From cc6d4fbcef328acdc9fa7023e69f39f753f72fe1 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 22 Oct 2007 11:03:30 +1000 Subject: Introduce "hcall" pointer to indicate pending hypercall. Currently we look at the "trapnum" to see if the Guest wants a hypercall. But once the hypercall is done we have to reset trapnum to a bogus value, otherwise if we exit to userspace and return, we'd run the same hypercall twice (that was a nasty bug to find!). This has two main effects: 1) When Jes's patch changes the hypercall args to be a generic "struct hcall_args" we simply change the type of "lg->hcall". It's set by arch code, so if it has to copy args or something it can do so, and point "hcall" into lg->arch somewhere. 2) Async hypercalls only get run when an actual hypercall is pending. This simplfies the code a little and is a more logical semantic. Signed-off-by: Rusty Russell --- drivers/lguest/core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/lguest/core.c') diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c index 06869a2d3b40..02556bae9e9f 100644 --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -198,10 +198,10 @@ int run_guest(struct lguest *lg, unsigned long __user *user) { /* We stop running once the Guest is dead. */ while (!lg->dead) { - /* First we run any hypercalls the Guest wants done: either in - * the hypercall ring in "struct lguest_data", or directly by - * using int 31 (LGUEST_TRAP_ENTRY). */ - do_hypercalls(lg); + /* First we run any hypercalls the Guest wants done. */ + if (lg->hcall) + do_hypercalls(lg); + /* It's possible the Guest did a SEND_DMA hypercall to the * Launcher, in which case we return from the read() now. */ if (lg->dma_is_pending) { -- cgit v1.2.1