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SubjectRe: [V9fs-developer] [kvm-devel] [RFC] 9p: add KVM/QEMU pci transport
That's also in our plans. There was no virtio support in KVM when I
started working in the transport.

Thanks,
Lucho

On 8/29/07, Anthony Liguori <anthony@codemonkey.ws> wrote:
> I think that it would be nicer to implement the p9 transport on top of
> virtio instead of directly on top of PCI. I think your PCI transport
> would make a pretty nice start of a PCI virtio transport though.
>
> Regards,
>
> Anthony Liguori
>
> On Tue, 2007-08-28 at 13:52 -0500, Eric Van Hensbergen wrote:
> > From: Latchesar Ionkov <lucho@ionkov.net>
> >
> > This adds a shared memory transport for a synthetic 9p device for
> > paravirtualized file system support under KVM/QEMU.
> >
> > Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
> > Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
> > ---
> > Documentation/filesystems/9p.txt | 2 +
> > net/9p/Kconfig | 10 ++-
> > net/9p/Makefile | 4 +
> > net/9p/trans_pci.c | 295 ++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 310 insertions(+), 1 deletions(-)
> > create mode 100644 net/9p/trans_pci.c
> >
> > diff --git a/Documentation/filesystems/9p.txt b/Documentation/filesystems/9p.txt
> > index 1a5f50d..e1879bd 100644
> > --- a/Documentation/filesystems/9p.txt
> > +++ b/Documentation/filesystems/9p.txt
> > @@ -46,6 +46,8 @@ OPTIONS
> > tcp - specifying a normal TCP/IP connection
> > fd - used passed file descriptors for connection
> > (see rfdno and wfdno)
> > + pci - use a PCI pseudo device for 9p communication
> > + over shared memory between a guest and host
> >
> > uname=name user name to attempt mount as on the remote server. The
> > server may override or ignore this value. Certain user
> > diff --git a/net/9p/Kconfig b/net/9p/Kconfig
> > index 09566ae..8517560 100644
> > --- a/net/9p/Kconfig
> > +++ b/net/9p/Kconfig
> > @@ -16,13 +16,21 @@ menuconfig NET_9P
> > config NET_9P_FD
> > depends on NET_9P
> > default y if NET_9P
> > - tristate "9P File Descriptor Transports (Experimental)"
> > + tristate "9p File Descriptor Transports (Experimental)"
> > help
> > This builds support for file descriptor transports for 9p
> > which includes support for TCP/IP, named pipes, or passed
> > file descriptors. TCP/IP is the default transport for 9p,
> > so if you are going to use 9p, you'll likely want this.
> >
> > +config NET_9P_PCI
> > + depends on NET_9P
> > + tristate "9p PCI Shared Memory Transport (Experimental)"
> > + help
> > + This builds support for a PCI psuedo-device currently available
> > + under KVM/QEMU which allows for 9p transactions over shared
> > + memory between the guest and the host.
> > +
> > config NET_9P_DEBUG
> > bool "Debug information"
> > depends on NET_9P
> > diff --git a/net/9p/Makefile b/net/9p/Makefile
> > index 7b2a67a..26ce89d 100644
> > --- a/net/9p/Makefile
> > +++ b/net/9p/Makefile
> > @@ -1,5 +1,6 @@
> > obj-$(CONFIG_NET_9P) := 9pnet.o
> > obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
> > +obj-$(CONFIG_NET_9P_PCI) += 9pnet_pci.o
> >
> > 9pnet-objs := \
> > mod.o \
> > @@ -14,3 +15,6 @@ obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
> >
> > 9pnet_fd-objs := \
> > trans_fd.o \
> > +
> > +9pnet_pci-objs := \
> > + trans_pci.o \
> > diff --git a/net/9p/trans_pci.c b/net/9p/trans_pci.c
> > new file mode 100644
> > index 0000000..36ddc5f
> > --- /dev/null
> > +++ b/net/9p/trans_pci.c
> > @@ -0,0 +1,295 @@
> > +/*
> > + * net/9p/trans_pci.c
> > + *
> > + * 9P over PCI transport layer. For use with KVM/QEMU.
