From: Rusty Russell Date: Wed, 11 Feb 2015 04:45:09 +0000 (+1030) Subject: lguest: write more information to userspace about pending traps. X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=69a09dc1742ffbb3b02f3a1e03da4801e96452e9;p=linux-beck.git lguest: write more information to userspace about pending traps. This is preparation for userspace handling MMIO and ioport accesses. Signed-off-by: Rusty Russell --- diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c index cdb2f9aa5860..9159dbc583f6 100644 --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -229,16 +229,17 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user) * It's possible the Guest did a NOTIFY hypercall to the * Launcher. */ - if (cpu->pending_notify) { + if (cpu->pending.trap) { /* * Does it just needs to write to a registered * eventfd (ie. the appropriate virtqueue thread)? */ if (!send_notify_to_eventfd(cpu)) { /* OK, we tell the main Launcher. */ - if (put_user(cpu->pending_notify, user)) + if (copy_to_user(user, &cpu->pending, + sizeof(cpu->pending))) return -EFAULT; - return sizeof(cpu->pending_notify); + return sizeof(cpu->pending); } } diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c index 83511eb0923d..5dd1fb8a6610 100644 --- a/drivers/lguest/hypercalls.c +++ b/drivers/lguest/hypercalls.c @@ -118,7 +118,8 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args) cpu->halted = 1; break; case LHCALL_NOTIFY: - cpu->pending_notify = args->arg1; + cpu->pending.trap = LGUEST_TRAP_ENTRY; + cpu->pending.addr = args->arg1; break; default: /* It should be an architecture-specific hypercall. */ @@ -189,7 +190,7 @@ static void do_async_hcalls(struct lg_cpu *cpu) * Stop doing hypercalls if they want to notify the Launcher: * it needs to service this first. */ - if (cpu->pending_notify) + if (cpu->pending.trap) break; } } @@ -280,7 +281,7 @@ void do_hypercalls(struct lg_cpu *cpu) * NOTIFY to the Launcher, we want to return now. Otherwise we do * the hypercall. */ - if (!cpu->pending_notify) { + if (!cpu->pending.trap) { do_hcall(cpu, cpu->hcall); /* * Tricky point: we reset the hcall pointer to mark the diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h index 1c98bf74fd68..020fec5bb072 100644 --- a/drivers/lguest/lg.h +++ b/drivers/lguest/lg.h @@ -50,7 +50,8 @@ struct lg_cpu { /* Bitmap of what has changed: see CHANGED_* above. */ int changed; - unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */ + /* Pending operation. */ + struct lguest_pending pending; unsigned long *reg_read; /* register from LHREQ_GETREG */ diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c index 7f14c152dd23..dcf9efd94cf4 100644 --- a/drivers/lguest/lguest_user.c +++ b/drivers/lguest/lguest_user.c @@ -29,6 +29,10 @@ bool send_notify_to_eventfd(struct lg_cpu *cpu) unsigned int i; struct lg_eventfd_map *map; + /* We only connect LHCALL_NOTIFY to event fds, not other traps. */ + if (cpu->pending.trap != LGUEST_TRAP_ENTRY) + return false; + /* * This "rcu_read_lock()" helps track when someone is still looking at * the (RCU-using) eventfds array. It's not actually a lock at all; @@ -52,9 +56,9 @@ bool send_notify_to_eventfd(struct lg_cpu *cpu) * we'll continue to use the old array and just won't see the new one. */ for (i = 0; i < map->num; i++) { - if (map->map[i].addr == cpu->pending_notify) { + if (map->map[i].addr == cpu->pending.addr) { eventfd_signal(map->map[i].event, 1); - cpu->pending_notify = 0; + cpu->pending.trap = 0; break; } } @@ -62,7 +66,7 @@ bool send_notify_to_eventfd(struct lg_cpu *cpu) rcu_read_unlock(); /* If we cleared the notification, it's because we found a match. */ - return cpu->pending_notify == 0; + return cpu->pending.trap == 0; } /*L:055 @@ -282,8 +286,8 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) * If we returned from read() last time because the Guest sent I/O, * clear the flag. */ - if (cpu->pending_notify) - cpu->pending_notify = 0; + if (cpu->pending.trap) + cpu->pending.trap = 0; /* Run the Guest until something interesting happens. */ return run_guest(cpu, (unsigned long __user *)user); diff --git a/include/linux/lguest_launcher.h b/include/linux/lguest_launcher.h index f27cae27b0c1..c4451ebece47 100644 --- a/include/linux/lguest_launcher.h +++ b/include/linux/lguest_launcher.h @@ -67,6 +67,19 @@ enum lguest_req LHREQ_SETREG, /* + offset within struct pt_regs, value. */ }; +/* + * This is what read() of the lguest fd populates. trap == + * LGUEST_TRAP_ENTRY for an LHCALL_NOTIFY (addr is the + * argument), 14 for a page fault in the MMIO region (addr is + * the trap address, insn is the instruction), or 13 for a GPF + * (insn is the instruction). + */ +struct lguest_pending { + __u8 trap; + __u8 insn[7]; + __u32 addr; +}; + /* * The alignment to use between consumer and producer parts of vring. * x86 pagesize for historical reasons. diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c index 3f7f2326cd9a..0e754d04876d 100644 --- a/tools/lguest/lguest.c +++ b/tools/lguest/lguest.c @@ -1820,17 +1820,21 @@ static void __attribute__((noreturn)) restart_guest(void) static void __attribute__((noreturn)) run_guest(void) { for (;;) { - unsigned long notify_addr; + struct lguest_pending notify; int readval; /* We read from the /dev/lguest device to run the Guest. */ - readval = pread(lguest_fd, ¬ify_addr, - sizeof(notify_addr), cpu_id); + readval = pread(lguest_fd, ¬ify, sizeof(notify), cpu_id); /* One unsigned long means the Guest did HCALL_NOTIFY */ - if (readval == sizeof(notify_addr)) { - verbose("Notify on address %#lx\n", notify_addr); - handle_output(notify_addr); + if (readval == sizeof(notify)) { + if (notify.trap == 0x1F) { + verbose("Notify on address %#08x\n", + notify.addr); + handle_output(notify.addr); + } else + errx(1, "Unknown trap %i addr %#08x\n", + notify.trap, notify.addr); /* ENOENT means the Guest died. Reading tells us why. */ } else if (errno == ENOENT) { char reason[1024] = { 0 };