x86/lguest: Remove lguest support

Lguest seems to be rather unused these days. It has seen only patches
ensuring it still builds the last two years and its official state is
"Odd Fixes".

Remove it in order to be able to clean up the paravirt code.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: boris.ostrovsky@oracle.com
Cc: lguest@lists.ozlabs.org
Cc: rusty@rustcorp.com.au
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20170816173157.8633-3-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 0 insertions, 398 deletions

diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
deleted file mode 100644
index 395ed1961dbf..000000000000
--- a/drivers/lguest/core.c
+++ /dev/null
@@ -1,398 +0,0 @@
-/*P:400
- * This contains run_guest() which actually calls into the Host<->Guest
- * Switcher and analyzes the return, such as determining if the Guest wants the
- * Host to do something.  This file also contains useful helper routines.
-:*/
-#include <linux/module.h>
-#include <linux/stringify.h>
-#include <linux/stddef.h>
-#include <linux/io.h>
-#include <linux/mm.h>
-#include <linux/sched/signal.h>
-#include <linux/vmalloc.h>
-#include <linux/cpu.h>
-#include <linux/freezer.h>
-#include <linux/highmem.h>
-#include <linux/slab.h>
-#include <asm/paravirt.h>
-#include <asm/pgtable.h>
-#include <linux/uaccess.h>
-#include <asm/poll.h>
-#include <asm/asm-offsets.h>
-#include "lg.h"
-
-unsigned long switcher_addr;
-struct page **lg_switcher_pages;
-static struct vm_struct *switcher_text_vma;
-static struct vm_struct *switcher_stacks_vma;
-
-/* This One Big lock protects all inter-guest data structures. */
-DEFINE_MUTEX(lguest_lock);
-
-/*H:010
- * We need to set up the Switcher at a high virtual address.  Remember the
- * Switcher is a few hundred bytes of assembler code which actually changes the
- * CPU to run the Guest, and then changes back to the Host when a trap or
- * interrupt happens.
- *
- * The Switcher code must be at the same virtual address in the Guest as the
- * Host since it will be running as the switchover occurs.
- *
- * Trying to map memory at a particular address is an unusual thing to do, so
- * it's not a simple one-liner.
- */
-static __init int map_switcher(void)
-{
-	int i, err;
-
-	/*
-	 * Map the Switcher in to high memory.
-	 *
-	 * It turns out that if we choose the address 0xFFC00000 (4MB under the
-	 * top virtual address), it makes setting up the page tables really
-	 * easy.
-	 */
-
-	/* We assume Switcher text fits into a single page. */
-	if (end_switcher_text - start_switcher_text > PAGE_SIZE) {
-		printk(KERN_ERR "lguest: switcher text too large (%zu)\n",
-		       end_switcher_text - start_switcher_text);
-		return -EINVAL;
-	}
-
-	/*
-	 * We allocate an array of struct page pointers.  map_vm_area() wants
-	 * this, rather than just an array of pages.
-	 */
-	lg_switcher_pages = kmalloc(sizeof(lg_switcher_pages[0])
-				    * TOTAL_SWITCHER_PAGES,
-				    GFP_KERNEL);
-	if (!lg_switcher_pages) {
-		err = -ENOMEM;
-		goto out;
-	}
-
-	/*
-	 * Now we actually allocate the pages.  The Guest will see these pages,
-	 * so we make sure they're zeroed.
-	 */
-	for (i = 0; i < TOTAL_SWITCHER_PAGES; i++) {
-		lg_switcher_pages[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
-		if (!lg_switcher_pages[i]) {
-			err = -ENOMEM;
-			goto free_some_pages;
-		}
-	}
-
-	/*
-	 * Copy in the compiled-in Switcher code (from x86/switcher_32.S).
-	 * It goes in the first page, which we map in momentarily.
-	 */
-	memcpy(kmap(lg_switcher_pages[0]), start_switcher_text,
-	       end_switcher_text - start_switcher_text);
-	kunmap(lg_switcher_pages[0]);
-
-	/*
-	 * We place the Switcher underneath the fixmap area, which is the
-	 * highest virtual address we can get.  This is important, since we
-	 * tell the Guest it can't access this memory, so we want its ceiling
-	 * as high as possible.
-	 */
-	switcher_addr = FIXADDR_START - TOTAL_SWITCHER_PAGES*PAGE_SIZE;
-
-	/*
-	 * Now we reserve the "virtual memory area"s we want.  We might
-	 * not get them in theory, but in practice it's worked so far.
-	 *
-	 * We want the switcher text to be read-only and executable, and
-	 * the stacks to be read-write and non-executable.
