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-rw-r--r--drivers/lguest/interrupts_and_traps.c706
1 files changed, 0 insertions, 706 deletions
diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c
deleted file mode 100644
index 67392b6ab845..000000000000
--- a/drivers/lguest/interrupts_and_traps.c
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@@ -1,706 +0,0 @@
-/*P:800
- * Interrupts (traps) are complicated enough to earn their own file.
- * There are three classes of interrupts:
- *
- * 1) Real hardware interrupts which occur while we're running the Guest,
- * 2) Interrupts for virtual devices attached to the Guest, and
- * 3) Traps and faults from the Guest.
- *
- * Real hardware interrupts must be delivered to the Host, not the Guest.
- * Virtual interrupts must be delivered to the Guest, but we make them look
- * just like real hardware would deliver them. Traps from the Guest can be set
- * up to go directly back into the Guest, but sometimes the Host wants to see
- * them first, so we also have a way of "reflecting" them into the Guest as if
- * they had been delivered to it directly.
-:*/
-#include <linux/uaccess.h>
-#include <linux/interrupt.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include "lg.h"
-
-/* Allow Guests to use a non-128 (ie. non-Linux) syscall trap. */
-static unsigned int syscall_vector = IA32_SYSCALL_VECTOR;
-module_param(syscall_vector, uint, 0444);
-
-/* The address of the interrupt handler is split into two bits: */
-static unsigned long idt_address(u32 lo, u32 hi)
-{
- return (lo & 0x0000FFFF) | (hi & 0xFFFF0000);
-}
-
-/*
- * The "type" of the interrupt handler is a 4 bit field: we only support a
- * couple of types.
- */
-static int idt_type(u32 lo, u32 hi)
-{
- return (hi >> 8) & 0xF;
-}
-
-/* An IDT entry can't be used unless the "present" bit is set. */
-static bool idt_present(u32 lo, u32 hi)
-{
- return (hi & 0x8000);
-}
-
-/*
- * We need a helper to "push" a value onto the Guest's stack, since that's a
- * big part of what delivering an interrupt does.
- */
-static void push_guest_stack(struct lg_cpu *cpu, unsigned long *gstack, u32 val)
-{
- /* Stack grows upwards: move stack then write value. */
- *gstack -= 4;
- lgwrite(cpu, *gstack, u32, val);
-}
-
-/*H:210
- * The push_guest_interrupt_stack() routine saves Guest state on the stack for
- * an interrupt or trap. The mechanics of delivering traps and interrupts to
- * the Guest are the same, except some traps have an "error code" which gets
- * pushed onto the stack as well: the caller tells us if this is one.
- *
- * We set up the stack just like the CPU does for a real interrupt, so it's
- * identical for the Guest (and the standard "iret" instruction will undo
- * it).
- */
-static void push_guest_interrupt_stack(struct lg_cpu *cpu, bool has_err)
-{
- unsigned long gstack, origstack;
- u32 eflags, ss, irq_enable;
- unsigned long virtstack;
-
- /*
- * There are two cases for interrupts: one where the Guest is already
- * in the kernel, and a more complex one where the Guest is in
- * userspace. We check the privilege level to find out.
- */
- if ((cpu->regs->ss&0x3) != GUEST_PL) {
- /*
- * The Guest told us their kernel stack with the SET_STACK
- * hypercall: both the virtual address and the segment.
- */
- virtstack = cpu->esp1;
- ss = cpu->ss1;
-
- origstack = gstack = guest_pa(cpu, virtstack);
- /*
- * We push the old stack segment and pointer onto the new
- * stack: when the Guest does an "iret" back from the interrupt
- * handler the CPU will notice they're dropping privilege
- * levels and expect these here.
- */
- push_guest_stack(cpu, &gstack, cpu->regs->ss);
- push_guest_stack(cpu, &gstack, cpu->regs->esp);
- } else {
- /* We're staying on the same Guest (kernel) stack. */
- virtstack = cpu->regs->esp;
- ss = cpu->regs->ss;
-
- origstack = gstack = guest_pa(cpu, virtstack);
- }
-
- /*
- * Remember that we never let the Guest actually disable interrupts, so
- * the "Interrupt Flag" bit is always set. We copy that bit from the
- * Guest's "irq_enabled" field into the eflags word: we saw the Guest
- * copy it back in "lguest_iret".
