lguest: the host code
This is the code for the "lg.ko" module, which allows lguest guests to be launched. [akpm@linux-foundation.org: update for futex-new-private-futexes] [akpm@linux-foundation.org: build fix] [jmorris@namei.org: lguest: use hrtimers] [akpm@linux-foundation.org: x86_64 build fix] Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rusty Russell
committed by
Linus Torvalds
Linus Torvalds
parent
07ad157f6e
commit
d7e28ffe6c
192
drivers/lguest/hypercalls.c
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192
drivers/lguest/hypercalls.c
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/* Actual hypercalls, which allow guests to actually do something.
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Copyright (C) 2006 Rusty Russell IBM Corporation
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <linux/uaccess.h>
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#include <linux/syscalls.h>
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#include <linux/mm.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <irq_vectors.h>
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#include "lg.h"
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static void do_hcall(struct lguest *lg, struct lguest_regs *regs)
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{
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switch (regs->eax) {
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case LHCALL_FLUSH_ASYNC:
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break;
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case LHCALL_LGUEST_INIT:
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kill_guest(lg, "already have lguest_data");
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break;
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case LHCALL_CRASH: {
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char msg[128];
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lgread(lg, msg, regs->edx, sizeof(msg));
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msg[sizeof(msg)-1] = '\0';
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kill_guest(lg, "CRASH: %s", msg);
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break;
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}
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case LHCALL_FLUSH_TLB:
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if (regs->edx)
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guest_pagetable_clear_all(lg);
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else
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guest_pagetable_flush_user(lg);
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break;
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case LHCALL_GET_WALLCLOCK: {
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struct timespec ts;
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ktime_get_real_ts(&ts);
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regs->eax = ts.tv_sec;
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break;
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}
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case LHCALL_BIND_DMA:
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regs->eax = bind_dma(lg, regs->edx, regs->ebx,
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regs->ecx >> 8, regs->ecx & 0xFF);
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break;
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case LHCALL_SEND_DMA:
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send_dma(lg, regs->edx, regs->ebx);
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break;
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case LHCALL_LOAD_GDT:
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load_guest_gdt(lg, regs->edx, regs->ebx);
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break;
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case LHCALL_LOAD_IDT_ENTRY:
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load_guest_idt_entry(lg, regs->edx, regs->ebx, regs->ecx);
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break;
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case LHCALL_NEW_PGTABLE:
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guest_new_pagetable(lg, regs->edx);
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break;
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case LHCALL_SET_STACK:
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guest_set_stack(lg, regs->edx, regs->ebx, regs->ecx);
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break;
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case LHCALL_SET_PTE:
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guest_set_pte(lg, regs->edx, regs->ebx, mkgpte(regs->ecx));
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break;
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case LHCALL_SET_PMD:
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guest_set_pmd(lg, regs->edx, regs->ebx);
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break;
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case LHCALL_LOAD_TLS:
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guest_load_tls(lg, regs->edx);
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break;
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case LHCALL_SET_CLOCKEVENT:
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guest_set_clockevent(lg, regs->edx);
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break;
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case LHCALL_TS:
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lg->ts = regs->edx;
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break;
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case LHCALL_HALT:
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lg->halted = 1;
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break;
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default:
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kill_guest(lg, "Bad hypercall %li\n", regs->eax);
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}
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}
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/* We always do queued calls before actual hypercall. */
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static void do_async_hcalls(struct lguest *lg)
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{
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unsigned int i;
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u8 st[LHCALL_RING_SIZE];
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if (copy_from_user(&st, &lg->lguest_data->hcall_status, sizeof(st)))
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return;
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for (i = 0; i < ARRAY_SIZE(st); i++) {
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struct lguest_regs regs;
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unsigned int n = lg->next_hcall;
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if (st[n] == 0xFF)
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break;
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if (++lg->next_hcall == LHCALL_RING_SIZE)
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lg->next_hcall = 0;
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if (get_user(regs.eax, &lg->lguest_data->hcalls[n].eax)
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|| get_user(regs.edx, &lg->lguest_data->hcalls[n].edx)
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|| get_user(regs.ecx, &lg->lguest_data->hcalls[n].ecx)
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|| get_user(regs.ebx, &lg->lguest_data->hcalls[n].ebx)) {
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kill_guest(lg, "Fetching async hypercalls");
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break;
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}
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do_hcall(lg, ®s);
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if (put_user(0xFF, &lg->lguest_data->hcall_status[n])) {
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kill_guest(lg, "Writing result for async hypercall");
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break;
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}
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if (lg->dma_is_pending)
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break;
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}
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}
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static void initialize(struct lguest *lg)
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{
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u32 tsc_speed;
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if (lg->regs->eax != LHCALL_LGUEST_INIT) {
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kill_guest(lg, "hypercall %li before LGUEST_INIT",
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lg->regs->eax);
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return;
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}
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/* We only tell the guest to use the TSC if it's reliable. */
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if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable())
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tsc_speed = tsc_khz;
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else
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tsc_speed = 0;
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lg->lguest_data = (struct lguest_data __user *)lg->regs->edx;
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/* We check here so we can simply copy_to_user/from_user */
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if (!lguest_address_ok(lg, lg->regs->edx, sizeof(*lg->lguest_data))) {
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kill_guest(lg, "bad guest page %p", lg->lguest_data);
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return;
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}
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if (get_user(lg->noirq_start, &lg->lguest_data->noirq_start)
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|| get_user(lg->noirq_end, &lg->lguest_data->noirq_end)
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/* We reserve the top pgd entry. */
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|| put_user(4U*1024*1024, &lg->lguest_data->reserve_mem)
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|| put_user(tsc_speed, &lg->lguest_data->tsc_khz)
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|| put_user(lg->guestid, &lg->lguest_data->guestid))
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kill_guest(lg, "bad guest page %p", lg->lguest_data);
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/* This is the one case where the above accesses might have
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* been the first write to a Guest page. This may have caused
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* a copy-on-write fault, but the Guest might be referring to
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* the old (read-only) page. */
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guest_pagetable_clear_all(lg);
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}
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/* Even if we go out to userspace and come back, we don't want to do
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* the hypercall again. */
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static void clear_hcall(struct lguest *lg)
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{
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lg->regs->trapnum = 255;
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}
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void do_hypercalls(struct lguest *lg)
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{
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if (unlikely(!lg->lguest_data)) {
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if (lg->regs->trapnum == LGUEST_TRAP_ENTRY) {
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initialize(lg);
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clear_hcall(lg);
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}
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return;
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}
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do_async_hcalls(lg);
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if (!lg->dma_is_pending && lg->regs->trapnum == LGUEST_TRAP_ENTRY) {
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do_hcall(lg, lg->regs);
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clear_hcall(lg);
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}
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}
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