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authorGlauber de Oliveira Costa <gcosta@redhat.com>2008-01-07 11:05:23 -0200
committerRusty Russell <rusty@rustcorp.com.au>2008-01-30 22:50:05 +1100
commite3283fa0cc5c4f9bde52339a40da89297e51b481 (patch)
treec289c2681d2cedd5ee778a8a754417ab50946d8a /Documentation
parentbadb1e04028e3e029ff9447d4aeb162a84ad68c2 (diff)
downloadlinaro-lsk-e3283fa0cc5c4f9bde52339a40da89297e51b481.tar.gz
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: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/lguest/lguest.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 86cac3e622a..6c8a2386cd5 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -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