- */
- eflags = cpu->regs->eflags;
- if (get_user(irq_enable, &cpu->lg->lguest_data->irq_enabled) == 0
- && !(irq_enable & X86_EFLAGS_IF))
- eflags &= ~X86_EFLAGS_IF;
-
- /*
- * An interrupt is expected to push three things on the stack: the old
- * "eflags" word, the old code segment, and the old instruction
- * pointer.
- */
- push_guest_stack(cpu, &gstack, eflags);
- push_guest_stack(cpu, &gstack, cpu->regs->cs);
- push_guest_stack(cpu, &gstack, cpu->regs->eip);
-
- /* For the six traps which supply an error code, we push that, too. */
- if (has_err)
- push_guest_stack(cpu, &gstack, cpu->regs->errcode);
-
- /* Adjust the stack pointer and stack segment. */
- cpu->regs->ss = ss;
- cpu->regs->esp = virtstack + (gstack - origstack);
-}
-
-/*
- * This actually makes the Guest start executing the given interrupt/trap
- * handler.
- *
- * "lo" and "hi" are the two parts of the Interrupt Descriptor Table for this
- * interrupt or trap. It's split into two parts for traditional reasons: gcc
- * on i386 used to be frightened by 64 bit numbers.
- */
-static void guest_run_interrupt(struct lg_cpu *cpu, u32 lo, u32 hi)
-{
- /* If we're already in the kernel, we don't change stacks. */
- if ((cpu->regs->ss&0x3) != GUEST_PL)
- cpu->regs->ss = cpu->esp1;
-
- /*
- * Set the code segment and the address to execute.
- */
- cpu->regs->cs = (__KERNEL_CS|GUEST_PL);
- cpu->regs->eip = idt_address(lo, hi);
-
- /*
- * Trapping always clears these flags:
- * TF: Trap flag
- * VM: Virtual 8086 mode
- * RF: Resume
- * NT: Nested task.
- */
- cpu->regs->eflags &=
- ~(X86_EFLAGS_TF|X86_EFLAGS_VM|X86_EFLAGS_RF|X86_EFLAGS_NT);
-
- /*
- * There are two kinds of interrupt handlers: 0xE is an "interrupt
- * gate" which expects interrupts to be disabled on entry.
- */
- if (idt_type(lo, hi) == 0xE)
- if (put_user(0, &cpu->lg->lguest_data->irq_enabled))
- kill_guest(cpu, "Disabling interrupts");
-}
-
-/* This restores the eflags word which was pushed on the stack by a trap */
-static void restore_eflags(struct lg_cpu *cpu)
-{
- /* This is the physical address of the stack. */
- unsigned long stack_pa = guest_pa(cpu, cpu->regs->esp);
-
- /*
- * Stack looks like this:
- * Address Contents
- * esp EIP
- * esp + 4 CS
- * esp + 8 EFLAGS
- */
- cpu->regs->eflags = lgread(cpu, stack_pa + 8, u32);
- cpu->regs->eflags &=
- ~(X86_EFLAGS_TF|X86_EFLAGS_VM|X86_EFLAGS_RF|X86_EFLAGS_NT);
-}
-
-/*H:205
- * Virtual Interrupts.
- *
- * interrupt_pending() returns the first pending interrupt which isn't blocked
- * by the Guest. It is called before every entry to the Guest, and just before
- * we go to sleep when the Guest has halted itself.
- */
-unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more)
-{
- unsigned int irq;
- DECLARE_BITMAP(blk, LGUEST_IRQS);
-
- /* If the Guest hasn't even initialized yet, we can do nothing. */
- if (!cpu->lg->lguest_data)
- return LGUEST_IRQS;
-
- /*
- * Take our "irqs_pending" array and remove any interrupts the Guest
- * wants blocked: the result ends up in "blk".
- */
- if (copy_from_user(&blk, cpu->lg->lguest_data->blocked_interrupts,
- sizeof(blk)))
- return LGUEST_IRQS;
- bitmap_andnot(blk, cpu->irqs_pending, blk, LGUEST_IRQS);
-
- /* Find the first interrupt. */
- irq = find_first_bit(blk, LGUEST_IRQS);
- *more = find_next_bit(blk, LGUEST_IRQS, irq+1);
-
- return irq;
-}
-
-/*
- * This actually diverts the Guest to running an interrupt handler, once an
- * interrupt has been identified by interrupt_pending().
