linux-kernel - Re: s390 kvm_virtio.c build error

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <200805051019.02289.rusty@rustcorp.com.au>
Date:	Mon, 5 May 2008 10:19:01 +1000
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Adrian Bunk <bunk@...nel.org>
Cc:	Christian Borntraeger <borntraeger@...ibm.com>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	Carsten Otte <cotte@...ibm.com>, Avi Kivity <avi@...ranet.com>,
	kvm-devel@...ts.sourceforge.net, linux-s390@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: s390 kvm_virtio.c build error

On Sunday 04 May 2008 03:47:17 Adrian Bunk wrote:
> Commit c45a6816c19dee67b8f725e6646d428901a6dc24
> (virtio: explicit advertisement of driver features)
> and commit e976a2b997fc4ad70ccc53acfe62811c4aaec851
> (s390: KVM guest: virtio device support, and kvm hypercalls)
> don't like each other:

Yep, I broke s390.  This was kind of expected, but I didn't want to try to
fix it as I am unable to test.

It would look something like this:

virtio: Attempt to fix kvm_virtio after feature management changes

Very similar to lguest code: set and get feature are now separate callbacks.

Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>

diff -r 219d6c116996 drivers/s390/kvm/kvm_virtio.c
--- a/drivers/s390/kvm/kvm_virtio.c	Mon May 05 10:03:16 2008 +1000
+++ b/drivers/s390/kvm/kvm_virtio.c	Mon May 05 10:17:25 2008 +1000
@@ -78,27 +78,34 @@ static unsigned desc_size(const struct k
 		+ desc->config_len;
 }
 
-/*
- * This tests (and acknowleges) a feature bit.
- */
-static bool kvm_feature(struct virtio_device *vdev, unsigned fbit)
+/* This gets the device's feature bits. */
+static u32 kvm_get_features(struct virtio_device *vdev)
 {
+	unsigned int i;
+	u32 features = 0;
 	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
-	u8 *features;
+	u8 *in_features = kvm_vq_features(desc);
 
-	if (fbit / 8 > desc->feature_len)
-		return false;
+	/* We do this the slow but generic way. */
+	for (i = 0; i < min(desc->feature_len * 8, 32); i++)
+		if (in_features[i / 8] & (1 << (i % 8)))
+			features |= (1 << i);
 
-	features = kvm_vq_features(desc);
-	if (!(features[fbit / 8] & (1 << (fbit % 8))))
-		return false;
+	return features;
+}
 
-	/*
-	 * We set the matching bit in the other half of the bitmap to tell the
-	 * Host we want to use this feature.
-	 */
-	features[desc->feature_len + fbit / 8] |= (1 << (fbit % 8));
-	return true;
+static void kvm_set_features(struct virtio_device *vdev, u32 features)
+{
+	unsigned int i;
+	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
+	/* Second half of bitmap is features we accept. */
+	u8 *out_features = kvm_vq_features(desc) + desc->feature_len;
+
+	memset(out_features, 0, desc->feature_len);
+	for (i = 0; i < min(desc->feature_len * 8, 32); i++) {
+		if (features & (1 << i))
+			out_features[i / 8] |= (1 << (i % 8));
+	}
 }
 
 /*
@@ -221,7 +228,8 @@ static void kvm_del_vq(struct virtqueue 
  * The config ops structure as defined by virtio config
  */
 static struct virtio_config_ops kvm_vq_configspace_ops = {
-	.feature = kvm_feature,
+	.get_features = kvm_get_features,
+	.set_features = kvm_set_features,
 	.get = kvm_get,
 	.set = kvm_set,
 	.get_status = kvm_get_status,
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/