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lguest: adapt launcher to per-cpuness

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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 <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Glauber de Oliveira Costa 2008-01-07 11:05:23 -02:00 committed by Rusty Russell
parent badb1e0402
commit e3283fa0cc
1 changed files with 13 additions and 4 deletions
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17
Documentation/lguest/lguest.c
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@ -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