- */
-void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more)
-{
- struct desc_struct *idt;
-
- BUG_ON(irq >= LGUEST_IRQS);
-
- /* If they're halted, interrupts restart them. */
- if (cpu->halted) {
- /* Re-enable interrupts. */
- if (put_user(X86_EFLAGS_IF, &cpu->lg->lguest_data->irq_enabled))
- kill_guest(cpu, "Re-enabling interrupts");
- cpu->halted = 0;
- } else {
- /* Otherwise we check if they have interrupts disabled. */
- u32 irq_enabled;
- if (get_user(irq_enabled, &cpu->lg->lguest_data->irq_enabled))
- irq_enabled = 0;
- if (!irq_enabled) {
- /* Make sure they know an IRQ is pending. */
- put_user(X86_EFLAGS_IF,
- &cpu->lg->lguest_data->irq_pending);
- return;
- }
- }
-
- /*
- * Look at the IDT entry the Guest gave us for this interrupt. The
- * first 32 (FIRST_EXTERNAL_VECTOR) entries are for traps, so we skip
- * over them.
- */
- idt = &cpu->arch.idt[FIRST_EXTERNAL_VECTOR+irq];
- /* If they don't have a handler (yet?), we just ignore it */
- if (idt_present(idt->a, idt->b)) {
- /* OK, mark it no longer pending and deliver it. */
- clear_bit(irq, cpu->irqs_pending);
-
- /*
- * They may be about to iret, where they asked us never to
- * deliver interrupts. In this case, we can emulate that iret
- * then immediately deliver the interrupt. This is basically
- * a noop: the iret would pop the interrupt frame and restore
- * eflags, and then we'd set it up again. So just restore the
- * eflags word and jump straight to the handler in this case.
- *
- * Denys Vlasenko points out that this isn't quite right: if
- * the iret was returning to userspace, then that interrupt
- * would reset the stack pointer (which the Guest told us
- * about via LHCALL_SET_STACK). But unless the Guest is being
- * *really* weird, that will be the same as the current stack
- * anyway.
- */
- if (cpu->regs->eip == cpu->lg->noirq_iret) {
- restore_eflags(cpu);
- } else {
- /*
- * set_guest_interrupt() takes a flag to say whether
- * this interrupt pushes an error code onto the stack
- * as well: virtual interrupts never do.
- */
- push_guest_interrupt_stack(cpu, false);
- }
- /* Actually make Guest cpu jump to handler. */
- guest_run_interrupt(cpu, idt->a, idt->b);
- }
-
- /*
- * Every time we deliver an interrupt, we update the timestamp in the
- * Guest's lguest_data struct. It would be better for the Guest if we
- * did this more often, but it can actually be quite slow: doing it
- * here is a compromise which means at least it gets updated every
- * timer interrupt.
- */
- write_timestamp(cpu);
-
- /*
- * If there are no other interrupts we want to deliver, clear
- * the pending flag.
- */
- if (!more)
- put_user(0, &cpu->lg->lguest_data->irq_pending);
-}
-
-/* And this is the routine when we want to set an interrupt for the Guest. */
-void set_interrupt(struct lg_cpu *cpu, unsigned int irq)
-{
- /*
- * Next time the Guest runs, the core code will see if it can deliver
- * this interrupt.
- */
- set_bit(irq, cpu->irqs_pending);
-
- /*
- * Make sure it sees it; it might be asleep (eg. halted), or running
- * the Guest right now, in which case kick_process() will knock it out.
- */
- if (!wake_up_process(cpu->tsk))
- kick_process(cpu->tsk);
-}
-/*:*/
-
-/*
- * Linux uses trap 128 for system calls. Plan9 uses 64, and Ron Minnich sent
- * me a patch, so we support that too. It'd be a big step for lguest if half
- * the Plan 9 user base were to start using it.
- *
- * Actually now I think of it, it's possible that Ron *is* half the Plan 9
- * userbase. Oh well.
