This avoids having filp->f_op and the corresponding inode->i_fop different,
which is a little unorthodox.
The ioctl list is split into two: global kvm ioctls and per-vm ioctls. A new
ioctl, KVM_CREATE_VM, is used to create VMs and return the VM fd.
Signed-off-by: Avi Kivity <[email protected]>
---
drivers/kvm/kvm_main.c | 212 ++++++++++++++++++++++++++++++++++++++---------
include/linux/kvm.h | 10 ++-
2 files changed, 180 insertions(+), 42 deletions(-)
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index c01252e..aa07d9c 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -36,6 +36,7 @@
#include <asm/desc.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
+#include <linux/file.h>
#include <linux/fs.h>
#include <linux/mount.h>
@@ -95,6 +96,55 @@ struct segment_descriptor_64 {
#endif
+static struct inode *kvmfs_inode(struct file_operations *fops)
+{
+ int error = -ENOMEM;
+ struct inode *inode = new_inode(kvmfs_mnt->mnt_sb);
+
+ if (!inode)
+ goto eexit_1;
+
+ inode->i_fop = fops;
+
+ /*
+ * Mark the inode dirty from the very beginning,
+ * that way it will never be moved to the dirty
+ * list because mark_inode_dirty() will think
+ * that it already _is_ on the dirty list.
+ */
+ inode->i_state = I_DIRTY;
+ inode->i_mode = S_IRUSR | S_IWUSR;
+ inode->i_uid = current->fsuid;
+ inode->i_gid = current->fsgid;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ return inode;
+
+eexit_1:
+ return ERR_PTR(error);
+}
+
+static struct file *kvmfs_file(struct inode *inode, void *private_data)
+{
+ struct file *file = get_empty_filp();
+
+ if (!file)
+ return ERR_PTR(-ENFILE);
+
+ file->f_path.mnt = mntget(kvmfs_mnt);
+ file->f_path.dentry = d_alloc_anon(inode);
+ if (!file->f_path.dentry)
+ return ERR_PTR(-ENOMEM);
+ file->f_mapping = inode->i_mapping;
+
+ file->f_pos = 0;
+ file->f_flags = O_RDWR;
+ file->f_op = inode->i_fop;
+ file->f_mode = FMODE_READ | FMODE_WRITE;
+ file->f_version = 0;
+ file->private_data = private_data;
+ return file;
+}
+
unsigned long segment_base(u16 selector)
{
struct descriptor_table gdt;
@@ -222,13 +272,13 @@ static void vcpu_put(struct kvm_vcpu *vcpu)
mutex_unlock(&vcpu->mutex);
}
-static int kvm_dev_open(struct inode *inode, struct file *filp)
+static struct kvm *kvm_create_vm(void)
{
struct kvm *kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL);
int i;
if (!kvm)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
spin_lock_init(&kvm->lock);
INIT_LIST_HEAD(&kvm->active_mmu_pages);
@@ -244,7 +294,11 @@ static int kvm_dev_open(struct inode *inode, struct file *filp)
list_add(&kvm->vm_list, &vm_list);
spin_unlock(&kvm_lock);
}
- filp->private_data = kvm;
+ return kvm;
+}
+
+static int kvm_dev_open(struct inode *inode, struct file *filp)
+{
return 0;
}
@@ -300,14 +354,24 @@ static void kvm_free_vcpus(struct kvm *kvm)
static int kvm_dev_release(struct inode *inode, struct file *filp)
{
- struct kvm *kvm = filp->private_data;
+ return 0;
+}
+static void kvm_destroy_vm(struct kvm *kvm)
+{
spin_lock(&kvm_lock);
list_del(&kvm->vm_list);
spin_unlock(&kvm_lock);
kvm_free_vcpus(kvm);
kvm_free_physmem(kvm);
kfree(kvm);
+}
+
+static int kvm_vm_release(struct inode *inode, struct file *filp)
+{
+ struct kvm *kvm = filp->private_data;
+
+ kvm_destroy_vm(kvm);
return 0;
}
@@ -1900,17 +1964,14 @@ static int kvm_dev_ioctl_debug_guest(struct kvm *kvm,
return r;
}
-static long kvm_dev_ioctl(struct file *filp,
- unsigned int ioctl, unsigned long arg)
+static long kvm_vm_ioctl(struct file *filp,
+ unsigned int ioctl, unsigned long arg)
{
struct kvm *kvm = filp->private_data;
void __user *argp = (void __user *)arg;
int r = -EINVAL;
switch (ioctl) {
- case KVM_GET_API_VERSION:
- r = KVM_API_VERSION;
- break;
case KVM_CREATE_VCPU:
r = kvm_dev_ioctl_create_vcpu(kvm, arg);
if (r)
@@ -2052,6 +2113,107 @@ static long kvm_dev_ioctl(struct file *filp,
case KVM_SET_MSRS:
