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Commit e3283fa0 authored by Glauber de Oliveira Costa's avatar Glauber de Oliveira Costa Committed by Rusty Russell
Browse files

lguest: adapt launcher to per-cpuness 



This patch makes uses of pread() and pwrite() in lguest launcher
to communicate the vcpu id to the lguest driver. The id is kept in
a thread variable, which means we'll span in the future, vcpus as
threads. But right now, only the infrastructure is out there.

Signed-off-by: default avatarGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent badb1e04

Documentation/lguest/lguest.c

+13 −4
Original line number Diff line number Diff line
@@ -79,6 +79,9 @@ static void *guest_base; 
/* The maximum guest physical address allowed, and maximum possible. */

static unsigned long guest_limit, guest_max;



/* a per-cpu variable indicating whose vcpu is currently running */

static unsigned int __thread cpu_id;



/* This is our list of devices. */

struct device_list

{
@@ -557,7 +560,7 @@ static void wake_parent(int pipefd, int lguest_fd) 
			else

				FD_CLR(-fd - 1, &devices.infds);

		} else /* Send LHREQ_BREAK command. */

			write(lguest_fd, args, sizeof(args));

			pwrite(lguest_fd, args, sizeof(args), cpu_id);

	}

}
@@ -1530,7 +1533,8 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) 
		int readval;



		/* We read from the /dev/lguest device to run the Guest. */

		readval = read(lguest_fd, &notify_addr, sizeof(notify_addr));

		readval = pread(lguest_fd, &notify_addr,

				sizeof(notify_addr), cpu_id);



		/* One unsigned long means the Guest did HCALL_NOTIFY */

		if (readval == sizeof(notify_addr)) {
@@ -1540,7 +1544,7 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) 
		/* ENOENT means the Guest died.  Reading tells us why. */

		} else if (errno == ENOENT) {

			char reason[1024] = { 0 };

			read(lguest_fd, reason, sizeof(reason)-1);

			pread(lguest_fd, reason, sizeof(reason)-1, cpu_id);

			errx(1, "%s", reason);

		/* ERESTART means that we need to reboot the guest */

		} else if (errno == ERESTART) {
@@ -1550,9 +1554,13 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) 
		} else if (errno != EAGAIN)

			err(1, "Running guest failed");



		/* Only service input on thread for CPU 0. */

		if (cpu_id != 0)

			continue;



		/* Service input, then unset the BREAK to release the Waker. */

		handle_input(lguest_fd);

		if (write(lguest_fd, args, sizeof(args)) < 0)

		if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)

			err(1, "Resetting break");

	}

}
@@ -1610,6 +1618,7 @@ int main(int argc, char *argv[]) 
	devices.lastdev = &devices.dev;

	devices.next_irq = 1;



	cpu_id = 0;

	/* We need to know how much memory so we can set up the device

	 * descriptor and memory pages for the devices as we parse the command

	 * line.  So we quickly look through the arguments to find the amount