- */
-bool could_be_syscall(unsigned int num)
-{
- /* Normal Linux IA32_SYSCALL_VECTOR or reserved vector? */
- return num == IA32_SYSCALL_VECTOR || num == syscall_vector;
-}
-
-/* The syscall vector it wants must be unused by Host. */
-bool check_syscall_vector(struct lguest *lg)
-{
- u32 vector;
-
- if (get_user(vector, &lg->lguest_data->syscall_vec))
- return false;
-
- return could_be_syscall(vector);
-}
-
-int init_interrupts(void)
-{
- /* If they want some strange system call vector, reserve it now */
- if (syscall_vector != IA32_SYSCALL_VECTOR) {
- if (test_bit(syscall_vector, used_vectors) ||
- vector_used_by_percpu_irq(syscall_vector)) {
- printk(KERN_ERR "lg: couldn't reserve syscall %u\n",
- syscall_vector);
- return -EBUSY;
- }
- set_bit(syscall_vector, used_vectors);
- }
-
- return 0;
-}
-
-void free_interrupts(void)
-{
- if (syscall_vector != IA32_SYSCALL_VECTOR)
- clear_bit(syscall_vector, used_vectors);
-}
-
-/*H:220
- * Now we've got the routines to deliver interrupts, delivering traps like
- * page fault is easy. The only trick is that Intel decided that some traps
- * should have error codes:
- */
-static bool has_err(unsigned int trap)
-{
- return (trap == 8 || (trap >= 10 && trap <= 14) || trap == 17);
-}
-
-/* deliver_trap() returns true if it could deliver the trap. */
-bool deliver_trap(struct lg_cpu *cpu, unsigned int num)
-{
- /*
- * Trap numbers are always 8 bit, but we set an impossible trap number
- * for traps inside the Switcher, so check that here.
- */
- if (num >= ARRAY_SIZE(cpu->arch.idt))
- return false;
-
- /*
- * Early on the Guest hasn't set the IDT entries (or maybe it put a
- * bogus one in): if we fail here, the Guest will be killed.
- */
- if (!idt_present(cpu->arch.idt[num].a, cpu->arch.idt[num].b))
- return false;
- push_guest_interrupt_stack(cpu, has_err(num));
- guest_run_interrupt(cpu, cpu->arch.idt[num].a,
- cpu->arch.idt[num].b);
- return true;
-}
-
-/*H:250
- * Here's the hard part: returning to the Host every time a trap happens
- * and then calling deliver_trap() and re-entering the Guest is slow.
- * Particularly because Guest userspace system calls are traps (usually trap
- * 128).
- *
- * So we'd like to set up the IDT to tell the CPU to deliver traps directly
- * into the Guest. This is possible, but the complexities cause the size of
- * this file to double! However, 150 lines of code is worth writing for taking
- * system calls down from 1750ns to 270ns. Plus, if lguest didn't do it, all
- * the other hypervisors would beat it up at lunchtime.
- *
- * This routine indicates if a particular trap number could be delivered
- * directly.
- *
- * Unfortunately, Linux 4.6 started using an interrupt gate instead of a
- * trap gate for syscalls, so this trick is ineffective. See Mastery for
- * how we could do this anyway...
- */
-static bool direct_trap(unsigned int num)
-{
- /*
- * Hardware interrupts don't go to the Guest at all (except system
- * call).
- */
- if (num >= FIRST_EXTERNAL_VECTOR && !could_be_syscall(num))
- return false;
-
- /*
- * The Host needs to see page faults (for shadow paging and to save the
- * fault address), general protection faults (in/out emulation) and
- * device not available (TS handling) and of course, the hypercall trap.
- */
- return num != 14 && num != 13 && num != 7 && num != LGUEST_TRAP_ENTRY;
-}
-/*:*/
-
-/*M:005
- * The Guest has the ability to turn its interrupt gates into trap gates,
- * if it is careful. The Host will let trap gates can go directly to the
- * Guest, but the Guest needs the interrupts atomically disabled for an
- * interrupt gate. The Host could provide a mechanism to register more
- * "no-interrupt" regions, and the Guest could point the trap gate at
- * instructions within that region, where it can safely disable interrupts.
- */
-
-/*M:006
- * The Guests do not use the sysenter (fast system call) instruction,
- * because it's hardcoded to enter privilege level 0 and so can't go direct.
- * It's about twice as fast as the older "int 0x80" system call, so it might
- * still be worthwhile to handle it in the Switcher and lcall down to the
- * Guest. The sysenter semantics are hairy tho: search for that keyword in
- * entry.S
-:*/
-
-/*H:260
- * When we make traps go directly into the Guest, we need to make sure
- * the kernel stack is valid (ie. mapped in the page tables). Otherwise, the
- * CPU trying to deliver the trap will fault while trying to push the interrupt
- * words on the stack: this is called a double fault, and it forces us to kill
- * the Guest.
