@@ -1099,6 +1099,14 @@ config DEVPORT
depends on ISA || PCI
default y
+config KVM_IVSHMEM
+ tristate "Inter-VM Shared Memory Device"
+ depends on PCI
+ default m
+ help
+ This device maps a region of shared memory between the host OS and any
+ number of virtual machines.
+
source "drivers/s390/char/Kconfig"
endmenu
@@ -111,6 +111,8 @@ obj-$(CONFIG_PS3_FLASH) += ps3flash.o
obj-$(CONFIG_JS_RTC) += js-rtc.o
js-rtc-y = rtc.o
+obj-$(CONFIG_KVM_IVSHMEM) += kvm_ivshmem.o
+
# Files generated that shall be removed upon make clean
clean-files := consolemap_deftbl.c defkeymap.c
new file mode 100644
@@ -0,0 +1,370 @@
+/*
+ * drivers/char/kvm_ivshmem.c - driver for KVM Inter-VM shared memory PCI device
+ *
+ * Copyright 2009 Cam Macdonell <cam@cs.ualberta.ca>
+ *
+ * Based on cirrusfb.c and 8139cp.c:
+ * Copyright 1999-2001 Jeff Garzik
+ * Copyright 2001-2004 Jeff Garzik
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/proc_fs.h>
+#include <linux/smp_lock.h>
+#include <asm/uaccess.h>
+#include <linux/interrupt.h>
+
+#define TRUE 1
+#define FALSE 0
+#define KVM_IVSHMEM_DEVICE_MINOR_NUM 0
+
+enum {
+ /* KVM Shmem device register offsets */
+ IntrMask = 0x00, /* Interrupt Mask */
+ IntrStatus = 0x10, /* Interrupt Status */
+
+ ShmOK = 1 /* Everything is OK */
+};
+
+typedef struct kvm_ivshmem_device {
+ void __iomem * regs;
+
+ void * base_addr;
+
+ unsigned int regaddr;
+ unsigned int reg_size;
+
+ unsigned int ioaddr;
+ unsigned int ioaddr_size;
+ unsigned int irq;
+
+ bool enabled;
+ spinlock_t dev_spinlock;
+} kvm_ivshmem_device;
+
+static kvm_ivshmem_device kvm_ivshmem_dev;
+
+static int device_major_nr;
+
+static int kvm_ivshmem_mmap(struct file *, struct vm_area_struct *);
+static int kvm_ivshmem_open(struct inode *, struct file *);
+static int kvm_ivshmem_release(struct inode *, struct file *);
+static ssize_t kvm_ivshmem_read(struct file *, char *, size_t, loff_t *);
+static ssize_t kvm_ivshmem_write(struct file *, const char *, size_t, loff_t *);
+static loff_t kvm_ivshmem_lseek(struct file * filp, loff_t offset, int origin);
+
+static const struct file_operations kvm_ivshmem_ops = {
+ .owner = THIS_MODULE,
+ .open = kvm_ivshmem_open,
+ .mmap = kvm_ivshmem_mmap,
+ .read = kvm_ivshmem_read,
+ .write = kvm_ivshmem_write,
+ .llseek = kvm_ivshmem_lseek,
+ .release = kvm_ivshmem_release,
+};
+
+static struct pci_device_id kvm_ivshmem_id_table[] = {
+ { 0x1af4, 0x1110, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
+ { 0 },
+};
+MODULE_DEVICE_TABLE (pci, kvm_ivshmem_id_table);
+
+static void kvm_ivshmem_remove_device(struct pci_dev* pdev);
+static int kvm_ivshmem_probe_device (struct pci_dev *pdev,
+ const struct pci_device_id * ent);
+
+static struct pci_driver kvm_ivshmem_pci_driver = {
+ .name = "kvm-shmem",
+ .id_table = kvm_ivshmem_id_table,
+ .probe = kvm_ivshmem_probe_device,
+ .remove = kvm_ivshmem_remove_device,
+};
+
+static ssize_t kvm_ivshmem_read(struct file * filp, char * buffer, size_t len,
+ loff_t * poffset)
+{
+
+ int bytes_read = 0;
+ unsigned long offset;
+
+ offset = *poffset;
+
+ printk(KERN_INFO "kvm_ivshmem: trying to read\n");
+ if (!kvm_ivshmem_dev.base_addr) {
+ printk(KERN_ERR "KVM_IVSHMEM: cannot read from ioaddr (NULL)\n");
+ return 0;
+ }
+
+ if (len > kvm_ivshmem_dev.ioaddr_size - offset) {
+ len = kvm_ivshmem_dev.ioaddr_size - offset;
+ }
+
+ printk(KERN_INFO "KVM_IVSHMEM: len is %u\n", (unsigned) len);
+ if (len == 0) return 0;
+
+ bytes_read = copy_to_user(buffer, kvm_ivshmem_dev.base_addr+offset, len);
+ if (bytes_read > 0) {