-	 */
-	switcher_text_vma = __get_vm_area(PAGE_SIZE, VM_ALLOC|VM_NO_GUARD,
-					  switcher_addr,
-					  switcher_addr + PAGE_SIZE);
-
-	if (!switcher_text_vma) {
-		err = -ENOMEM;
-		printk("lguest: could not map switcher pages high\n");
-		goto free_pages;
-	}
-
-	switcher_stacks_vma = __get_vm_area(SWITCHER_STACK_PAGES * PAGE_SIZE,
-					    VM_ALLOC|VM_NO_GUARD,
-					    switcher_addr + PAGE_SIZE,
-					    switcher_addr + TOTAL_SWITCHER_PAGES * PAGE_SIZE);
-	if (!switcher_stacks_vma) {
-		err = -ENOMEM;
-		printk("lguest: could not map switcher pages high\n");
-		goto free_text_vma;
-	}
-
-	/*
-	 * This code actually sets up the pages we've allocated to appear at
-	 * switcher_addr.  map_vm_area() takes the vma we allocated above, the
-	 * kind of pages we're mapping (kernel text pages and kernel writable
-	 * pages respectively), and a pointer to our array of struct pages.
-	 */
-	err = map_vm_area(switcher_text_vma, PAGE_KERNEL_RX, lg_switcher_pages);
-	if (err) {
-		printk("lguest: text map_vm_area failed: %i\n", err);
-		goto free_vmas;
-	}
-
-	err = map_vm_area(switcher_stacks_vma, PAGE_KERNEL,
-			  lg_switcher_pages + SWITCHER_TEXT_PAGES);
-	if (err) {
-		printk("lguest: stacks map_vm_area failed: %i\n", err);
-		goto free_vmas;
-	}
-
-	/*
-	 * Now the Switcher is mapped at the right address, we can't fail!
-	 */
-	printk(KERN_INFO "lguest: mapped switcher at %p\n",
-	       switcher_text_vma->addr);
-	/* And we succeeded... */
-	return 0;
-
-free_vmas:
-	/* Undoes map_vm_area and __get_vm_area */
-	vunmap(switcher_stacks_vma->addr);
-free_text_vma:
-	vunmap(switcher_text_vma->addr);
-free_pages:
-	i = TOTAL_SWITCHER_PAGES;
-free_some_pages:
-	for (--i; i >= 0; i--)
-		__free_pages(lg_switcher_pages[i], 0);
-	kfree(lg_switcher_pages);
-out:
-	return err;
-}
-/*:*/
-
-/* Cleaning up the mapping when the module is unloaded is almost... too easy. */
-static void unmap_switcher(void)
-{
-	unsigned int i;
-
-	/* vunmap() undoes *both* map_vm_area() and __get_vm_area(). */
-	vunmap(switcher_text_vma->addr);
-	vunmap(switcher_stacks_vma->addr);
-	/* Now we just need to free the pages we copied the switcher into */
-	for (i = 0; i < TOTAL_SWITCHER_PAGES; i++)
-		__free_pages(lg_switcher_pages[i], 0);
-	kfree(lg_switcher_pages);
-}
-
-/*H:032
- * Dealing With Guest Memory.
- *
- * Before we go too much further into the Host, we need to grok the routines
- * we use to deal with Guest memory.
- *
- * When the Guest gives us (what it thinks is) a physical address, we can use
- * the normal copy_from_user() & copy_to_user() on the corresponding place in
- * the memory region allocated by the Launcher.
- *
- * But we can't trust the Guest: it might be trying to access the Launcher
- * code.  We have to check that the range is below the pfn_limit the Launcher
- * gave us.  We have to make sure that addr + len doesn't give us a false
- * positive by overflowing, too.
- */
-bool lguest_address_ok(const struct lguest *lg,
-		       unsigned long addr, unsigned long len)
-{
-	return addr+len <= lg->pfn_limit * PAGE_SIZE && (addr+len >= addr);
-}
-
-/*
- * This routine copies memory from the Guest.  Here we can see how useful the
- * kill_lguest() routine we met in the Launcher can be: we return a random
- * value (all zeroes) instead of needing to return an error.
- */
-void __lgread(struct lg_cpu *cpu, void *b, unsigned long addr, unsigned bytes)
-{
-	if (!lguest_address_ok(cpu->lg, addr, bytes)
-	    || copy_from_user(b, cpu->lg->mem_base + addr, bytes) != 0) {
-		/* copy_from_user should do this, but as we rely on it... */
-		memset(b, 0, bytes);
-		kill_guest(cpu, "bad read address %#lx len %u", addr, bytes);
-	}
-}
-
-/* This is the write (copy into Guest) version. */
-void __lgwrite(struct lg_cpu *cpu, unsigned long addr, const void *b,
-	       unsigned bytes)
-{
-	if (!lguest_address_ok(cpu->lg, addr, bytes)
-	    || copy_to_user(cpu->lg->mem_base + addr, b, bytes) != 0)
-		kill_guest(cpu, "bad write address %#lx len %u", addr, bytes);
-}
-/*:*/
-
-/*H:030
- * Let's jump straight to the the main loop which runs the Guest.
