Linux-PCI Archive on lore.kernel.org
 help / color / Atom feed
From: Kishon Vijay Abraham I <kishon@ti.com>
To: Ohad Ben-Cohen <ohad@wizery.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Jon Mason <jdmason@kudzu.us>, Dave Jiang <dave.jiang@intel.com>,
	Allen Hubbe <allenbh@gmail.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Stefano Garzarella <sgarzare@redhat.com>
Cc: <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-remoteproc@vger.kernel.org>, <linux-ntb@googlegroups.com>,
	<linux-pci@vger.kernel.org>, <kvm@vger.kernel.org>,
	<virtualization@lists.linux-foundation.org>,
	<netdev@vger.kernel.org>
Subject: [RFC PATCH 12/22] virtio: Add ops to allocate and free buffer
Date: Thu, 2 Jul 2020 13:51:33 +0530
Message-ID: <20200702082143.25259-13-kishon@ti.com> (raw)
In-Reply-To: <20200702082143.25259-1-kishon@ti.com>

Add ops to allocate and free buffer in struct virtio_config_ops.
Certain vhost devices can have restriction on the range of memory
it can access on the virtio. The virtio drivers attached to
such vhost devices reserves memory that can be accessed by
vhost. This function allocates buffer for such reserved region.

For instance when virtio-vhost is used by two hosts connected to
NTB, the vhost can access only memory exposed by memory windows
and the size of the memory window can be limited. Here the NTB
virtio driver can reserve a small region (few MBs) and provide
buffer address from this pool whenever requested by virtio client
driver.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 include/linux/virtio_config.h | 42 +++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index bb4cc4910750..419f733017c2 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -65,6 +65,9 @@ struct irq_affinity;
  *      the caller can then copy.
  * @set_vq_affinity: set the affinity for a virtqueue (optional).
  * @get_vq_affinity: get the affinity for a virtqueue (optional).
+ * @alloc_buffer: Allocate and provide buffer addresses that can be
+ *      accessed by both virtio and vhost
+ * @free_buffer: Free the allocated buffer address
  */
 typedef void vq_callback_t(struct virtqueue *);
 struct virtio_config_ops {
@@ -88,6 +91,9 @@ struct virtio_config_ops {
 			       const struct cpumask *cpu_mask);
 	const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
 			int index);
+	void * (*alloc_buffer)(struct virtio_device *vdev, size_t size);
+	void (*free_buffer)(struct virtio_device *vdev, void *addr,
+			    size_t size);
 };
 
 /* If driver didn't advertise the feature, it will never appear. */
@@ -232,6 +238,42 @@ const char *virtio_bus_name(struct virtio_device *vdev)
 	return vdev->config->bus_name(vdev);
 }
 
+/**
+ * virtio_alloc_buffer - Allocate buffer from the reserved memory
+ * @vdev: Virtio device which manages the reserved memory
+ * @size: Size of the buffer to be allocated
+ *
+ * Certain vhost devices can have restriction on the range of memory
+ * it can access on the virtio. The virtio drivers attached to
+ * such vhost devices reserves memory that can be accessed by
+ * vhost. This function allocates buffer for such reserved region.
+ */
+static inline void *
+virtio_alloc_buffer(struct virtio_device *vdev, size_t size)
+{
+	if (!vdev->config->alloc_buffer)
+		return NULL;
+
+	return vdev->config->alloc_buffer(vdev, size);
+}
+
+/**
+ * virtio_free_buffer - Free the allocated buffer
+ * @vdev: Virtio device which manages the reserved memory
+ * @addr: Address returned by virtio_alloc_buffer()
+ * @size: Size of the buffer that has to be freed
+ *
+ * Free the allocated buffer address given by virtio_alloc_buffer().
+ */
+static inline void
+virtio_free_buffer(struct virtio_device *vdev, void *addr, size_t size)
+{
+	if (!vdev->config->free_buffer)
+		return;
+
+	return vdev->config->free_buffer(vdev, addr, size);
+}
+
 /**
  * virtqueue_set_affinity - setting affinity for a virtqueue
  * @vq: the virtqueue
-- 
2.17.1