+ return -EFAULT;
+ }
+
+ printk(KERN_INFO "KVM_IVSHMEM: read %u bytes at offset %lu\n",
+ (unsigned) len, offset);
+ *poffset += len;
+ return len;
+}
+
+static loff_t kvm_ivshmem_lseek(struct file * filp, loff_t offset, int origin)
+{
+
+ loff_t retval = -1;
+
+ switch (origin) {
+ case 1:
+ offset += filp->f_pos;
+ case 0:
+ retval = offset;
+ if (offset > kvm_ivshmem_dev.ioaddr_size) {
+ offset = kvm_ivshmem_dev.ioaddr_size;
+ }
+ filp->f_pos = offset;
+ }
+
+ return retval;
+}
+
+static ssize_t kvm_ivshmem_write(struct file * filp, const char * buffer,
+ size_t len, loff_t * poffset)
+{
+
+ int bytes_written = 0;
+ unsigned long offset;
+
+ offset = *poffset;
+
+ printk(KERN_INFO "KVM_IVSHMEM: trying to write\n");
+ if (!kvm_ivshmem_dev.base_addr) {
+ printk(KERN_ERR "KVM_IVSHMEM: cannot write to ioaddr (NULL)\n");
+ return 0;
+ }
+
+ if (len > kvm_ivshmem_dev.ioaddr_size - offset) {
+ len = kvm_ivshmem_dev.ioaddr_size - offset;
+ }
+
+ printk(KERN_INFO "KVM_IVSHMEM: len is %u\n", (unsigned) len);
+ if (len == 0) return 0;
+
+ bytes_written = copy_from_user(kvm_ivshmem_dev.base_addr+offset,
+ buffer, len);
+ if (bytes_written > 0) {
+ return -EFAULT;
+ }
+
+ printk(KERN_INFO "KVM_IVSHMEM: wrote %u bytes at offset %lu\n",
+ (unsigned) len, offset);
+ *poffset += len;
+ return len;
+}
+
+static irqreturn_t kvm_ivshmem_interrupt (int irq, void *dev_instance)
+{
+ struct kvm_ivshmem_device * dev = dev_instance;
+ u16 status;
+
+ if (unlikely(dev == NULL))
+ return IRQ_NONE;
+
+ status = readw(dev->regs + IntrStatus);
+ if (!status || (status == 0xFFFF))
+ return IRQ_NONE;
+
+ printk(KERN_INFO "KVM_IVSHMEM: Oops, no interrupts yet (status = 0x%04x)\n",
+ status);
+
+ return IRQ_HANDLED;
+}
+
+static int kvm_ivshmem_probe_device (struct pci_dev *pdev,
+ const struct pci_device_id * ent) {
+
+ int result;
+
+ printk("KVM_IVSHMEM: Probing for KVM_IVSHMEM Device\n");
+
+ result = pci_enable_device(pdev);
+ if (result) {
+ printk(KERN_ERR "Cannot probe KVM_IVSHMEM device %s: error %d\n",
+ pci_name(pdev), result);
+ return result;
+ }
+
+ result = pci_request_regions(pdev, "kvm_ivshmem");
+ if (result < 0) {
+ printk(KERN_ERR "KVM_IVSHMEM: cannot request regions\n");
+ goto pci_disable;
+ } else printk(KERN_ERR "KVM_IVSHMEM: result is %d\n", result);
+
+ kvm_ivshmem_dev.ioaddr = pci_resource_start(pdev, 1);
+ kvm_ivshmem_dev.ioaddr_size = pci_resource_len(pdev, 1);
+
+ kvm_ivshmem_dev.base_addr = pci_iomap(pdev, 1, 0);
+ printk(KERN_INFO "KVM_IVSHMEM: iomap base = 0x%lu \n",
+ (unsigned long) kvm_ivshmem_dev.base_addr);
+
+ if (!kvm_ivshmem_dev.base_addr) {
+ printk(KERN_ERR "KVM_IVSHMEM: cannot iomap region of size %d\n",
+ kvm_ivshmem_dev.ioaddr_size);
+ goto pci_release;
+ }
+
+ printk(KERN_INFO "KVM_IVSHMEM: ioaddr = %x ioaddr_size = %d\n",
+ kvm_ivshmem_dev.ioaddr, kvm_ivshmem_dev.ioaddr_size);
+
+ kvm_ivshmem_dev.regaddr = pci_resource_start(pdev, 0);
+ kvm_ivshmem_dev.reg_size = pci_resource_len(pdev, 0);
+ kvm_ivshmem_dev.regs = pci_iomap(pdev, 0, 0x100);
+
+ if (!kvm_ivshmem_dev.regs) {
+ printk(KERN_ERR "KVM_IVSHMEM: cannot ioremap registers of size %d\n",
+ kvm_ivshmem_dev.reg_size);
+ goto reg_release;
+ }
+
+ printk(KERN_INFO "KVM_IVSHMEM: irq = %u regaddr = %x reg_size = %d\n",
+ pdev->irq, kvm_ivshmem_dev.regaddr, kvm_ivshmem_dev.reg_size);
+
+ if (request_irq(pdev->irq, kvm_ivshmem_interrupt, IRQF_SHARED,
+ "kvm_ivshmem", &kvm_ivshmem_dev)) {
+ printk(KERN_ERR "KVM_IVSHMEM: cannot get interrupt %d\n", pdev->irq);
+ }
+
+ return 0;
+
+
+reg_release:
