Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753422AbbDAKgE (ORCPT ); Wed, 1 Apr 2015 06:36:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56001 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752695AbbDAKf7 (ORCPT ); Wed, 1 Apr 2015 06:35:59 -0400 Date: Wed, 1 Apr 2015 12:35:45 +0200 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Cornelia Huck , Pawel Moll , virtio-dev@lists.oasis-open.org, Rusty Russell , virtualization@lists.linux-foundation.org, linux-api@vger.kernel.org Subject: [PATCH v3 1/6] virtio_balloon: transitional interface Message-ID: <1427884468-23930-2-git-send-email-mst@redhat.com> References: <1427884468-23930-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1427884468-23930-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4895 Lines: 151 Virtio 1.0 doesn't include a modern balloon device. But it's not a big change to support a transitional balloon device: this has the advantage of supporting existing drivers, transparently. Signed-off-by: Michael S. Tsirkin --- include/uapi/linux/virtio_balloon.h | 11 ++++++++-- drivers/virtio/virtio_balloon.c | 43 +++++++++++++++++++++++++++++-------- 2 files changed, 43 insertions(+), 11 deletions(-) diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h index 4b0488f..f81b220 100644 --- a/include/uapi/linux/virtio_balloon.h +++ b/include/uapi/linux/virtio_balloon.h @@ -25,6 +25,7 @@ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ +#include #include #include @@ -38,9 +39,9 @@ struct virtio_balloon_config { /* Number of pages host wants Guest to give up. */ - __le32 num_pages; + __u32 num_pages; /* Number of pages we've actually got in balloon. */ - __le32 actual; + __u32 actual; }; #define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */ @@ -56,4 +57,10 @@ struct virtio_balloon_stat { __u64 val; } __attribute__((packed)); +struct virtio_balloon_stat_modern { + __le16 tag; + __u8 reserved[6]; + __le64 val; +}; + #endif /* _LINUX_VIRTIO_BALLOON_H */ diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 6a356e3..0583720 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -77,7 +77,10 @@ struct virtio_balloon { /* Memory statistics */ int need_stats_update; - struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; + union { + struct virtio_balloon_stat_modern stats[VIRTIO_BALLOON_S_NR]; + struct virtio_balloon_stat legacy_stats[VIRTIO_BALLOON_S_NR]; + }; /* To register callback in oom notifier call chain */ struct notifier_block nb; @@ -88,6 +91,14 @@ static struct virtio_device_id id_table[] = { { 0 }, }; +static void stats_sg_init(struct virtio_balloon *vb, struct scatterlist *sg) +{ + if (virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1)) + sg_init_one(sg, vb->stats, sizeof(vb->stats)); + else + sg_init_one(sg, vb->legacy_stats, sizeof(vb->legacy_stats)); +} + static u32 page_to_balloon_pfn(struct page *page) { unsigned long pfn = page_to_pfn(page); @@ -214,8 +225,13 @@ static inline void update_stat(struct virtio_balloon *vb, int idx, u16 tag, u64 val) { BUG_ON(idx >= VIRTIO_BALLOON_S_NR); - vb->stats[idx].tag = tag; - vb->stats[idx].val = val; + if (virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1)) { + vb->stats[idx].tag = cpu_to_le32(tag); + vb->stats[idx].val = cpu_to_le64(val); + } else { + vb->legacy_stats[idx].tag = tag; + vb->legacy_stats[idx].val = val; + } } #define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT) @@ -269,7 +285,7 @@ static void stats_handle_request(struct virtio_balloon *vb) vq = vb->stats_vq; if (!virtqueue_get_buf(vq, &len)) return; - sg_init_one(&sg, vb->stats, sizeof(vb->stats)); + stats_sg_init(vb, &sg); virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); virtqueue_kick(vq); } @@ -283,18 +299,27 @@ static void virtballoon_changed(struct virtio_device *vdev) static inline s64 towards_target(struct virtio_balloon *vb) { - __le32 v; s64 target; + u32 num_pages; + + virtio_cread(vb->vdev, struct virtio_balloon_config, num_pages, + &num_pages); - virtio_cread(vb->vdev, struct virtio_balloon_config, num_pages, &v); + /* Legacy balloon config space is LE, unlike all other devices. */ + if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1)) + num_pages = le32_to_cpu((__force __le32)num_pages); - target = le32_to_cpu(v); + target = num_pages; return target - vb->num_pages; } static void update_balloon_size(struct virtio_balloon *vb) { - __le32 actual = cpu_to_le32(vb->num_pages); + u32 actual = vb->num_pages; + + /* Legacy balloon config space is LE, unlike all other devices. */ + if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1)) + actual = (__force u32)cpu_to_le32(actual); virtio_cwrite(vb->vdev, struct virtio_balloon_config, actual, &actual); @@ -397,7 +422,7 @@ static int init_vqs(struct virtio_balloon *vb) * Prime this virtqueue with one buffer so the hypervisor can * use it to signal us later (it can't be broken yet!). */ - sg_init_one(&sg, vb->stats, sizeof vb->stats); + stats_sg_init(vb, &sg); if (virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, GFP_KERNEL) < 0) BUG(); -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/