r = msr_io(kvm, argp, do_set_msr, 0);
break;
+ default:
+ ;
+ }
+out:
+ return r;
+}
+
+static struct page *kvm_vm_nopage(struct vm_area_struct *vma,
+ unsigned long address,
+ int *type)
+{
+ struct kvm *kvm = vma->vm_file->private_data;
+ unsigned long pgoff;
+ struct kvm_memory_slot *slot;
+ struct page *page;
+
+ *type = VM_FAULT_MINOR;
+ pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+ slot = gfn_to_memslot(kvm, pgoff);
+ if (!slot)
+ return NOPAGE_SIGBUS;
+ page = gfn_to_page(slot, pgoff);
+ if (!page)
+ return NOPAGE_SIGBUS;
+ get_page(page);
+ return page;
+}
+
+static struct vm_operations_struct kvm_vm_vm_ops = {
+ .nopage = kvm_vm_nopage,
+};
+
+static int kvm_vm_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ vma->vm_ops = &kvm_vm_vm_ops;
+ return 0;
+}
+
+static struct file_operations kvm_vm_fops = {
+ .release = kvm_vm_release,
+ .unlocked_ioctl = kvm_vm_ioctl,
+ .compat_ioctl = kvm_vm_ioctl,
+ .mmap = kvm_vm_mmap,
+};
+
+static int kvm_dev_ioctl_create_vm(void)
+{
+ int fd, r;
+ struct inode *inode;
+ struct file *file;
+ struct kvm *kvm;
+
+ inode = kvmfs_inode(&kvm_vm_fops);
+ if (IS_ERR(inode)) {
+ r = PTR_ERR(inode);
+ goto out1;
+ }
+
+ kvm = kvm_create_vm();
+ if (IS_ERR(kvm)) {
+ r = PTR_ERR(kvm);
+ goto out2;
+ }
+
+ file = kvmfs_file(inode, kvm);
+ if (IS_ERR(file)) {
+ r = PTR_ERR(file);
+ goto out3;
+ }
+
+ r = get_unused_fd();
+ if (r < 0)
+ goto out4;
+ fd = r;
+ fd_install(fd, file);
+
+ return fd;
+
+out4:
+ fput(file);
+out3:
+ kvm_destroy_vm(kvm);
+out2:
+ iput(inode);
+out1:
+ return r;
+}
+
+static long kvm_dev_ioctl(struct file *filp,
+ unsigned int ioctl, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int r = -EINVAL;
+
+ switch (ioctl) {
+ case KVM_GET_API_VERSION:
+ r = KVM_API_VERSION;
+ break;
+ case KVM_CREATE_VM:
+ r = kvm_dev_ioctl_create_vm();
+ break;
case KVM_GET_MSR_INDEX_LIST: {
struct kvm_msr_list __user *user_msr_list = argp;
struct kvm_msr_list msr_list;
@@ -2086,43 +2248,11 @@ out:
return r;
}
-static struct page *kvm_dev_nopage(struct vm_area_struct *vma,
- unsigned long address,
- int *type)
-{
- struct kvm *kvm = vma->vm_file->private_data;
- unsigned long pgoff;
- struct kvm_memory_slot *slot;
- struct page *page;
-
- *type = VM_FAULT_MINOR;
- pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
- slot = gfn_to_memslot(kvm, pgoff);
- if (!slot)
- return NOPAGE_SIGBUS;
- page = gfn_to_page(slot, pgoff);
- if (!page)
- return NOPAGE_SIGBUS;
- get_page(page);
- return page;
-}
-
-static struct vm_operations_struct kvm_dev_vm_ops = {
- .nopage = kvm_dev_nopage,
-};
-
-static int kvm_dev_mmap(struct file *file, struct vm_area_struct *vma)
-{
- vma->vm_ops = &kvm_dev_vm_ops;
- return 0;
-}
-
static struct file_operations kvm_chardev_ops = {
.open = kvm_dev_open,
.release = kvm_dev_release,
.unlocked_ioctl = kvm_dev_ioctl,
.compat_ioctl = kvm_dev_ioctl,
- .mmap = kvm_dev_mmap,
};
static struct miscdevice kvm_dev = {
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index f360459..d6e6635 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -224,7 +224,16 @@ struct kvm_dirty_log {
#define KVMIO 0xAE
+/*
+ * ioctls for /dev/kvm fds:
+ */
#define KVM_GET_API_VERSION _IO(KVMIO, 1)
+#define KVM_CREATE_VM _IO(KVMIO, 2) /* returns a VM fd */
+#define KVM_GET_MSR_INDEX_LIST _IOWR(KVMIO, 15, struct kvm_msr_list)
+
+/*
+ * ioctls for VM fds
+ */
#define KVM_RUN _IOWR(KVMIO, 2, struct kvm_run)
#define KVM_GET_REGS _IOWR(KVMIO, 3, struct kvm_regs)
#define KVM_SET_REGS _IOW(KVMIO, 4, struct kvm_regs)
@@ -238,6 +247,5 @@ struct kvm_dirty_log {
#define KVM_GET_DIRTY_LOG _IOW(KVMIO, 12, struct kvm_dirty_log)
#define KVM_GET_MSRS _IOWR(KVMIO, 13, struct kvm_msrs)
#define KVM_SET_MSRS _IOWR(KVMIO, 14, struct kvm_msrs)
-#define KVM_GET_MSR_INDEX_LIST _IOWR(KVMIO, 15, struct kvm_msr_list)
#endif
-
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