/*P:200 This contains all the /dev/lguest code, whereby the userspace launcher
* controls and communicates with the Guest. For example, the first write will
- * tell us the memory size, pagetable, entry point and kernel address offset.
- * A read will run the Guest until a signal is pending (-EINTR), or the Guest
- * does a DMA out to the Launcher. Writes are also used to get a DMA buffer
- * registered by the Guest and to send the Guest an interrupt. :*/
+ * tell us the Guest's memory layout, pagetable, entry point and kernel address
+ * offset. A read will run the Guest until something happens, such as a signal
+ * or the Guest doing a NOTIFY out to the Launcher. :*/
#include <linux/uaccess.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include "lg.h"
-/*L:030 setup_regs() doesn't really belong in this file, but it gives us an
- * early glimpse deeper into the Host so it's worth having here.
- *
- * Most of the Guest's registers are left alone: we used get_zeroed_page() to
- * allocate the structure, so they will be 0. */
-static void setup_regs(struct lguest_regs *regs, unsigned long start)
-{
- /* There are four "segment" registers which the Guest needs to boot:
- * The "code segment" register (cs) refers to the kernel code segment
- * __KERNEL_CS, and the "data", "extra" and "stack" segment registers
- * refer to the kernel data segment __KERNEL_DS.
- *
- * The privilege level is packed into the lower bits. The Guest runs
- * at privilege level 1 (GUEST_PL).*/
- regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL;
- regs->cs = __KERNEL_CS|GUEST_PL;
-
- /* The "eflags" register contains miscellaneous flags. Bit 1 (0x002)
- * is supposed to always be "1". Bit 9 (0x200) controls whether
- * interrupts are enabled. We always leave interrupts enabled while
- * running the Guest. */
- regs->eflags = 0x202;
-
- /* The "Extended Instruction Pointer" register says where the Guest is
- * running. */
- regs->eip = start;
-
- /* %esi points to our boot information, at physical address 0, so don't
- * touch it. */
-}
-
-/*L:310 To send DMA into the Guest, the Launcher needs to be able to ask for a
- * DMA buffer. This is done by writing LHREQ_GETDMA and the key to
- * /dev/lguest. */
-static long user_get_dma(struct lguest *lg, const u32 __user *input)
-{
- unsigned long key, udma, irq;
-
- /* Fetch the key they wrote to us. */
- if (get_user(key, input) != 0)
- return -EFAULT;
- /* Look for a free Guest DMA buffer bound to that key. */
- udma = get_dma_buffer(lg, key, &irq);
- if (!udma)
- return -ENOENT;
-
- /* We need to tell the Launcher what interrupt the Guest expects after
- * the buffer is filled. We stash it in udma->used_len. */
- lgwrite_u32(lg, udma + offsetof(struct lguest_dma, used_len), irq);
-
- /* The (guest-physical) address of the DMA buffer is returned from
- * the write(). */
- return udma;
-}
-
-/*L:315 To force the Guest to stop running and return to the Launcher, the
- * Waker sets writes LHREQ_BREAK and the value "1" to /dev/lguest. The
- * Launcher then writes LHREQ_BREAK and "0" to release the Waker. */
-static int break_guest_out(struct lguest *lg, const u32 __user *input)
+/*L:055 When something happens, the Waker process needs a way to stop the
+ * kernel running the Guest and return to the Launcher. So the Waker writes
+ * LHREQ_BREAK and the value "1" to /dev/lguest to do this. Once the Launcher
+ * has done whatever needs attention, it writes LHREQ_BREAK and "0" to release
+ * the Waker. */
+static int break_guest_out(struct lguest *lg, const unsigned long __user *input)
{
unsigned long on;
- /* Fetch whether they're turning break on or off.. */
+ /* Fetch whether they're turning break on or off. */
if (get_user(on, input) != 0)
return -EFAULT;
if (on) {
lg->break_out = 1;
- /* Pop it out (may be running on different CPU) */
+ /* Pop it out of the Guest (may be running on different CPU) */
wake_up_process(lg->tsk);
/* Wait for them to reset it */
return wait_event_interruptible(lg->break_wq, !lg->break_out);
/*L:050 Sending an interrupt is done by writing LHREQ_IRQ and an interrupt
* number to /dev/lguest. */
-static int user_send_irq(struct lguest *lg, const u32 __user *input)
+static int user_send_irq(struct lguest *lg, const unsigned long __user *input)
{
- u32 irq;
+ unsigned long irq;
if (get_user(irq, input) != 0)
return -EFAULT;
if (!lg)
return -EINVAL;
- /* If you're not the task which owns the guest, go away. */
+ /* If you're not the task which owns the Guest, go away. */
if (current != lg->tsk)
return -EPERM;
return len;
}
- /* If we returned from read() last time because the Guest sent DMA,
+ /* If we returned from read() last time because the Guest notified,
* clear the flag. */
- if (lg->dma_is_pending)
- lg->dma_is_pending = 0;
+ if (lg->pending_notify)
+ lg->pending_notify = 0;
/* Run the Guest until something interesting happens. */
return run_guest(lg, (unsigned long __user *)user);
}
-/*L:020 The initialization write supplies 4 32-bit values (in addition to the
- * 32-bit LHREQ_INITIALIZE value). These are:
+/*L:020 The initialization write supplies 4 pointer sized (32 or 64 bit)
+ * values (in addition to the LHREQ_INITIALIZE value). These are:
+ *
+ * base: The start of the Guest-physical memory inside the Launcher memory.