- *
- * Which is deeply unfair, because (literally!) it wasn't the Guests' fault.
- */
-void pin_stack_pages(struct lg_cpu *cpu)
-{
- unsigned int i;
-
- /*
- * Depending on the CONFIG_4KSTACKS option, the Guest can have one or
- * two pages of stack space.
- */
- for (i = 0; i < cpu->lg->stack_pages; i++)
- /*
- * The stack grows *upwards*, so the address we're given is the
- * start of the page after the kernel stack. Subtract one to
- * get back onto the first stack page, and keep subtracting to
- * get to the rest of the stack pages.
- */
- pin_page(cpu, cpu->esp1 - 1 - i * PAGE_SIZE);
-}
-
-/*
- * Direct traps also mean that we need to know whenever the Guest wants to use
- * a different kernel stack, so we can change the guest TSS to use that
- * stack. The TSS entries expect a virtual address, so unlike most addresses
- * the Guest gives us, the "esp" (stack pointer) value here is virtual, not
- * physical.
- *
- * In Linux each process has its own kernel stack, so this happens a lot: we
- * change stacks on each context switch.
- */
-void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages)
-{
- /*
- * You're not allowed a stack segment with privilege level 0: bad Guest!
- */
- if ((seg & 0x3) != GUEST_PL)
- kill_guest(cpu, "bad stack segment %i", seg);
- /* We only expect one or two stack pages. */
- if (pages > 2)
- kill_guest(cpu, "bad stack pages %u", pages);
- /* Save where the stack is, and how many pages */
- cpu->ss1 = seg;
- cpu->esp1 = esp;
- cpu->lg->stack_pages = pages;
- /* Make sure the new stack pages are mapped */
- pin_stack_pages(cpu);
-}
-
-/*
- * All this reference to mapping stacks leads us neatly into the other complex
- * part of the Host: page table handling.
- */
-
-/*H:235
- * This is the routine which actually checks the Guest's IDT entry and
- * transfers it into the entry in "struct lguest":
- */
-static void set_trap(struct lg_cpu *cpu, struct desc_struct *trap,
- unsigned int num, u32 lo, u32 hi)
-{
- u8 type = idt_type(lo, hi);
-
- /* We zero-out a not-present entry */
- if (!idt_present(lo, hi)) {
- trap->a = trap->b = 0;
- return;
- }
-
- /* We only support interrupt and trap gates. */
- if (type != 0xE && type != 0xF)
- kill_guest(cpu, "bad IDT type %i", type);
-
- /*
- * We only copy the handler address, present bit, privilege level and
- * type. The privilege level controls where the trap can be triggered
- * manually with an "int" instruction. This is usually GUEST_PL,
- * except for system calls which userspace can use.
- */
- trap->a = ((__KERNEL_CS|GUEST_PL)<<16) | (lo&0x0000FFFF);
- trap->b = (hi&0xFFFFEF00);
-}
-
-/*H:230
- * While we're here, dealing with delivering traps and interrupts to the
- * Guest, we might as well complete the picture: how the Guest tells us where
- * it wants them to go. This would be simple, except making traps fast
- * requires some tricks.
- *
- * We saw the Guest setting Interrupt Descriptor Table (IDT) entries with the
- * LHCALL_LOAD_IDT_ENTRY hypercall before: that comes here.
- */
-void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int num, u32 lo, u32 hi)
-{
- /*
- * Guest never handles: NMI, doublefault, spurious interrupt or
- * hypercall. We ignore when it tries to set them.
- */
- if (num == 2 || num == 8 || num == 15 || num == LGUEST_TRAP_ENTRY)
- return;
-
- /*
- * Mark the IDT as changed: next time the Guest runs we'll know we have
- * to copy this again.
- */
- cpu->changed |= CHANGED_IDT;
-
- /* Check that the Guest doesn't try to step outside the bounds. */
- if (num >= ARRAY_SIZE(cpu->arch.idt))
- kill_guest(cpu, "Setting idt entry %u", num);
- else
- set_trap(cpu, &cpu->arch.idt[num], num, lo, hi);
-}
-
-/*
- * The default entry for each interrupt points into the Switcher routines which
- * simply return to the Host. The run_guest() loop will then call
- * deliver_trap() to bounce it back into the Guest.
