Subject: adapt lguest launcher to per-cpuness Date: Mon, 7 Jan 2008 11:05:23 -0200 From: Glauber de Oliveira Costa 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: Glauber de Oliveira Costa Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -81,6 +81,9 @@ static void *guest_base; 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 @@ -558,7 +561,7 @@ static void wake_parent(int pipefd, int 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); } } @@ -1614,7 +1617,8 @@ static void __attribute__((noreturn)) ru int readval; /* We read from the /dev/lguest device to run the Guest. */ - readval = read(lguest_fd, ¬ify_addr, sizeof(notify_addr)); + readval = pread(lguest_fd, ¬ify_addr, + sizeof(notify_addr), cpu_id); /* One unsigned long means the Guest did HCALL_NOTIFY */ if (readval == sizeof(notify_addr)) { @@ -1624,7 +1628,7 @@ static void __attribute__((noreturn)) ru /* 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) { @@ -1634,9 +1638,13 @@ static void __attribute__((noreturn)) ru } 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"); } } @@ -1695,6 +1703,7 @@ int main(int argc, char *argv[]) devices.lastdev = NULL; 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