  parent reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-02  8:21 [RFC PATCH 00/22] Enhance VHOST to enable SoC-to-SoC communication Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 01/22] vhost: Make _feature_ bits a property of vhost device Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 02/22] vhost: Introduce standard Linux driver model in VHOST Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 03/22] vhost: Add ops for the VHOST driver to configure VHOST device Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 04/22] vringh: Add helpers to access vring in MMIO Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 05/22] vhost: Add MMIO helpers for operations on vhost virtqueue Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 06/22] vhost: Introduce configfs entry for configuring VHOST Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 07/22] virtio_pci: Use request_threaded_irq() instead of request_irq() Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 08/22] rpmsg: virtio_rpmsg_bus: Disable receive virtqueue callback when reading messages Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 09/22] rpmsg: Introduce configfs entry for configuring rpmsg Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 10/22] rpmsg: virtio_rpmsg_bus: Add Address Service Notification support Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 11/22] rpmsg: virtio_rpmsg_bus: Move generic rpmsg structure to rpmsg_internal.h Kishon Vijay Abraham I
2020-07-02  8:21 ` Kishon Vijay Abraham I [this message]
2020-07-02  8:21 ` [RFC PATCH 13/22] rpmsg: virtio_rpmsg_bus: Use virtio_alloc_buffer() and virtio_free_buffer() Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 14/22] rpmsg: Add VHOST based remote processor messaging bus Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 15/22] samples/rpmsg: Setup delayed work to send message Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 16/22] samples/rpmsg: Wait for address to be bound to rpdev for sending message Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 17/22] rpmsg.txt: Add Documentation to configure rpmsg using configfs Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 18/22] virtio_pci: Add VIRTIO driver for VHOST on Configurable PCIe Endpoint device Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 19/22] PCI: endpoint: Add EP function driver to provide VHOST interface Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 20/22] NTB: Add a new NTB client driver to implement VIRTIO functionality Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 21/22] NTB: Add a new NTB client driver to implement VHOST functionality Kishon Vijay Abraham I
2020-07-02  8:21 ` [RFC PATCH 22/22] NTB: Describe ntb_virtio and ntb_vhost client in the documentation Kishon Vijay Abraham I
2020-07-02  9:51 ` [RFC PATCH 00/22] Enhance VHOST to enable SoC-to-SoC communication Michael S. Tsirkin
2020-07-02 10:10   ` Jason Wang
2020-07-02 13:35     ` Kishon Vijay Abraham I
2020-07-03  7:16       ` Jason Wang
2020-07-06  9:32         ` Kishon Vijay Abraham I
2020-07-07  9:47           ` Jason Wang
2020-07-07 14:45             ` Kishon Vijay Abraham I
2020-07-08 11:22               ` Jason Wang
2020-07-08 13:13                 ` Kishon Vijay Abraham I
2020-07-09  6:26                   ` Jason Wang
2020-07-15 17:15                   ` Mathieu Poirier
2020-07-02 10:25   ` Kishon Vijay Abraham I
2020-07-02 17:31   ` Mathieu Poirier
2020-07-03  6:17     ` Kishon Vijay Abraham I

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200702082143.25259-13-kishon@ti.com \
    --to=kishon@ti.com \
    --cc=allenbh@gmail.com \
    --cc=bhelgaas@google.com \
    --cc=bjorn.andersson@linaro.org \
    --cc=dave.jiang@intel.com \
    --cc=jasowang@redhat.com \
    --cc=jdmason@kudzu.us \
    --cc=kvm@vger.kernel.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-ntb@googlegroups.com \
    --cc=linux-pci@vger.kernel.org \
    --cc=linux-remoteproc@vger.kernel.org \
    --cc=lorenzo.pieralisi@arm.com \
    --cc=mst@redhat.com \
    --cc=netdev@vger.kernel.org \
    --cc=ohad@wizery.com \
    --cc=pbonzini@redhat.com \
    --cc=sgarzare@redhat.com \
    --cc=stefanha@redhat.com \
    --cc=virtualization@lists.linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-PCI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-pci/0 linux-pci/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-pci linux-pci/ https://lore.kernel.org/linux-pci \
		linux-pci@vger.kernel.org
	public-inbox-index linux-pci

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-pci


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git