Allow guest to specify syscall vector to use.

(Based on Ron Minnich's LGUEST_PLAN9_SYSCALL patch).

This patch allows Guests to specify what system call vector they want,
and we try to reserve it.  We only allow one non-Linux system call
vector, to try to avoid DoS on the Host.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index 84c09082f27..a125109446d 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -530,6 +530,10 @@ int lguest_arch_init_hypercalls(struct lguest *lg)
         if (put_user(tsc_speed, &lg->lguest_data->tsc_khz))
                 return -EFAULT;
 
+        /* The interrupt code might not like the system call vector. */
+        if (!check_syscall_vector(lg))
+                kill_guest(lg, "bad syscall vector");
+
         return 0;
 }
 /* Now we've examined the hypercall code; our Guest can make requests.  There