devel("Releasing xive native device\n");
 
+	/*
+	 * In case of failure (OPAL) at device creation, the device
+	 * can be partially initialized.
+	 */
+	if (!xive)
+		return;
+
+	kvm = xive->kvm;
+
 	/*
 	 * Clear the KVM device file address_space which is used to
 	 * unmap the ESB pages when a device is passed-through.
@@ -1076,7 +1085,6 @@ static int kvmppc_xive_native_create(struct kvm_device *dev, u32 type)
 	if (!xive)
 		return -ENOMEM;
 
-	dev->private = xive;
 	xive->dev = dev;
 	xive->kvm = kvm;
 	kvm->arch.xive = xive;
@@ -1100,6 +1108,7 @@ static int kvmppc_xive_native_create(struct kvm_device *dev, u32 type)
 	if (ret)
 		return ret;
 
+	dev->private = xive;
 	return 0;
 }
 