+ pci_iounmap(pdev, kvm_ivshmem_dev.base_addr);
+pci_release:
+ pci_release_regions(pdev);
+pci_disable:
+ pci_disable_device(pdev);
+ return -EBUSY;
+
+}
+
+static void kvm_ivshmem_remove_device(struct pci_dev* pdev)
+{
+
+ printk(KERN_INFO "Unregister kvm_ivshmem device.\n");
+ free_irq(pdev->irq,&kvm_ivshmem_dev);
+ pci_iounmap(pdev, kvm_ivshmem_dev.regs);
+ pci_iounmap(pdev, kvm_ivshmem_dev.base_addr);
+ pci_release_regions(pdev);
+ pci_disable_device(pdev);
+
+}
+
+static void __exit kvm_ivshmem_cleanup_module (void)
+{
+ pci_unregister_driver (&kvm_ivshmem_pci_driver);
+ unregister_chrdev(device_major_nr, "kvm_ivshmem");
+}
+
+static int __init kvm_ivshmem_init_module (void)
+{
+
+ int err = -ENOMEM;
+
+ /* Register device node ops. */
+ err = register_chrdev(0, "kvm_ivshmem", &kvm_ivshmem_ops);
+ if (err < 0) {
+ printk(KERN_ERR "Unable to register kvm_ivshmem device\n");
+ return err;
+ }
+ device_major_nr = err;
+ printk("KVM_IVSHMEM: Major device number is: %d\n", device_major_nr);
+ kvm_ivshmem_dev.enabled=FALSE;
+
+ err = pci_register_driver(&kvm_ivshmem_pci_driver);
+ if (err < 0) {
+ goto error;
+ }
+
+ return 0;
+
+error:
+ unregister_chrdev(device_major_nr, "kvm_ivshmem");
+ return err;
+}
+
+
+static int kvm_ivshmem_open(struct inode * inode, struct file * filp)
+{
+
+ printk(KERN_INFO "Opening kvm_ivshmem device\n");
+
+ if (MINOR(inode->i_rdev) != KVM_IVSHMEM_DEVICE_MINOR_NUM) {
+ printk(KERN_INFO "minor number is %d\n", KVM_IVSHMEM_DEVICE_MINOR_NUM);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static int kvm_ivshmem_release(struct inode * inode, struct file * filp)
+{
+
+ return 0;
+}
+
+static int kvm_ivshmem_mmap(struct file *filp, struct vm_area_struct * vma)
+{
+
+ unsigned long len;
+ unsigned long off;
+ unsigned long start;
+
+ lock_kernel();
+
+ off = vma->vm_pgoff << PAGE_SHIFT;
+ start = kvm_ivshmem_dev.ioaddr;
+
+ len=PAGE_ALIGN((start & ~PAGE_MASK) + kvm_ivshmem_dev.ioaddr_size);
+ start &= PAGE_MASK;
+
+ printk(KERN_INFO "%lu - %lu + %lu\n",vma->vm_end ,vma->vm_start, off);
+ printk(KERN_INFO "%lu > %lu\n",(vma->vm_end - vma->vm_start + off), len);
+
+ if ((vma->vm_end - vma->vm_start + off) > len) {
+ unlock_kernel();
+ return -EINVAL;
+ }
+
+ off += start;
+ vma->vm_pgoff = off >> PAGE_SHIFT;
+
+ vma->vm_flags |= VM_SHARED|VM_RESERVED;
+
+ if(io_remap_pfn_range(vma, vma->vm_start,
+ off >> PAGE_SHIFT, vma->vm_end - vma->vm_start,
+ vma->vm_page_prot))
+ {
+ printk("mmap failed\n");
+ unlock_kernel();
+ return -ENXIO;
+ }
+ unlock_kernel();
+
+ return 0;
+}
+
+module_init(kvm_ivshmem_init_module);
+module_exit(kvm_ivshmem_cleanup_module);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Cam Macdonell <cam@cs.ualberta.ca>");
+MODULE_DESCRIPTION("KVM inter-VM shared memory module");
+MODULE_VERSION("1.0");
This driver corresponds to the shared memory PCI device that maps a host file into shared memory on the device. Accessing the device can be done through creating a device file on the guest num =`cat /proc/devices | grep kvm_ivshmem | awk '{print $1}` mknod --mode=666 /dev/ivshmem $num 0 read, write, lseek and mmap are supported, but mmap is the usual usage to get zero-copy communication. The driver contains the initial interrupt support, but I have not yet added the unix domain socket to support interrupts yet. --- drivers/char/Kconfig | 8 + drivers/char/Makefile | 2 + drivers/char/kvm_ivshmem.c | 370 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 380 insertions(+), 0 deletions(-) create mode 100644 drivers/char/kvm_ivshmem.c