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>
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@ -79,6 +79,9 @@ static void *guest_base;
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/* The maximum guest physical address allowed, and maximum possible. */
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static unsigned long guest_limit, guest_max;
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/* a per-cpu variable indicating whose vcpu is currently running */
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static unsigned int __thread cpu_id;
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/* This is our list of devices. */
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struct device_list
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{
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@ -557,7 +560,7 @@ static void wake_parent(int pipefd, int lguest_fd)
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else
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FD_CLR(-fd - 1, &devices.infds);
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} else /* Send LHREQ_BREAK command. */
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write(lguest_fd, args, sizeof(args));
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pwrite(lguest_fd, args, sizeof(args), cpu_id);
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}
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}
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@ -1530,7 +1533,8 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd)
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int readval;
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/* We read from the /dev/lguest device to run the Guest. */
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readval = read(lguest_fd, ¬ify_addr, sizeof(notify_addr));
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readval = pread(lguest_fd, ¬ify_addr,
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sizeof(notify_addr), cpu_id);
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/* One unsigned long means the Guest did HCALL_NOTIFY */
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if (readval == sizeof(notify_addr)) {
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@ -1540,7 +1544,7 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd)
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/* ENOENT means the Guest died. Reading tells us why. */
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} else if (errno == ENOENT) {
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char reason[1024] = { 0 };
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read(lguest_fd, reason, sizeof(reason)-1);
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pread(lguest_fd, reason, sizeof(reason)-1, cpu_id);
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errx(1, "%s", reason);
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/* ERESTART means that we need to reboot the guest */
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} else if (errno == ERESTART) {
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@ -1550,9 +1554,13 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd)
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} else if (errno != EAGAIN)
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err(1, "Running guest failed");
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/* Only service input on thread for CPU 0. */
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if (cpu_id != 0)
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continue;
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/* Service input, then unset the BREAK to release the Waker. */
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handle_input(lguest_fd);
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if (write(lguest_fd, args, sizeof(args)) < 0)
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if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
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err(1, "Resetting break");
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}
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}
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@ -1610,6 +1618,7 @@ int main(int argc, char *argv[])
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devices.lastdev = &devices.dev;
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devices.next_irq = 1;
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cpu_id = 0;
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/* We need to know how much memory so we can set up the device
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* descriptor and memory pages for the devices as we parse the command
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* line. So we quickly look through the arguments to find the amount
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