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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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