> > + *
> > + * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2
> > + * as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to:
> > + * Free Software Foundation
> > + * 51 Franklin Street, Fifth Floor
> > + * Boston, MA 02111-1301 USA
> > + *
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/compiler.h>
> > +#include <linux/pci.h>
> > +#include <linux/init.h>
> > +#include <linux/ioport.h>
> > +#include <linux/completion.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/uaccess.h>
> > +#include <linux/irq.h>
> > +#include <linux/poll.h>
> > +#include <net/9p/9p.h>
> > +#include <net/9p/transport.h>
> > +
> > +#define P9PCI_DRIVER_NAME "9P PCI Device"
> > +#define P9PCI_DRIVER_VERSION "1"
> > +
> > +#define PCI_VENDOR_ID_9P 0x5002
> > +#define PCI_DEVICE_ID_9P 0x000D
> > +
> > +#define MAX_PCI_BUF (4*1024) /* TODO: Get a number from lucho */
> > +
> > +struct p9pci_trans {
> > + struct pci_dev *pdev;
> > + void __iomem *ioaddr;
> > + void __iomem *tx;
> > + void __iomem *rx;
> > + int irq;
> > + int pos;
> > + int len;
> > + wait_queue_head_t wait;
> > +};
> > +static struct p9pci_trans *p9pci_trans; /* single channel for now */
> > +
> > +static struct pci_device_id p9pci_tbl[] = {
> > + {PCI_VENDOR_ID_9P, PCI_DEVICE_ID_9P, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
> > + {0,}
> > +};
> > +
> > +static irqreturn_t p9pci_interrupt(int irq, void *dev)
> > +{
> > + p9pci_trans = dev;
> > + p9pci_trans->len = le32_to_cpu(readl(p9pci_trans->rx));
> > + P9_DPRINTK(P9_DEBUG_TRANS, "%p len %d\n", p9pci_trans->pdev,
> > + p9pci_trans->len);
> > + iowrite32(0, p9pci_trans->ioaddr + 4);
> > + wake_up_interruptible(&p9pci_trans->wait);
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int p9pci_read(struct p9_trans *trans, void *v, int len)
> > +{
> > + struct p9pci_trans *ts;
> > +
> > + if (!trans || trans->status == Disconnected || !trans->priv)
> > + return -EREMOTEIO;
> > +
> > + ts = trans->priv;
> > +
> > + P9_DPRINTK(P9_DEBUG_TRANS, "trans %p rx %p tx %p buf %p len %d\n",
> > + trans, ts->rx, ts->tx, v, len);
> > + if (len > ts->len)
> > + len = ts->len;
> > +
> > + if (len) {
> > + memcpy_fromio(v, ts->rx, len);
> > + ts->len = 0;
> > + /* let the host knows the message is consumed */
> > + writel(0, ts->rx);
> > + iowrite32(0, p9pci_trans->ioaddr + 4);
> > + P9_DPRINTK(P9_DEBUG_TRANS, "zero rxlen %d txlen %d\n",
> > + readl(ts->rx), readl(ts->tx));
> > + }
> > +
> > + return len;
> > +}
> > +
> > +static int p9pci_write(struct p9_trans *trans, void *v, int len)
> > +{
> > + struct p9pci_trans *ts;
> > +
> > + if (!trans || trans->status == Disconnected || !trans->priv)
> > + return -EREMOTEIO;
> > +
> > + ts = trans->priv;
> > + P9_DPRINTK(P9_DEBUG_TRANS, "trans %p rx %p tx %p buf %p len %d\n",
> > + trans, ts->rx, ts->tx, v, len);
> > + P9_DPRINTK(P9_DEBUG_TRANS, "rxlen %d\n", readl(ts->rx));
> > + if (readb(ts->tx) != 0)
> > + return 0;
> > +
> > + P9_DPRINTK(P9_DEBUG_TRANS, "tx addr %p io addr %p\n", ts->tx,
> > + ts->ioaddr);
> > + memcpy_toio(ts->tx, v, len);
> > + iowrite32(len, ts->ioaddr);
> > + return len;
> > +}
> > +
> > +static unsigned int
> > +p9pci_poll(struct p9_trans *trans, struct poll_table_struct *pt)
> > +{
> > + int ret;
> > + struct p9pci_trans *ts;
> > +
> > + P9_DPRINTK(P9_DEBUG_TRANS, "trans %p\n", trans);
> > + if (!trans || trans->status != Connected || !trans->priv)
> > + return -EREMOTEIO;
> > +
> > + ts = trans->priv;
> > + poll_wait(NULL, &ts->wait, pt);
> > + ret = 0;
> > + if (!readl(ts->tx))
> > + ret |= POLLOUT;
> > + if (readl(ts->rx))
> > + ret |= POLLIN;
> > +
> > + P9_DPRINTK(P9_DEBUG_TRANS, "txlen %d rxlen %d\n", readl(ts->tx),
> > + readl(ts->rx));
> > + return ret;
> > +}
> > +
> > +/**
> > + * p9_sock_close - shutdown socket
> > + * @trans: private socket structure
> > + *
> > + */
> > +static void p9pci_close(struct p9_trans *trans)
> > +{
> > + P9_DPRINTK(P9_DEBUG_TRANS, "trans %p\n", trans);
> > +}
> > +
