diff options
| -rw-r--r-- | arch/x86/include/asm/lguest.h | 7 | ||||
| -rw-r--r-- | arch/x86/lguest/boot.c | 3 | ||||
| -rw-r--r-- | arch/x86/lguest/head_32.S | 15 | ||||
| -rw-r--r-- | drivers/lguest/hypercalls.c | 5 | ||||
| -rw-r--r-- | drivers/lguest/interrupts_and_traps.c | 8 | ||||
| -rw-r--r-- | drivers/lguest/lg.h | 2 | ||||
| -rw-r--r-- | include/linux/lguest.h | 4 |
7 files changed, 18 insertions, 26 deletions
diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h index e2d4a4a..3bbc07a 100644 --- a/arch/x86/include/asm/lguest.h +++ b/arch/x86/include/asm/lguest.h @@ -20,13 +20,10 @@ extern unsigned long switcher_addr; /* Found in switcher.S */ extern unsigned long default_idt_entries[]; -/* Declarations for definitions in lguest_guest.S */ -extern char lguest_noirq_start[], lguest_noirq_end[]; +/* Declarations for definitions in arch/x86/lguest/head_32.S */ +extern char lguest_noirq_iret[]; extern const char lgstart_cli[], lgend_cli[]; -extern const char lgstart_sti[], lgend_sti[]; -extern const char lgstart_popf[], lgend_popf[]; extern const char lgstart_pushf[], lgend_pushf[]; -extern const char lgstart_iret[], lgend_iret[]; extern void lguest_iret(void); extern void lguest_init(void); diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 543510a..13616d7 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -87,8 +87,7 @@ struct lguest_data lguest_data = { .hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF }, - .noirq_start = (u32)lguest_noirq_start, - .noirq_end = (u32)lguest_noirq_end, + .noirq_iret = (u32)lguest_noirq_iret, .kernel_address = PAGE_OFFSET, .blocked_interrupts = { 1 }, /* Block timer interrupts */ .syscall_vec = SYSCALL_VECTOR, diff --git a/arch/x86/lguest/head_32.S b/arch/x86/lguest/head_32.S index 81678bf..d5ae63f 100644 --- a/arch/x86/lguest/head_32.S +++ b/arch/x86/lguest/head_32.S @@ -133,9 +133,8 @@ ENTRY(lg_restore_fl) ret /*:*/ -/* These demark the EIP range where host should never deliver interrupts. */ -.global lguest_noirq_start -.global lguest_noirq_end +/* These demark the EIP where host should never deliver interrupts. */ +.global lguest_noirq_iret /*M:004 * When the Host reflects a trap or injects an interrupt into the Guest, it @@ -174,12 +173,11 @@ ENTRY(lg_restore_fl) * * The second is harder: copying eflags to lguest_data.irq_enabled will turn * interrupts on before we're finished, so we could be interrupted before we - * return to userspace or wherever. Our solution to this is to surround the - * code with lguest_noirq_start: and lguest_noirq_end: labels. We tell the + * return to userspace or wherever. Our solution to this is to tell the * Host that it is *never* to interrupt us there, even if interrupts seem to be * enabled. (It's not necessary to protect pop instruction, since - * data gets updated only after it completes, so we end up surrounding - * just one instruction, iret). + * data gets updated only after it completes, so we only need to protect + * one instruction, iret). */ ENTRY(lguest_iret) pushl 2*4(%esp) @@ -190,6 +188,5 @@ ENTRY(lguest_iret) * prefix makes sure we use the stack segment, which is still valid. */ popl %ss:lguest_data+LGUEST_DATA_irq_enabled -lguest_noirq_start: +lguest_noirq_iret: iret -lguest_noirq_end: diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c index 1219af4..19a3228 100644 --- a/drivers/lguest/hypercalls.c +++ b/drivers/lguest/hypercalls.c @@ -211,10 +211,9 @@ static void initialize(struct lg_cpu *cpu) /* * The Guest tells us where we're not to deliver interrupts by putting - * the range of addresses into "struct lguest_data". + * the instruction address into "struct lguest_data". */ - if (get_user(cpu->lg->noirq_start, &cpu->lg->lguest_data->noirq_start) - || get_user(cpu->lg->noirq_end, &cpu->lg->lguest_data->noirq_end)) + if (get_user(cpu->lg->noirq_iret, &cpu->lg->lguest_data->noirq_iret)) kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data); /* diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c index 70dfcdc..6d4c072 100644 --- a/drivers/lguest/interrupts_and_traps.c +++ b/drivers/lguest/interrupts_and_traps.c @@ -204,8 +204,7 @@ void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more) * They may be in the middle of an iret, where they asked us never to * deliver interrupts. */ - if (cpu->regs->eip >= cpu->lg->noirq_start && - (cpu->regs->eip < cpu->lg->noirq_end)) + if (cpu->regs->eip == cpu->lg->noirq_iret) return; /* If they're halted, interrupts restart them. */ @@ -395,8 +394,9 @@ static bool direct_trap(unsigned int num) * 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. It can do this by pointing the trap gate at instructions - * within noirq_start and noirq_end, where it can safely disable interrupts. + * 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 diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h index 307e8b3..ac8ad04 100644 --- a/drivers/lguest/lg.h +++ b/drivers/lguest/lg.h @@ -102,7 +102,7 @@ struct lguest { struct pgdir pgdirs[4]; - unsigned long noirq_start, noirq_end; + unsigned long noirq_iret; unsigned int stack_pages; u32 tsc_khz; diff --git a/include/linux/lguest.h b/include/linux/lguest.h index 9962c6b..6db19f3 100644 --- a/include/linux/lguest.h +++ b/include/linux/lguest.h @@ -61,8 +61,8 @@ struct lguest_data { u32 tsc_khz; /* Fields initialized by the Guest at boot: */ - /* Instruction range to suppress interrupts even if enabled */ - unsigned long noirq_start, noirq_end; + /* Instruction to suppress interrupts even if enabled */ + unsigned long noirq_iret; /* Address above which page tables are all identical. */ unsigned long kernel_address; /* The vector to try to use for system calls (0x40 or 0x80). */ |