- */
-static void default_idt_entry(struct desc_struct *idt,
- int trap,
- const unsigned long handler,
- const struct desc_struct *base)
-{
- /* A present interrupt gate. */
- u32 flags = 0x8e00;
-
- /*
- * Set the privilege level on the entry for the hypercall: this allows
- * the Guest to use the "int" instruction to trigger it.
- */
- if (trap == LGUEST_TRAP_ENTRY)
- flags |= (GUEST_PL << 13);
- else if (base)
- /*
- * Copy privilege level from what Guest asked for. This allows
- * debug (int 3) traps from Guest userspace, for example.
- */
- flags |= (base->b & 0x6000);
-
- /* Now pack it into the IDT entry in its weird format. */
- idt->a = (LGUEST_CS<<16) | (handler&0x0000FFFF);
- idt->b = (handler&0xFFFF0000) | flags;
-}
-
-/* When the Guest first starts, we put default entries into the IDT. */
-void setup_default_idt_entries(struct lguest_ro_state *state,
- const unsigned long *def)
-{
- unsigned int i;
-
- for (i = 0; i < ARRAY_SIZE(state->guest_idt); i++)
- default_idt_entry(&state->guest_idt[i], i, def[i], NULL);
-}
-
-/*H:240
- * We don't use the IDT entries in the "struct lguest" directly, instead
- * we copy them into the IDT which we've set up for Guests on this CPU, just
- * before we run the Guest. This routine does that copy.
- */
-void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
- const unsigned long *def)
-{
- unsigned int i;
-
- /*
- * We can simply copy the direct traps, otherwise we use the default
- * ones in the Switcher: they will return to the Host.
- */
- for (i = 0; i < ARRAY_SIZE(cpu->arch.idt); i++) {
- const struct desc_struct *gidt = &cpu->arch.idt[i];
-
- /* If no Guest can ever override this trap, leave it alone. */
- if (!direct_trap(i))
- continue;
-
- /*
- * Only trap gates (type 15) can go direct to the Guest.
- * Interrupt gates (type 14) disable interrupts as they are
- * entered, which we never let the Guest do. Not present
- * entries (type 0x0) also can't go direct, of course.
- *
- * If it can't go direct, we still need to copy the priv. level:
- * they might want to give userspace access to a software
- * interrupt.
- */
- if (idt_type(gidt->a, gidt->b) == 0xF)
- idt[i] = *gidt;
- else
- default_idt_entry(&idt[i], i, def[i], gidt);
- }
-}
-
-/*H:200
- * The Guest Clock.
- *
- * There are two sources of virtual interrupts. We saw one in lguest_user.c:
- * the Launcher sending interrupts for virtual devices. The other is the Guest
- * timer interrupt.
- *
- * The Guest uses the LHCALL_SET_CLOCKEVENT hypercall to tell us how long to
- * the next timer interrupt (in nanoseconds). We use the high-resolution timer
- * infrastructure to set a callback at that time.
- *
- * 0 means "turn off the clock".
- */
-void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta)
-{
- ktime_t expires;
-
- if (unlikely(delta == 0)) {
- /* Clock event device is shutting down. */
- hrtimer_cancel(&cpu->hrt);
- return;
- }
-
- /*
- * We use wallclock time here, so the Guest might not be running for
- * all the time between now and the timer interrupt it asked for. This
- * is almost always the right thing to do.
- */
- expires = ktime_add_ns(ktime_get_real(), delta);
- hrtimer_start(&cpu->hrt, expires, HRTIMER_MODE_ABS);
-}
-
-/* This is the function called when the Guest's timer expires. */
-static enum hrtimer_restart clockdev_fn(struct hrtimer *timer)
-{
- struct lg_cpu *cpu = container_of(timer, struct lg_cpu, hrt);
-
- /* Remember the first interrupt is the timer interrupt. */
- set_interrupt(cpu, 0);
- return HRTIMER_NORESTART;
-}
-
-/* This sets up the timer for this Guest. */
-void init_clockdev(struct lg_cpu *cpu)
-{
- hrtimer_init(&cpu->hrt, CLOCK_REALTIME, HRTIMER_MODE_ABS);
- cpu->hrt.function = clockdev_fn;
-}