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Diffstat (limited to 'drivers/lguest/hypercalls.c')
| -rw-r--r-- | drivers/lguest/hypercalls.c | 304 |
1 files changed, 0 insertions, 304 deletions
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c deleted file mode 100644 index 601f81c04873..000000000000 --- a/drivers/lguest/hypercalls.c +++ /dev/null @@ -1,304 +0,0 @@ -/*P:500 - * Just as userspace programs request kernel operations through a system - * call, the Guest requests Host operations through a "hypercall". You might - * notice this nomenclature doesn't really follow any logic, but the name has - * been around for long enough that we're stuck with it. As you'd expect, this - * code is basically a one big switch statement. -:*/ - -/* Copyright (C) 2006 Rusty Russell IBM Corporation - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA -*/ -#include <linux/uaccess.h> -#include <linux/syscalls.h> -#include <linux/mm.h> -#include <linux/ktime.h> -#include <asm/page.h> -#include <asm/pgtable.h> -#include "lg.h" - -/*H:120 - * This is the core hypercall routine: where the Guest gets what it wants. - * Or gets killed. Or, in the case of LHCALL_SHUTDOWN, both. - */ -static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args) -{ - switch (args->arg0) { - case LHCALL_FLUSH_ASYNC: - /* - * This call does nothing, except by breaking out of the Guest - * it makes us process all the asynchronous hypercalls. - */ - break; - case LHCALL_SEND_INTERRUPTS: - /* - * This call does nothing too, but by breaking out of the Guest - * it makes us process any pending interrupts. - */ - break; - case LHCALL_LGUEST_INIT: - /* - * You can't get here unless you're already initialized. Don't - * do that. - */ - kill_guest(cpu, "already have lguest_data"); - break; - case LHCALL_SHUTDOWN: { - char msg[128]; - /* - * Shutdown is such a trivial hypercall that we do it in five - * lines right here. - * - * If the lgread fails, it will call kill_guest() itself; the - * kill_guest() with the message will be ignored. - */ - __lgread(cpu, msg, args->arg1, sizeof(msg)); - msg[sizeof(msg)-1] = '\0'; - kill_guest(cpu, "CRASH: %s", msg); - if (args->arg2 == LGUEST_SHUTDOWN_RESTART) - cpu->lg->dead = ERR_PTR(-ERESTART); - break; - } - case LHCALL_FLUSH_TLB: - /* FLUSH_TLB comes in two flavors, depending on the argument: */ - if (args->arg1) - guest_pagetable_clear_all(cpu); - else - guest_pagetable_flush_user(cpu); - break; - - /* - * All these calls simply pass the arguments through to the right - * routines. - */ - case LHCALL_NEW_PGTABLE: - guest_new_pagetable(cpu, args->arg1); - break; - case LHCALL_SET_STACK: - guest_set_stack(cpu, args->arg1, args->arg2, args->arg3); - break; - case LHCALL_SET_PTE: -#ifdef CONFIG_X86_PAE - guest_set_pte(cpu, args->arg1, args->arg2, - __pte(args->arg3 | (u64)args->arg4 << 32)); -#else - guest_set_pte(cpu, args->arg1, args->arg2, __pte(args->arg3)); -#endif - break; - case LHCALL_SET_PGD: - guest_set_pgd(cpu->lg, args->arg1, args->arg2); - break; -#ifdef CONFIG_X86_PAE - case LHCALL_SET_PMD: - guest_set_pmd(cpu->lg, args->arg1, args->arg2); - break; -#endif - case LHCALL_SET_CLOCKEVENT: - guest_set_clockevent(cpu, args->arg1); - break; - case LHCALL_HALT: - /* Similarly, this sets the halted flag for run_guest(). */ - cpu->halted = 1; - break; - default: - /* It should be an architecture-specific hypercall. */ - if (lguest_arch_do_hcall(cpu, args)) - kill_guest(cpu, "Bad hypercall %li\n", args->arg0); - } -} - -/*H:124 - * Asynchronous hypercalls are easy: we just look in the array in the - * Guest's "struct lguest_data" to see if any new ones are marked "ready". - * - * We are careful to do these in order: obviously we respect the order the - * Guest put them in the ring, but we also promise the Guest that they will - * happen before any normal hypercall (which is why we check this before - * checking for a normal hcall). - */ -static void do_async_hcalls(struct lg_cpu *cpu) -{ - unsigned int i; - u8 st[LHCALL_RING_SIZE]; - - /* For simplicity, we copy the entire call status array in at once. */ - if (copy_from_user(&st, &cpu->lg->lguest_data->hcall_status, sizeof(st))) - return; - - /* We process "struct lguest_data"s hcalls[] ring once. */ - for (i = 0; i < ARRAY_SIZE(st); i++) { - struct hcall_args args; - /* - * We remember where we were up to from last time. This makes - * sure that the hypercalls are done in the order the Guest - * places them in the ring. - */ - unsigned int n = cpu->next_hcall; - - /* 0xFF means there's