> > +static struct p9_trans *p9pci_trans_create(const char *name, char *arg)
> > +{
> > + struct p9_trans *trans;
> > +
> > + P9_DPRINTK(P9_DEBUG_TRANS, "\n");
> > + trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
> > + if (!trans)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + trans->status = Connected;
> > + trans->write = p9pci_write;
> > + trans->read = p9pci_read;
> > + trans->close = p9pci_close;
> > + trans->poll = p9pci_poll;
> > + trans->priv = p9pci_trans;
> > + writel(0, p9pci_trans->tx);
> > + writel(0, p9pci_trans->rx);
> > +
> > + return trans;
> > +}
> > +
> > +static int __devinit p9pci_probe(struct pci_dev *pdev,
> > + const struct pci_device_id *ent)
> > +{
> > + int err;
> > + u8 pci_rev;
> > +
> > + if (p9pci_trans)
> > + return -1;
> > +
> > + pci_read_config_byte(pdev, PCI_REVISION_ID, &pci_rev);
> > +
> > + if (pdev->vendor == PCI_VENDOR_ID_9P &&
> > + pdev->device == PCI_DEVICE_ID_9P)
> > + printk(KERN_INFO "pci dev %s (id %04x:%04x rev %02x) is a 9P\n",
> > + pci_name(pdev), pdev->vendor, pdev->device, pci_rev);
> > +
> > + P9_DPRINTK(P9_DEBUG_TRANS, "%p\n", pdev);
> > + p9pci_trans = kzalloc(sizeof(*p9pci_trans), GFP_KERNEL);
> > + p9pci_trans->irq = -1;
> > + init_waitqueue_head(&p9pci_trans->wait);
> > + err = pci_enable_device(pdev);
> > + if (err)
> > + goto error;
> > +
> > + p9pci_trans->pdev = pdev;
> > + err = pci_request_regions(pdev, "9p");
> > + if (err)
> > + goto error;
> > +
> > + p9pci_trans->ioaddr = pci_iomap(pdev, 0, 8);
> > + if (!p9pci_trans->ioaddr) {
> > + P9_DPRINTK(P9_DEBUG_ERROR, "Cannot remap MMIO, aborting\n");
> > + err = -EIO;
> > + goto error;
> > + }
> > +
> > + p9pci_trans->tx = pci_iomap(pdev, 1, 0x20000);
> > + p9pci_trans->rx = pci_iomap(pdev, 2, 0x20000);
> > + pci_set_drvdata(pdev, p9pci_trans);
> > + err = request_irq(pdev->irq, &p9pci_interrupt, 0, "p9pci", p9pci_trans);
> > + if (err)
> > + goto error;
> > +
> > + p9pci_trans->irq = pdev->irq;
> > + return 0;
> > +
> > +error:
> > + P9_DPRINTK(P9_DEBUG_ERROR, "error %d\n", err);
> > + if (p9pci_trans->irq >= 0) {
> > + synchronize_irq(p9pci_trans->irq);
> > + free_irq(p9pci_trans->irq, p9pci_trans);
> > + }
> > +
> > + if (p9pci_trans->pdev) {
> > + pci_release_regions(pdev);
> > + pci_iounmap(pdev, p9pci_trans->ioaddr);
> > + pci_set_drvdata(pdev, NULL);
> > + pci_disable_device(pdev);
> > + }
> > +
> > + kfree(p9pci_trans);
> > + return -1;
> > +}
> > +
> > +static void __devexit p9pci_remove(struct pci_dev *pdev)
> > +{
> > + P9_DPRINTK(P9_DEBUG_TRANS, "%p\n", pdev);
> > + p9pci_trans = pci_get_drvdata(pdev);
> > + if (!p9pci_trans)
> > + return;
> > +
> > + if (p9pci_trans->irq) {
> > + synchronize_irq(p9pci_trans->irq);
> > + free_irq(p9pci_trans->irq, p9pci_trans);
> > + }
> > +
> > + pci_release_regions(pdev);
> > + pci_iounmap(pdev, p9pci_trans->ioaddr);
> > + pci_set_drvdata(pdev, NULL);
> > + kfree(p9pci_trans);
> > + pci_disable_device(pdev);
> > +}
> > +
> > +static struct pci_driver p9pci_driver = {
> > + .name = P9PCI_DRIVER_NAME,
> > + .id_table = p9pci_tbl,
> > + .probe = p9pci_probe,
> > + .remove = __devexit_p(p9pci_remove),
> > +};
> > +
> > +static struct p9_trans_module p9_pci_trans = {
> > + .name = "pci",
> > + .maxsize = MAX_PCI_BUF,
> > + .def = 0,
> > + .create = p9pci_trans_create,
> > +};
> > +
> > +static int __init p9pci_init_module(void)
> > +{
> > + v9fs_register_trans(&p9_pci_trans);
> > + return pci_register_driver(&p9pci_driver);
> > +}
> > +
> > +static void __exit p9pci_cleanup_module(void)
> > +{
> > + pci_unregister_driver(&p9pci_driver);
> > + printk(KERN_ERR "Removal of 9p transports not implemented\n");
> > + BUG();
> > +}
> > +
> > +module_init(p9pci_init_module);
> > +module_exit(p9pci_cleanup_module);
> > +
> > +MODULE_DEVICE_TABLE(pci, p9pci_tbl);
> > +MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
> > +MODULE_DESCRIPTION(P9PCI_DRIVER_NAME);
> > +MODULE_LICENSE("GPL");
> > +MODULE_VERSION(P9PCI_DRIVER_VERSION);
>
>
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