Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933397AbbLGQU4 (ORCPT ); Mon, 7 Dec 2015 11:20:56 -0500 Received: from smtp.citrix.com ([66.165.176.89]:5980 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755725AbbLGQUt (ORCPT ); Mon, 7 Dec 2015 11:20:49 -0500 X-IronPort-AV: E=Sophos;i="5.20,395,1444694400"; d="scan'208";a="317073636" From: Stefano Stabellini To: CC: , , , , Stefano Stabellini Subject: [PATCH RFC 3/3] xen/virtio_ring: introduce cpu_to_virtio_addr and virtio_addr_to_cpu Date: Mon, 7 Dec 2015 16:19:43 +0000 Message-ID: <1449505183-29740-3-git-send-email-stefano.stabellini@eu.citrix.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5178 Lines: 121 When running on Xen inside as virtual machine (nested virt scenario), addresses need to be translated from phys to machine to get the actual guest pseudo-physical address. Introduce a new pair of functions, cpu_to_virtio_addr and virtio_addr_to_cpu, which call the appriopriate __virtio64_to_cpu and __cpu_to_virtio64 functions after doing the phys_to_bus and bus_to_phys translations for Xen. No changes in behavior for the non-Xen case. Signed-off-by: Stefano Stabellini --- I realize that this patch is not very nice, but at least it is easy to understand. I welcome any suggestions on how to improve it. I considered introducing regular dma API calls, like dma_map/unmap_single and dma_map/unmap_sg. However they would make the non-Xen code path more complex than it is today. We would also need to keep track of the physical or virtual address in addition to the dma address for each vring_desc to be able to free the memory in detach_buf. --- drivers/virtio/virtio_ring.c | 9 +++++---- include/linux/virtio_config.h | 14 ++++++++++++++ 2 files changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 096b857..34a1d42 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -16,6 +16,7 @@ * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ +#include #include #include #include @@ -172,7 +173,7 @@ static inline int virtqueue_add(struct virtqueue *_vq, if (desc) { /* Use a single buffer which doesn't continue */ vq->vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT); - vq->vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, virt_to_phys(desc)); + vq->vring.desc[head].addr = cpu_to_virtio_addr(_vq->vdev, virt_to_phys(desc)); /* avoid kmemleak false positive (hidden by virt_to_phys) */ kmemleak_ignore(desc); vq->vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc)); @@ -206,7 +207,7 @@ static inline int virtqueue_add(struct virtqueue *_vq, for (n = 0; n < out_sgs; n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT); - desc[i].addr = cpu_to_virtio64(_vq->vdev, sg_phys(sg)); + desc[i].addr = cpu_to_virtio_addr(_vq->vdev, sg_phys(sg)); desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); prev = i; i = virtio16_to_cpu(_vq->vdev, desc[i].next); @@ -215,7 +216,7 @@ static inline int virtqueue_add(struct virtqueue *_vq, for (; n < (out_sgs + in_sgs); n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE); - desc[i].addr = cpu_to_virtio64(_vq->vdev, sg_phys(sg)); + desc[i].addr = cpu_to_virtio_addr(_vq->vdev, sg_phys(sg)); desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); prev = i; i = virtio16_to_cpu(_vq->vdev, desc[i].next); @@ -433,7 +434,7 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head) /* Free the indirect table */ if (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT)) - kfree(phys_to_virt(virtio64_to_cpu(vq->vq.vdev, vq->vring.desc[i].addr))); + kfree(phys_to_virt(virtio_addr_to_cpu(vq->vq.vdev, vq->vring.desc[i].addr))); while (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT)) { i = virtio16_to_cpu(vq->vq.vdev, vq->vring.desc[i].next); diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index e5ce8ab..861803f 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -6,6 +6,8 @@ #include #include #include +#include +#include /** * virtio_config_ops - operations for configuring a virtio device @@ -237,11 +239,23 @@ static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val) return __virtio64_to_cpu(virtio_is_little_endian(vdev), val); } +static inline u64 virtio_addr_to_cpu(struct virtio_device *vdev, __virtio64 val) +{ + val = xen_pv_domain() ? xen_bus_to_phys(val) : val; + return __virtio64_to_cpu(virtio_is_little_endian(vdev), val); +} + static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) { return __cpu_to_virtio64(virtio_is_little_endian(vdev), val); } +static inline __virtio64 cpu_to_virtio_addr(struct virtio_device *vdev, u64 val) +{ + val = xen_pv_domain() ? xen_phys_to_bus(val) : val; + return __cpu_to_virtio64(virtio_is_little_endian(vdev), val); +} + /* Config space accessors. */ #define virtio_cread(vdev, structname, member, ptr) \ do { \ -- 1.7.10.4 -- 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/