- * Remember, this is called by the Launcher reading /dev/lguest, and we keep
- * going around and around until something interesting happens.
- */
-int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
-{
-	/* If the launcher asked for a register with LHREQ_GETREG */
-	if (cpu->reg_read) {
-		if (put_user(*cpu->reg_read, user))
-			return -EFAULT;
-		cpu->reg_read = NULL;
-		return sizeof(*cpu->reg_read);
-	}
-
-	/* We stop running once the Guest is dead. */
-	while (!cpu->lg->dead) {
-		unsigned int irq;
-		bool more;
-
-		/* First we run any hypercalls the Guest wants done. */
-		if (cpu->hcall)
-			do_hypercalls(cpu);
-
-		/* Do we have to tell the Launcher about a trap? */
-		if (cpu->pending.trap) {
-			if (copy_to_user(user, &cpu->pending,
-					 sizeof(cpu->pending)))
-				return -EFAULT;
-			return sizeof(cpu->pending);
-		}
-
-		/*
-		 * All long-lived kernel loops need to check with this horrible
-		 * thing called the freezer.  If the Host is trying to suspend,
-		 * it stops us.
-		 */
-		try_to_freeze();
-
-		/* Check for signals */
-		if (signal_pending(current))
-			return -ERESTARTSYS;
-
-		/*
-		 * Check if there are any interrupts which can be delivered now:
-		 * if so, this sets up the hander to be executed when we next
-		 * run the Guest.
-		 */
-		irq = interrupt_pending(cpu, &more);
-		if (irq < LGUEST_IRQS)
-			try_deliver_interrupt(cpu, irq, more);
-
-		/*
-		 * Just make absolutely sure the Guest is still alive.  One of
-		 * those hypercalls could have been fatal, for example.
-		 */
-		if (cpu->lg->dead)
-			break;
-
-		/*
-		 * If the Guest asked to be stopped, we sleep.  The Guest's
-		 * clock timer will wake us.
-		 */
-		if (cpu->halted) {
-			set_current_state(TASK_INTERRUPTIBLE);
-			/*
-			 * Just before we sleep, make sure no interrupt snuck in
-			 * which we should be doing.
-			 */
-			if (interrupt_pending(cpu, &more) < LGUEST_IRQS)
-				set_current_state(TASK_RUNNING);
-			else
-				schedule();
-			continue;
-		}
-
-		/*
-		 * OK, now we're ready to jump into the Guest.  First we put up
-		 * the "Do Not Disturb" sign:
-		 */
-		local_irq_disable();
-
-		/* Actually run the Guest until something happens. */
-		lguest_arch_run_guest(cpu);
-
-		/* Now we're ready to be interrupted or moved to other CPUs */
-		local_irq_enable();
-
-		/* Now we deal with whatever happened to the Guest. */
-		lguest_arch_handle_trap(cpu);
-	}
-
-	/* Special case: Guest is 'dead' but wants a reboot. */
-	if (cpu->lg->dead == ERR_PTR(-ERESTART))
-		return -ERESTART;
-
-	/* The Guest is dead => "No such file or directory" */
-	return -ENOENT;
-}
-
-/*H:000
- * Welcome to the Host!
- *
- * By this point your brain has been tickled by the Guest code and numbed by
- * the Launcher code; prepare for it to be stretched by the Host code.  This is
- * the heart.  Let's begin at the initialization routine for the Host's lg
- * module.
- */
-static int __init init(void)
-{
-	int err;
-
-	/* Lguest can't run under Xen, VMI or itself.  It does Tricky Stuff. */
-	if (get_kernel_rpl() != 0) {
-		printk("lguest is afraid of being a guest\n");
-		return -EPERM;
-	}
-
-	/* First we put the Switcher up in very high virtual memory. */
-	err = map_switcher();
-	if (err)
-		goto out;
-
-	/* We might need to reserve an interrupt vector. */
-	err = init_interrupts();
-	if (err)
-		goto unmap;
-
-	/* /dev/lguest needs to be registered. */
-	err = lguest_device_init();
-	if (err)
-		goto free_interrupts;
-
-	/* Finally we do some architecture-specific setup. */
-	lguest_arch_host_init();
-
-	/* All good! */
-	return 0;
-
-free_interrupts:
-	free_interrupts();
-unmap:
-	unmap_switcher();
-out:
-	return err;
-}
-
-/* Cleaning up is just the same code, backwards.  With a little French. */
-static void __exit fini(void)
-{
-	lguest_device_remove();
-	free_interrupts();
-	unmap_switcher();
-
-	lguest_arch_host_fini();
-}
-/*:*/
-
-/*
- * The Host side of lguest can be a module.  This is a nice way for people to
- * play with it.
- */
-module_init(init);
-module_exit(fini);
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");