My current view of the IO stack is the following:
-------------- -------------- ------------ ----------
---------- ---------
|NET_PCI_BACK| |BLK_PCI_BACK| |9P_PCI_BACK| |NET_FRONT|
|BLK_FRONT| |9P_FRONT|
-------------- -------------- ------------ ----------
---------- ---------
------------- ---------------
-------------------
|KVM_PCI_BUS| |hypercall_ops|
|shared_mem_virtio|
------------- ---------------
-------------------
So the 9P implementation should add the front end logic and the
p9_pci_backend that glues the shared_memory, pci_bus and hypercalls
together.
>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 <[email protected]> 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 <[email protected]>
>> >
>> > This adds a shared memory transport for a synthetic 9p device for
>> > paravirtualized file system support under KVM/QEMU.
>> >
>> > Signed-off-by: Latchesar Ionkov <[email protected]>
>> > Signed-off-by: Eric Van Hensbergen <[email protected]>
>> > ---
>> > 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 <[email protected]>
>> > + *
>> > + * 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 <[email protected]>");
>> > +MODULE_DESCRIPTION(P9PCI_DRIVER_NAME);
>> > +MODULE_LICENSE("GPL");
>> > +MODULE_VERSION(P9PCI_DRIVER_VERSION);
>>
>>
>>
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>---
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