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6c8dca5d53
A non-periodic clock_event_device and the "jiffies" clock don't mix well: tick_handle_periodic() can go into an infinite loop. Currently lguest guests use the jiffies clock when the TSC is unusable. Instead, make the Host write the current time into the lguest page on every interrupt. This doesn't cost much but is more precise and at least as accurate as the jiffies clock. It also gets rid of the GET_WALLCLOCK hypercall. Also, delay setting sched_clock until our clock is set up, otherwise the early printk timestamps can go backwards (not harmful, just ugly). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
301 lines
9.5 KiB
C
301 lines
9.5 KiB
C
#ifndef _LGUEST_H
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#define _LGUEST_H
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#include <asm/desc.h>
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#define GDT_ENTRY_LGUEST_CS 10
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#define GDT_ENTRY_LGUEST_DS 11
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#define LGUEST_CS (GDT_ENTRY_LGUEST_CS * 8)
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#define LGUEST_DS (GDT_ENTRY_LGUEST_DS * 8)
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/stringify.h>
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#include <linux/binfmts.h>
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#include <linux/futex.h>
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#include <linux/lguest.h>
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#include <linux/lguest_launcher.h>
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#include <linux/wait.h>
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#include <linux/err.h>
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#include <asm/semaphore.h>
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#include "irq_vectors.h"
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#define GUEST_PL 1
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struct lguest_regs
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{
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/* Manually saved part. */
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unsigned long ebx, ecx, edx;
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unsigned long esi, edi, ebp;
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unsigned long gs;
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unsigned long eax;
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unsigned long fs, ds, es;
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unsigned long trapnum, errcode;
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/* Trap pushed part */
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unsigned long eip;
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unsigned long cs;
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unsigned long eflags;
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unsigned long esp;
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unsigned long ss;
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};
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void free_pagetables(void);
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int init_pagetables(struct page **switcher_page, unsigned int pages);
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/* Full 4G segment descriptors, suitable for CS and DS. */
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#define FULL_EXEC_SEGMENT ((struct desc_struct){0x0000ffff, 0x00cf9b00})
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#define FULL_SEGMENT ((struct desc_struct){0x0000ffff, 0x00cf9300})
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struct lguest_dma_info
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{
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struct list_head list;
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union futex_key key;
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unsigned long dmas;
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u16 next_dma;
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u16 num_dmas;
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u16 guestid;
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u8 interrupt; /* 0 when not registered */
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};
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/*H:310 The page-table code owes a great debt of gratitude to Andi Kleen. He
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* reviewed the original code which used "u32" for all page table entries, and
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* insisted that it would be far clearer with explicit typing. I thought it
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* was overkill, but he was right: it is much clearer than it was before.
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*
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* We have separate types for the Guest's ptes & pgds and the shadow ptes &
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* pgds. There's already a Linux type for these (pte_t and pgd_t) but they
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* change depending on kernel config options (PAE). */
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/* Each entry is identical: lower 12 bits of flags and upper 20 bits for the
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* "page frame number" (0 == first physical page, etc). They are different
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* types so the compiler will warn us if we mix them improperly. */
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typedef union {
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struct { unsigned flags:12, pfn:20; };
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struct { unsigned long val; } raw;
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} spgd_t;
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typedef union {
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struct { unsigned flags:12, pfn:20; };
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struct { unsigned long val; } raw;
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} spte_t;
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typedef union {
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struct { unsigned flags:12, pfn:20; };
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struct { unsigned long val; } raw;
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} gpgd_t;
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typedef union {
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struct { unsigned flags:12, pfn:20; };
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struct { unsigned long val; } raw;
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} gpte_t;
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/* We have two convenient macros to convert a "raw" value as handed to us by
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* the Guest into the correct Guest PGD or PTE type. */
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#define mkgpte(_val) ((gpte_t){.raw.val = _val})
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#define mkgpgd(_val) ((gpgd_t){.raw.val = _val})
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/*:*/
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struct pgdir
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{
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unsigned long cr3;
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spgd_t *pgdir;
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};