*
* pfnlimit: The highest (Guest-physical) page number the Guest should be
- * allowed to access. The Launcher has to live in Guest memory, so it sets
- * this to ensure the Guest can't reach it.
+ * allowed to access. The Guest memory lives inside the Launcher, so it sets
+ * this to ensure the Guest can only reach its own memory.
*
* pgdir: The (Guest-physical) address of the top of the initial Guest
* pagetables (which are set up by the Launcher).
*
* start: The first instruction to execute ("eip" in x86-speak).
- *
- * page_offset: The PAGE_OFFSET constant in the Guest kernel. We should
- * probably wean the code off this, but it's a very useful constant! Any
- * address above this is within the Guest kernel, and any kernel address can
- * quickly converted from physical to virtual by adding PAGE_OFFSET. It's
- * 0xC0000000 (3G) by default, but it's configurable at kernel build time.
*/
-static int initialize(struct file *file, const u32 __user *input)
+static int initialize(struct file *file, const unsigned long __user *input)
{
/* "struct lguest" contains everything we (the Host) know about a
* Guest. */
struct lguest *lg;
- int err, i;
- u32 args[4];
+ int err;
+ unsigned long args[4];
- /* We grab the Big Lguest lock, which protects the global array
- * "lguests" and multiple simultaneous initializations. */
+ /* We grab the Big Lguest lock, which protects against multiple
+ * simultaneous initializations. */
mutex_lock(&lguest_lock);
/* You can't initialize twice! Close the device and start again... */
if (file->private_data) {
goto unlock;
}
- /* Find an unused guest. */
- i = find_free_guest();
- if (i < 0) {
- err = -ENOSPC;
+ lg = kzalloc(sizeof(*lg), GFP_KERNEL);
+ if (!lg) {
+ err = -ENOMEM;
goto unlock;
}
- /* OK, we have an index into the "lguest" array: "lg" is a convenient
- * pointer. */
- lg = &lguests[i];
/* Populate the easy fields of our "struct lguest" */
- lg->guestid = i;
- lg->pfn_limit = args[0];
- lg->page_offset = args[3];
+ lg->mem_base = (void __user *)(long)args[0];
+ lg->pfn_limit = args[1];
/* We need a complete page for the Guest registers: they are accessible
* to the Guest and we can only grant it access to whole pages. */
/* Initialize the Guest's shadow page tables, using the toplevel
* address the Launcher gave us. This allocates memory, so can
* fail. */
- err = init_guest_pagetable(lg, args[1]);
+ err = init_guest_pagetable(lg, args[2]);
if (err)
goto free_regs;
/* Now we initialize the Guest's registers, handing it the start
* address. */
- setup_regs(lg->regs, args[2]);
-
- /* There are a couple of GDT entries the Guest expects when first
- * booting. */
- setup_guest_gdt(lg);
+ lguest_arch_setup_regs(lg, args[3]);
/* The timer for lguest's clock needs initialization. */
init_clockdev(lg);
}
/*L:010 The first operation the Launcher does must be a write. All writes
- * start with a 32 bit number: for the first write this must be
+ * start with an unsigned long number: for the first write this must be
* LHREQ_INITIALIZE to set up the Guest. After that the Launcher can use
- * writes of other values to get DMA buffers and send interrupts. */
-static ssize_t write(struct file *file, const char __user *input,
+ * writes of other values to send interrupts. */
+static ssize_t write(struct file *file, const char __user *in,
size_t size, loff_t *off)
{
/* Once the guest is initialized, we hold the "struct lguest" in the
* file private data. */
struct lguest *lg = file->private_data;
- u32 req;
+ const unsigned long __user *input = (const unsigned long __user *)in;
+ unsigned long req;
if (get_user(req, input) != 0)
return -EFAULT;
- input += sizeof(req);
+ input++;
/* If you haven't initialized, you must do that first. */
if (req != LHREQ_INITIALIZE && !lg)
switch (req) {
case LHREQ_INITIALIZE:
- return initialize(file, (const u32 __user *)input);
- case LHREQ_GETDMA:
- return user_get_dma(lg, (const u32 __user *)input);
+ return initialize(file, input);
case LHREQ_IRQ:
- return user_send_irq(lg, (const u32 __user *)input);
+ return user_send_irq(lg, input);
case LHREQ_BREAK:
- return break_guest_out(lg, (const u32 __user *)input);
+ return break_guest_out(lg, input);
default:
return -EINVAL;
}
mutex_lock(&lguest_lock);
/* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */
hrtimer_cancel(&lg->hrt);
- /* Free any DMA buffers the Guest had bound. */
- release_all_dma(lg);
/* Free up the shadow page tables for the Guest. */
free_guest_pagetable(lg);
/* Now all the memory cleanups are done, it's safe to release the
* The Launcher is the Host userspace program which sets up, runs and services
* the Guest. In fact, many comments in the Drivers which refer to "the Host"
* doing things are inaccurate: the Launcher does all the device handling for
- * the Guest. The Guest can't tell what's done by the the Launcher and what by
- * the Host.
+ * the Guest, but the Guest can't know that.
*
* Just to confuse you: to the Host kernel, the Launcher *is* the Guest and we
* shall see more of that later.
git.samba.org / sfrench / cifs-2.6.git / blobdiff