no call here (yet). */ - if (st[n] == 0xFF) - break; - - /* - * OK, we have hypercall. Increment the "next_hcall" cursor, - * and wrap back to 0 if we reach the end. - */ - if (++cpu->next_hcall == LHCALL_RING_SIZE) - cpu->next_hcall = 0; - - /* - * Copy the hypercall arguments into a local copy of the - * hcall_args struct. - */ - if (copy_from_user(&args, &cpu->lg->lguest_data->hcalls[n], - sizeof(struct hcall_args))) { - kill_guest(cpu, "Fetching async hypercalls"); - break; - } - - /* Do the hypercall, same as a normal one. */ - do_hcall(cpu, &args); - - /* Mark the hypercall done. */ - if (put_user(0xFF, &cpu->lg->lguest_data->hcall_status[n])) { - kill_guest(cpu, "Writing result for async hypercall"); - break; - } - - /* - * Stop doing hypercalls if they want to notify the Launcher: - * it needs to service this first. - */ - if (cpu->pending.trap) - break; - } -} - -/* - * Last of all, we look at what happens first of all. The very first time the - * Guest makes a hypercall, we end up here to set things up: - */ -static void initialize(struct lg_cpu *cpu) -{ - /* - * You can't do anything until you're initialized. The Guest knows the - * rules, so we're unforgiving here. - */ - if (cpu->hcall->arg0 != LHCALL_LGUEST_INIT) { - kill_guest(cpu, "hypercall %li before INIT", cpu->hcall->arg0); - return; - } - - if (lguest_arch_init_hypercalls(cpu)) - kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data); - - /* - * The Guest tells us where we're not to deliver interrupts by putting - * the instruction address into "struct lguest_data". - */ - if (get_user(cpu->lg->noirq_iret, &cpu->lg->lguest_data->noirq_iret)) - kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data); - - /* - * We write the current time into the Guest's data page once so it can - * set its clock. - */ - write_timestamp(cpu); - - /* page_tables.c will also do some setup. */ - page_table_guest_data_init(cpu); - - /* - * This is the one case where the above accesses might have been the - * first write to a Guest page. This may have caused a copy-on-write - * fault, but the old page might be (read-only) in the Guest - * pagetable. - */ - guest_pagetable_clear_all(cpu); -} -/*:*/ - -/*M:013 - * If a Guest reads from a page (so creates a mapping) that it has never - * written to, and then the Launcher writes to it (ie. the output of a virtual - * device), the Guest will still see the old page. In practice, this never - * happens: why would the Guest read a page which it has never written to? But - * a similar scenario might one day bite us, so it's worth mentioning. - * - * Note that if we used a shared anonymous mapping in the Launcher instead of - * mapping /dev/zero private, we wouldn't worry about cop-on-write. And we - * need that to switch the Launcher to processes (away from threads) anyway. -:*/ - -/*H:100 - * Hypercalls - * - * Remember from the Guest, hypercalls come in two flavors: normal and - * asynchronous. This file handles both of types. - */ -void do_hypercalls(struct lg_cpu *cpu) -{ - /* Not initialized yet? This hypercall must do it. */ - if (unlikely(!cpu->lg->lguest_data)) { - /* Set up the "struct lguest_data" */ - initialize(cpu); - /* Hcall is done. */ - cpu->hcall = NULL; - return; - } - - /* - * The Guest has initialized. - * - * Look in the hypercall ring for the async hypercalls: - */ - do_async_hcalls(cpu); - - /* - * If we stopped reading the hypercall ring because the Guest did a - * NOTIFY to the Launcher, we want to return now. Otherwise we do - * the hypercall. - */ - if (!cpu->pending.trap) { - do_hcall(cpu, cpu->hcall); - /* - * Tricky point: we reset the hcall pointer to mark the - * hypercall as "done". We use the hcall pointer rather than - * the trap number to indicate a hypercall is pending. - * Normally it doesn't matter: the Guest will run again and - * update the trap number before we come back here. - * - * However, if we are signalled or the Guest sends I/O to the - * Launcher, the run_guest() loop will exit without running the - * Guest. When it comes back it would try to re-run the - * hypercall. Finding that bug sucked. - */ - cpu->hcall = NULL; - } -} - -/* - * This routine supplies the Guest with time: it's used for wallclock time at - * initial boot and as a rough time source if the TSC isn't available. - */ -void write_timestamp(struct lg_cpu *cpu) -{ - struct timespec now; - ktime_get_real_ts(&now); - if (copy_to_user(&cpu->lg->lguest_data->time, - &now, sizeof(struct timespec))) - kill_guest(cpu, "Writing timestamp"); -} |