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/* This is a guest-specific page (mapped ro) into the guest. */
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struct lguest_ro_state
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{
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/* Host information we need to restore when we switch back. */
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u32 host_cr3;
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struct Xgt_desc_struct host_idt_desc;
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struct Xgt_desc_struct host_gdt_desc;
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u32 host_sp;
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/* Fields which are used when guest is running. */
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struct Xgt_desc_struct guest_idt_desc;
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struct Xgt_desc_struct guest_gdt_desc;
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struct i386_hw_tss guest_tss;
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struct desc_struct guest_idt[IDT_ENTRIES];
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struct desc_struct guest_gdt[GDT_ENTRIES];
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};
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/* We have two pages shared with guests, per cpu. */
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struct lguest_pages
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{
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/* This is the stack page mapped rw in guest */
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char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
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struct lguest_regs regs;
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/* This is the host state & guest descriptor page, ro in guest */
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struct lguest_ro_state state;
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} __attribute__((aligned(PAGE_SIZE)));
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#define CHANGED_IDT 1
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#define CHANGED_GDT 2
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#define CHANGED_GDT_TLS 4 /* Actually a subset of CHANGED_GDT */
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#define CHANGED_ALL 3
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/* The private info the thread maintains about the guest. */
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struct lguest
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{
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/* At end of a page shared mapped over lguest_pages in guest. */
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unsigned long regs_page;
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struct lguest_regs *regs;
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struct lguest_data __user *lguest_data;
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struct task_struct *tsk;
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struct mm_struct *mm; /* == tsk->mm, but that becomes NULL on exit */
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u16 guestid;
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u32 pfn_limit;
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u32 page_offset;
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u32 cr2;
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int halted;
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int ts;
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u32 next_hcall;
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u32 esp1;
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u8 ss1;
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/* Do we need to stop what we're doing and return to userspace? */
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int break_out;
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wait_queue_head_t break_wq;
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/* Bitmap of what has changed: see CHANGED_* above. */
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int changed;
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struct lguest_pages *last_pages;
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/* We keep a small number of these. */
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u32 pgdidx;
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struct pgdir pgdirs[4];
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/* Cached wakeup: we hold a reference to this task. */
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struct task_struct *wake;
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unsigned long noirq_start, noirq_end;
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int dma_is_pending;
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unsigned long pending_dma; /* struct lguest_dma */
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unsigned long pending_key; /* address they're sending to */
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unsigned int stack_pages;
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u32 tsc_khz;
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struct lguest_dma_info dma[LGUEST_MAX_DMA];
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/* Dead? */
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const char *dead;
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/* The GDT entries copied into lguest_ro_state when running. */
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struct desc_struct gdt[GDT_ENTRIES];
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/* The IDT entries: some copied into lguest_ro_state when running. */
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struct desc_struct idt[FIRST_EXTERNAL_VECTOR+LGUEST_IRQS];
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struct desc_struct syscall_idt;
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/* Virtual clock device */
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struct hrtimer hrt;
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/* Pending virtual interrupts */
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DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
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};
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extern struct lguest lguests[];
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extern struct mutex lguest_lock;
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/* core.c: */
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u32 lgread_u32(struct lguest *lg, unsigned long addr);
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void lgwrite_u32(struct lguest *lg, unsigned long addr, u32 val);
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void lgread(struct lguest *lg, void *buf, unsigned long addr, unsigned len);
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void lgwrite(struct lguest *lg, unsigned long, const void *buf, unsigned len);
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int find_free_guest(void);
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int lguest_address_ok(const struct lguest *lg,
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unsigned long addr, unsigned long len);
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int run_guest(struct lguest *lg, unsigned long __user *user);
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/* interrupts_and_traps.c: */
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void maybe_do_interrupt(struct lguest *lg);
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int deliver_trap(struct lguest *lg, unsigned int num);
