lguest: add operations to get/set a register from the Launcher. (18c13737) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/lguest/core.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -208,6 +208,14 @@ void __lgwrite(struct lg_cpu cpu, unsigned long addr, const void b,
		*/
		int run_guest(struct lg_cpu cpu, unsigned long __user user)
		{
		/* If the launcher asked for a register with LHREQ_GETREG */
		if (cpu->reg_read) {
		if (put_user(*cpu->reg_read, user))
		return -EFAULT;
		cpu->reg_read = NULL;
		return sizeof(*cpu->reg_read);
		}

		/* We stop running once the Guest is dead. */
		while (!cpu->lg->dead) {
		unsigned int irq;

drivers/lguest/lg.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -52,6 +52,8 @@ struct lg_cpu {

		unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */

		unsigned long reg_read; / register from LHREQ_GETREG */

		/* At end of a page shared mapped over lguest_pages in guest. */
		unsigned long regs_page;
		struct lguest_regs *regs;
		@@ -210,6 +212,7 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu);
		int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
		int lguest_arch_do_hcall(struct lg_cpu cpu, struct hcall_args args);
		void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start);
		unsigned long lguest_arch_regptr(struct lg_cpu cpu, size_t reg_off, bool any);

		/* <arch>/switcher.S: */
		extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];

drivers/lguest/lguest_user.c

+49 −0

Original line number	Diff line number	Diff line
		@@ -173,6 +173,51 @@ static int attach_eventfd(struct lguest lg, const unsigned long __user input)
		return err;
		}

		/* The Launcher can get the registers, and also set some of them. */
		static int getreg_setup(struct lg_cpu cpu, const unsigned long __user input)
		{
		unsigned long which;

		/* We re-use the ptrace structure to specify which register to read. */
		if (get_user(which, input) != 0)
		return -EFAULT;

		/*
		* We set up the cpu register pointer, and their next read will
		* actually get the value (instead of running the guest).
		*
		* The last argument 'true' says we can access any register.
		*/
		cpu->reg_read = lguest_arch_regptr(cpu, which, true);
		if (!cpu->reg_read)
		return -ENOENT;

		/* And because this is a write() call, we return the length used. */
		return sizeof(unsigned long) * 2;
		}

		static int setreg(struct lg_cpu cpu, const unsigned long __user input)
		{
		unsigned long which, value, *reg;

		/* We re-use the ptrace structure to specify which register to read. */
		if (get_user(which, input) != 0)
		return -EFAULT;
		input++;
		if (get_user(value, input) != 0)
		return -EFAULT;

		/* The last argument 'false' means we can't access all registers. */
		reg = lguest_arch_regptr(cpu, which, false);
		if (!reg)
		return -ENOENT;

		*reg = value;

		/* And because this is a write() call, we return the length used. */
		return sizeof(unsigned long) * 3;
		}

		/*L:050
		* Sending an interrupt is done by writing LHREQ_IRQ and an interrupt
		* number to /dev/lguest.
		@@ -434,6 +479,10 @@ static ssize_t write(struct file file, const char __user in,
		return user_send_irq(cpu, input);
		case LHREQ_EVENTFD:
		return attach_eventfd(lg, input);
		case LHREQ_GETREG:
		return getreg_setup(cpu, input);
		case LHREQ_SETREG:
		return setreg(cpu, input);
		default:
		return -EINVAL;
		}

drivers/lguest/x86/core.c

+46 −0

Original line number	Diff line number	Diff line
		@@ -181,6 +181,52 @@ static void run_guest_once(struct lg_cpu cpu, struct lguest_pages pages)
		}
		/:/

		unsigned long lguest_arch_regptr(struct lg_cpu cpu, size_t reg_off, bool any)
		{
		switch (reg_off) {
		case offsetof(struct pt_regs, bx):
		return &cpu->regs->ebx;
		case offsetof(struct pt_regs, cx):
		return &cpu->regs->ecx;
		case offsetof(struct pt_regs, dx):
		return &cpu->regs->edx;
		case offsetof(struct pt_regs, si):
		return &cpu->regs->esi;
		case offsetof(struct pt_regs, di):
		return &cpu->regs->edi;
		case offsetof(struct pt_regs, bp):
		return &cpu->regs->ebp;
		case offsetof(struct pt_regs, ax):
		return &cpu->regs->eax;
		case offsetof(struct pt_regs, ip):
		return &cpu->regs->eip;
		case offsetof(struct pt_regs, sp):
		return &cpu->regs->esp;
		}

		/* Launcher can read these, but we don't allow any setting. */
		if (any) {
		switch (reg_off) {
		case offsetof(struct pt_regs, ds):
		return &cpu->regs->ds;
		case offsetof(struct pt_regs, es):
		return &cpu->regs->es;
		case offsetof(struct pt_regs, fs):
		return &cpu->regs->fs;
		case offsetof(struct pt_regs, gs):
		return &cpu->regs->gs;
		case offsetof(struct pt_regs, cs):
		return &cpu->regs->cs;
		case offsetof(struct pt_regs, flags):
		return &cpu->regs->eflags;
		case offsetof(struct pt_regs, ss):
		return &cpu->regs->ss;
		}
		}

		return NULL;
		}

		/*M:002
		* There are hooks in the scheduler which we can register to tell when we
		* get kicked off the CPU (preempt_notifier_register()). This would allow us

include/linux/lguest_launcher.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -63,6 +63,8 @@ enum lguest_req
		LHREQ_IRQ, /* + irq */
		LHREQ_BREAK, /* No longer used */
		LHREQ_EVENTFD, /* + address, fd. */
		LHREQ_GETREG, /* + offset within struct pt_regs (then read value). */
		LHREQ_SETREG, /* + offset within struct pt_regs, value. */
		};

		/*