diff options
Diffstat (limited to 'drivers/lguest/hypercalls.c')
| -rw-r--r-- | drivers/lguest/hypercalls.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c new file mode 100644 index 000000000000..ea52ca451f74 --- /dev/null +++ b/drivers/lguest/hypercalls.c @@ -0,0 +1,192 @@ +/* Actual hypercalls, which allow guests to actually do something. + 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 <asm/page.h> +#include <asm/pgtable.h> +#include <irq_vectors.h> +#include "lg.h" + +static void do_hcall(struct lguest *lg, struct lguest_regs *regs) +{ + switch (regs->eax) { + case LHCALL_FLUSH_ASYNC: + break; + case LHCALL_LGUEST_INIT: + kill_guest(lg, "already have lguest_data"); + break; + case LHCALL_CRASH: { + char msg[128]; + lgread(lg, msg, regs->edx, sizeof(msg)); + msg[sizeof(msg)-1] = '\0'; + kill_guest(lg, "CRASH: %s", msg); + break; + } + case LHCALL_FLUSH_TLB: + if (regs->edx) + guest_pagetable_clear_all(lg); + else + guest_pagetable_flush_user(lg); + break; + case LHCALL_GET_WALLCLOCK: { + struct timespec ts; + ktime_get_real_ts(&ts); + regs->eax = ts.tv_sec; + break; + } + case LHCALL_BIND_DMA: + regs->eax = bind_dma(lg, regs->edx, regs->ebx, + regs->ecx >> 8, regs->ecx & 0xFF); + break; + case LHCALL_SEND_DMA: + send_dma(lg, regs->edx, regs->ebx); + break; + case LHCALL_LOAD_GDT: + load_guest_gdt(lg, regs->edx, regs->ebx); + break; + case LHCALL_LOAD_IDT_ENTRY: + load_guest_idt_entry(lg, regs->edx, regs->ebx, regs->ecx); + break; + case LHCALL_NEW_PGTABLE: + guest_new_pagetable(lg, regs->edx); + break; + case LHCALL_SET_STACK: + guest_set_stack(lg, regs->edx, regs->ebx, regs->ecx); + break; + case LHCALL_SET_PTE: + guest_set_pte(lg, regs->edx, regs->ebx, mkgpte(regs->ecx)); + break; + case LHCALL_SET_PMD: + guest_set_pmd(lg, regs->edx, regs->ebx); + break; + case LHCALL_LOAD_TLS: + guest_load_tls(lg, regs->edx); + break; + case LHCALL_SET_CLOCKEVENT: + guest_set_clockevent(lg, regs->edx); + break; + case LHCALL_TS: + lg->ts = regs->edx; + break; + case LHCALL_HALT: + lg->halted = 1; + break; + default: + kill_guest(lg, "Bad hypercall %li\n", regs->eax); + } +} + +/* We always do queued calls before actual hypercall. */ +static void do_async_hcalls(struct lguest *lg) +{ + unsigned int i; + u8 st[LHCALL_RING_SIZE]; + + if (copy_from_user(&st, &lg->lguest_data->hcall_status, sizeof(st))) + return; + + for (i = 0; i < ARRAY_SIZE(st); i++) { + struct lguest_regs regs; + unsigned int n = lg->next_hcall; + + if (st[n] == 0xFF) + break; + + if (++lg->next_hcall == LHCALL_RING_SIZE) + lg->next_hcall = 0; + + if (get_user(regs.eax, &lg->lguest_data->hcalls[n].eax) + || get_user(regs.edx, &lg->lguest_data->hcalls[n].edx) + || get_user(regs.ecx, &lg->lguest_data->hcalls[n].ecx) + || get_user(regs.ebx, &lg->lguest_data->hcalls[n].ebx)) { + kill_guest(lg, "Fetching async hypercalls"); + break; + } + + do_hcall(lg, ®s); + if (put_user(0xFF, &lg->lguest_data->hcall_status[n])) { + kill_guest(lg, "Writing result for async hypercall"); + break; + } + + if (lg->dma_is_pending) + break; + } +} + +static void initialize(struct lguest *lg) +{ + u32 tsc_speed; + + if (lg->regs->eax != LHCALL_LGUEST_INIT) { + kill_guest(lg, "hypercall %li before LGUEST_INIT", + lg->regs->eax); + return; + } + + /* We only tell the guest to use the TSC if it's reliable. */ + if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable()) + tsc_speed = tsc_khz; + else + tsc_speed = 0; + + lg->lguest_data = (struct lguest_data __user *)lg->regs->edx; + /* We check here so we can simply copy_to_user/from_user */ + if (!lguest_address_ok(lg, lg->regs->edx, sizeof(*lg->lguest_data))) { + kill_guest(lg, "bad guest page %p", lg->lguest_data); + return; + } + if (get_user(lg->noirq_start, &lg->lguest_data->noirq_start) + || get_user(lg->noirq_end, &lg->lguest_data->noirq_end) + /* We reserve the top pgd entry. */ + || put_user(4U*1024*1024, &lg->lguest_data->reserve_mem) + || put_user(tsc_speed, &lg->lguest_data->tsc_khz) + || put_user(lg->guestid, &lg->lguest_data->guestid)) + kill_guest(lg, "bad guest page %p", lg->lguest_data); + + /* 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 Guest might be referring to + * the old (read-only) page. */ + guest_pagetable_clear_all(lg); +} + +/* Even if we go out to userspace and come back, we don't want to do + * the hypercall again. */ +static void clear_hcall(struct lguest *lg) +{ + lg->regs->trapnum = 255; +} + +void do_hypercalls(struct lguest *lg) +{ + if (unlikely(!lg->lguest_data)) { + if (lg->regs->trapnum == LGUEST_TRAP_ENTRY) { + initialize(lg); + clear_hcall(lg); + } + return; + } + + do_async_hcalls(lg); + if (!lg->dma_is_pending && lg->regs->trapnum == LGUEST_TRAP_ENTRY) { + do_hcall(lg, lg->regs); + clear_hcall(lg); + } +} |