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void load_guest_idt_entry(struct lguest *lg, unsigned int i, u32 low, u32 hi);
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void guest_set_stack(struct lguest *lg, u32 seg, u32 esp, unsigned int pages);
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void pin_stack_pages(struct lguest *lg);
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void setup_default_idt_entries(struct lguest_ro_state *state,
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const unsigned long *def);
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void copy_traps(const struct lguest *lg, struct desc_struct *idt,
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const unsigned long *def);
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void guest_set_clockevent(struct lguest *lg, unsigned long delta);
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void init_clockdev(struct lguest *lg);
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/* segments.c: */
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void setup_default_gdt_entries(struct lguest_ro_state *state);
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void setup_guest_gdt(struct lguest *lg);
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void load_guest_gdt(struct lguest *lg, unsigned long table, u32 num);
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void guest_load_tls(struct lguest *lg, unsigned long tls_array);
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void copy_gdt(const struct lguest *lg, struct desc_struct *gdt);
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void copy_gdt_tls(const struct lguest *lg, struct desc_struct *gdt);
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/* page_tables.c: */
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int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
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void free_guest_pagetable(struct lguest *lg);
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void guest_new_pagetable(struct lguest *lg, unsigned long pgtable);
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void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 i);
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void guest_pagetable_clear_all(struct lguest *lg);
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void guest_pagetable_flush_user(struct lguest *lg);
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void guest_set_pte(struct lguest *lg, unsigned long cr3,
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unsigned long vaddr, gpte_t val);
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void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages);
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int demand_page(struct lguest *info, unsigned long cr2, int errcode);
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void pin_page(struct lguest *lg, unsigned long vaddr);
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/* lguest_user.c: */
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int lguest_device_init(void);
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void lguest_device_remove(void);
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/* io.c: */
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void lguest_io_init(void);
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int bind_dma(struct lguest *lg,
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unsigned long key, unsigned long udma, u16 numdmas, u8 interrupt);
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void send_dma(struct lguest *info, unsigned long key, unsigned long udma);
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void release_all_dma(struct lguest *lg);
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unsigned long get_dma_buffer(struct lguest *lg, unsigned long key,
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unsigned long *interrupt);
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/* hypercalls.c: */
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void do_hypercalls(struct lguest *lg);
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void write_timestamp(struct lguest *lg);
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/*L:035
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* Let's step aside for the moment, to study one important routine that's used
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* widely in the Host code.
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*
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* There are many cases where the Guest does something invalid, like pass crap
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* to a hypercall. Since only the Guest kernel can make hypercalls, it's quite
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* acceptable to simply terminate the Guest and give the Launcher a nicely
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* formatted reason. It's also simpler for the Guest itself, which doesn't
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* need to check most hypercalls for "success"; if you're still running, it
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* succeeded.
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*
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* Once this is called, the Guest will never run again, so most Host code can
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* call this then continue as if nothing had happened. This means many
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* functions don't have to explicitly return an error code, which keeps the
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* code simple.
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*
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* It also means that this can be called more than once: only the first one is
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* remembered. The only trick is that we still need to kill the Guest even if
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* we can't allocate memory to store the reason. Linux has a neat way of
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* packing error codes into invalid pointers, so we use that here.
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*
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* Like any macro which uses an "if", it is safely wrapped in a run-once "do {
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* } while(0)".
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*/
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#define kill_guest(lg, fmt...) \
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do { \
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if (!(lg)->dead) { \
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(lg)->dead = kasprintf(GFP_ATOMIC, fmt); \
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if (!(lg)->dead) \
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(lg)->dead = ERR_PTR(-ENOMEM); \
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} \
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} while(0)
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/* (End of aside) :*/
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static inline unsigned long guest_pa(struct lguest *lg, unsigned long vaddr)
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{
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return vaddr - lg->page_offset;
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}
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#endif /* __ASSEMBLY__ */
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#endif /* _LGUEST_H */
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