diff options
Diffstat (limited to 'drivers/lguest/lguest_user.c')
| -rw-r--r-- | drivers/lguest/lguest_user.c | 138 |
1 files changed, 33 insertions, 105 deletions
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c index 80d1b58c769..ee405b38383 100644 --- a/drivers/lguest/lguest_user.c +++ b/drivers/lguest/lguest_user.c @@ -1,73 +1,17 @@ /*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) +static int break_guest_out(struct lguest *lg, const unsigned long __user *input) { unsigned long on; @@ -90,9 +34,9 @@ static int break_guest_out(struct lguest *lg, const u32 __user *input) /*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; @@ -133,17 +77,19 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) 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 @@ -153,23 +99,17 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) * 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) { @@ -182,20 +122,15 @@ static int initialize(struct file *file, const u32 __user *input) 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. */ @@ -210,17 +145,13 @@ static int initialize(struct file *file, const u32 __user *input) /* 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); @@ -260,18 +191,19 @@ unlock: /*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 * 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) @@ -287,13 +219,11 @@ static ssize_t write(struct file *file, const char __user *input, 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; } @@ -319,8 +249,6 @@ static int close(struct inode *inode, struct file *file) 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 |