lguest: write more information to userspace about pending traps. (69a09dc1) · Commits · e / devices / android_kernel_oneplus_sm7250

drivers/lguest/core.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -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);
		}
		}

+4 −3

Original line number	Diff line number	Diff line
		@@ -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

+2 −1

Original line number	Diff line number	Diff line
		@@ -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 */

+9 −5

Original line number	Diff line number	Diff line
		@@ -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);

+13 −0

Original line number	Diff line number	Diff line
		@@ -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.