5dea1c88ed
The Host used to create some page tables for the Guest to use at the
top of Guest memory; it would then tell the Guest where this was. In
particular, it created linear mappings for 0 and 0xC0000000 addresses
because lguest used to switch to its real page tables quite late in
boot.
However, since d50d8fe19 Linux initialized boot page tables in
head_32.S even before the "are we lguest?" boot jump. So, now we can
simplify things: the Host pagetable code assumes 1:1 linear mapping
until it first calls the LHCALL_NEW_PGTABLE hypercall, which we now do
before we reach C code.
This also means that the Host doesn't need to know anything about the
Guest's PAGE_OFFSET. (Non-Linux guests might not even have such a
thing).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
261 lines
8.1 KiB
C
261 lines
8.1 KiB
C
#ifndef _LGUEST_H
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#define _LGUEST_H
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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/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/hrtimer.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <asm/lguest.h>
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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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struct pgdir {
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unsigned long gpgdir;
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pgd_t *pgdir;
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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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/* 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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struct lg_cpu {
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unsigned int id;
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struct lguest *lg;
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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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u32 cr2;
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int ts;
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u32 esp1;
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u16 ss1;
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/* Bitmap of what has changed: see CHANGED_* above. */
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int changed;
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unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */
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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_pages *last_pages;
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/* Initialization mode: linear map everything. */
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bool linear_pages;
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int cpu_pgd; /* Which pgd this cpu is currently using */
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/* If a hypercall was asked for, this points to the arguments. */
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struct hcall_args *hcall;
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u32 next_hcall;
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/* Virtual clock device */
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struct hrtimer hrt;
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/* Did the Guest tell us to halt? */
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int halted;
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/* Pending virtual interrupts */
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DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
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struct lg_cpu_arch arch;
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};
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struct lg_eventfd {
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unsigned long addr;
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struct eventfd_ctx *event;
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};
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struct lg_eventfd_map {
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unsigned int num;
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struct lg_eventfd map[];
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};
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/* The private info the thread maintains about the guest. */
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struct lguest {
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struct lguest_data __user *lguest_data;
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struct lg_cpu cpus[NR_CPUS];
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unsigned int nr_cpus;
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u32 pfn_limit;
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/*
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* This provides the offset to the base of guest-physical memory in the
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* Launcher.
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*/
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void __user *mem_base;
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unsigned long kernel_address;
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struct pgdir pgdirs[4];
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unsigned long noirq_start, noirq_end;
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unsigned int stack_pages;
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u32 tsc_khz;
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struct lg_eventfd_map *eventfds;
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/* Dead? */
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const char *dead;
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};
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extern struct mutex lguest_lock;
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/* core.c: */
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bool lguest_address_ok(const struct lguest *lg,
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unsigned long addr, unsigned long len);
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void __lgread(struct lg_cpu *, void *, unsigned long, unsigned);
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void __lgwrite(struct lg_cpu *, unsigned long, const void *, unsigned);
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/*H:035
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* Using memory-copy operations like that is usually inconvient, so we
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* have the following helper macros which read and write a specific type (often
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* an unsigned long).
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*
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* This reads into a variable of the given type then returns that.
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*/
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#define lgread(cpu, addr, type) \
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({ type _v; __lgread((cpu), &_v, (addr), sizeof(_v)); _v; })
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/* This checks that the variable is of the given type, then writes it out. */
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#define lgwrite(cpu, addr, type, val) \
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do { \
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typecheck(type, val); \
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__lgwrite((cpu), (addr), &(val), sizeof(val)); \
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} while(0)
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/* (end of memory access helper routines) :*/
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int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
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/*
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* Helper macros to obtain the first 12 or the last 20 bits, this is only the
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* first step in the migration to the kernel types. pte_pfn is already defined
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* in the kernel.
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*/
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#define pgd_flags(x) (pgd_val(x) & ~PAGE_MASK)
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#define pgd_pfn(x) (pgd_val(x) >> PAGE_SHIFT)
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#define pmd_flags(x) (pmd_val(x) & ~PAGE_MASK)
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#define pmd_pfn(x) (pmd_val(x) >> PAGE_SHIFT)
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/* interrupts_and_traps.c: */
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unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more);
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void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more);
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void set_interrupt(struct lg_cpu *cpu, unsigned int irq);
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bool deliver_trap(struct lg_cpu *cpu, unsigned int num);
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void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,
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u32 low, u32 hi);
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void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages);
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void pin_stack_pages(struct lg_cpu *cpu);
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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 lg_cpu *cpu, struct desc_struct *idt,
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const unsigned long *def);
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void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
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bool send_notify_to_eventfd(struct lg_cpu *cpu);
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void init_clockdev(struct lg_cpu *cpu);
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bool check_syscall_vector(struct lguest *lg);
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int init_interrupts(void);
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void free_interrupts(void);
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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 lg_cpu *cpu);
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void load_guest_gdt_entry(struct lg_cpu *cpu, unsigned int i,
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u32 low, u32 hi);
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void guest_load_tls(struct lg_cpu *cpu, unsigned long tls_array);
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void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
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void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
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/* page_tables.c: */
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int init_guest_pagetable(struct lguest *lg);
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void free_guest_pagetable(struct lguest *lg);
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void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
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void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 i);
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#ifdef CONFIG_X86_PAE
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void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
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#endif
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void guest_pagetable_clear_all(struct lg_cpu *cpu);
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void guest_pagetable_flush_user(struct lg_cpu *cpu);
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void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
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unsigned long vaddr, pte_t val);
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void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages);
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bool demand_page(struct lg_cpu *cpu, unsigned long cr2, int errcode);
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void pin_page(struct lg_cpu *cpu, unsigned long vaddr);
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unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr);
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void page_table_guest_data_init(struct lg_cpu *cpu);
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/* <arch>/core.c: */
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void lguest_arch_host_init(void);
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void lguest_arch_host_fini(void);
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void lguest_arch_run_guest(struct lg_cpu *cpu);
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void lguest_arch_handle_trap(struct lg_cpu *cpu);
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int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
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int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
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void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start);
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/* <arch>/switcher.S: */
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extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
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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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/* hypercalls.c: */
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void do_hypercalls(struct lg_cpu *cpu);
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void write_timestamp(struct lg_cpu *cpu);
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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 can do 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(cpu, fmt...) \
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do { \
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if (!(cpu)->lg->dead) { \
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(cpu)->lg->dead = kasprintf(GFP_ATOMIC, fmt); \
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if (!(cpu)->lg->dead) \
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(cpu)->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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#endif /* __ASSEMBLY__ */
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#endif /* _LGUEST_H */
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