lguest: make hypercalls use the vcpu struct

this patch changes do_hcall() and do_async_hcall() interfaces (and obviously their
callers) to get a vcpu struct. Again, a vcpu services the hypercall, not the whole
guest
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/lguest/core.c

@@ -181,8 +181,8 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
 	/* We stop running once the Guest is dead. */
 	while (!lg->dead) {
 		/* First we run any hypercalls the Guest wants done. */
-		if (lg->hcall)
-			do_hypercalls(lg);
+		if (cpu->hcall)
+			do_hypercalls(cpu);
 
 		/* It's possible the Guest did a NOTIFY hypercall to the
 		 * Launcher, in which case we return from the read() now. */
@@ -234,7 +234,7 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
 		local_irq_enable();
 
 		/* Now we deal with whatever happened to the Guest. */
-		lguest_arch_handle_trap(lg);
+		lguest_arch_handle_trap(cpu);
 	}
 
 	if (lg->dead == ERR_PTR(-ERESTART))

drivers/lguest/hypercalls.c

@@ -29,8 +29,10 @@
 
 /*H:120 This is the core hypercall routine: where the Guest gets what it wants.
  * Or gets killed.  Or, in the case of LHCALL_CRASH, both. */
-static void do_hcall(struct lguest *lg, struct hcall_args *args)
+static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
 {
+	struct lguest *lg = cpu->lg;
+
 	switch (args->arg0) {
 	case LHCALL_FLUSH_ASYNC:
 		/* This call does nothing, except by breaking out of the Guest
@@ -93,7 +95,7 @@ static void do_hcall(struct lguest *lg, struct hcall_args *args)
 		break;
 	default:
 		/* It should be an architecture-specific hypercall. */
-		if (lguest_arch_do_hcall(lg, args))
+		if (lguest_arch_do_hcall(cpu, args))
 			kill_guest(lg, "Bad hypercall %li\n", args->arg0);
 	}
 }
@@ -106,10 +108,11 @@ static void do_hcall(struct lguest *lg, struct hcall_args *args)
  * Guest put them in the ring, but we also promise the Guest that they will
  * happen before any normal hypercall (which is why we check this before
  * checking for a normal hcall). */
-static void do_async_hcalls(struct lguest *lg)
+static void do_async_hcalls(struct lg_cpu *cpu)
 {
 	unsigned int i;
 	u8 st[LHCALL_RING_SIZE];
+	struct lguest *lg = cpu->lg;
 
 	/* For simplicity, we copy the entire call status array in at once. */
 	if (copy_from_user(&st, &lg->lguest_data->hcall_status, sizeof(st)))
@@ -121,7 +124,7 @@ static void do_async_hcalls(struct lguest *lg)
 		/* We remember where we were up to from last time.  This makes
 		 * sure that the hypercalls are done in the order the Guest
 		 * places them in the ring. */
-		unsigned int n = lg->next_hcall;
+		unsigned int n = cpu->next_hcall;
 
 		/* 0xFF means there's no call here (yet). */
 		if (st[n] == 0xFF)
@@ -129,8 +132,8 @@ static void do_async_hcalls(struct lguest *lg)
 
 		/* OK, we have hypercall.  Increment the "next_hcall" cursor,
 		 * and wrap back to 0 if we reach the end. */
-		if (++lg->next_hcall == LHCALL_RING_SIZE)
-			lg->next_hcall = 0;
+		if (++cpu->next_hcall == LHCALL_RING_SIZE)
+			cpu->next_hcall = 0;
 
 		/* Copy the hypercall arguments into a local copy of
 		 * the hcall_args struct. */
@@ -141,7 +144,7 @@ static void do_async_hcalls(struct lguest *lg)
 		}
 
 		/* Do the hypercall, same as a normal one. */
-		do_hcall(lg, &args);
+		do_hcall(cpu, &args);
 
 		/* Mark the hypercall done. */
 		if (put_user(0xFF, &lg->lguest_data->hcall_status[n])) {
@@ -158,16 +161,17 @@ static void do_async_hcalls(struct lguest *lg)
 
 /* Last of all, we look at what happens first of all.  The very first time the
  * Guest makes a hypercall, we end up here to set things up: */
-static void initialize(struct lguest *lg)
+static void initialize(struct lg_cpu *cpu)
 {
+	struct lguest *lg = cpu->lg;
 	/* You can't do anything until you're initialized.  The Guest knows the
 	 * rules, so we're unforgiving here. */
-	if (lg->hcall->arg0 != LHCALL_LGUEST_INIT) {
-		kill_guest(lg, "hypercall %li before INIT", lg->hcall->arg0);
+	if (cpu->hcall->arg0 != LHCALL_LGUEST_INIT) {
+		kill_guest(lg, "hypercall %li before INIT", cpu->hcall->arg0);
 		return;
 	}
 
-	if (lguest_arch_init_hypercalls(lg))
+	if (lguest_arch_init_hypercalls(cpu))
 		kill_guest(lg, "bad guest page %p", lg->lguest_data);
 
 	/* The Guest tells us where we're not to deliver interrupts by putting
@@ -196,27 +200,27 @@ static void initialize(struct lguest *lg)
  * Remember from the Guest, hypercalls come in two flavors: normal and
  * asynchronous.  This file handles both of types.
  */
-void do_hypercalls(struct lguest *lg)
+void do_hypercalls(struct lg_cpu *cpu)
 {
 	/* Not initialized yet?  This hypercall must do it. */
-	if (unlikely(!lg->lguest_data)) {
+	if (unlikely(!cpu->lg->lguest_data)) {
 		/* Set up the "struct lguest_data" */
-		initialize(lg);
+		initialize(cpu);
 		/* Hcall is done. */
-		lg->hcall = NULL;
+		cpu->hcall = NULL;
 		return;
 	}
 
 	/* The Guest has initialized.
 	 *
 	 * Look in the hypercall ring for the async hypercalls: */
-	do_async_hcalls(lg);
+	do_async_hcalls(cpu);
 
 	/* If we stopped reading the hypercall ring because the Guest did a
 	 * NOTIFY to the Launcher, we want to return now.  Otherwise we do
 	 * the hypercall. */
-	if (!lg->pending_notify) {
-		do_hcall(lg, lg->hcall);
+	if (!cpu->lg->pending_notify) {
+		do_hcall(cpu, cpu->hcall);
 		/* Tricky point: we reset the hcall pointer to mark the
 		 * hypercall as "done".  We use the hcall pointer rather than
 		 * the trap number to indicate a hypercall is pending.
@@ -227,7 +231,7 @@ void do_hypercalls(struct lguest *lg)
 		 * Launcher, the run_guest() loop will exit without running the
 		 * Guest.  When it comes back it would try to re-run the
 		 * hypercall. */
-		lg->hcall = NULL;
+		cpu->hcall = NULL;
 	}
 }
 

drivers/lguest/lg.h

@@ -43,6 +43,10 @@ struct lguest;
 struct lg_cpu {
 	unsigned int id;
 	struct lguest *lg;
+
+	/* If a hypercall was asked for, this points to the arguments. */
+	struct hcall_args *hcall;
+	u32 next_hcall;
 };
 
 /* The private info the thread maintains about the guest. */
@@ -65,13 +69,9 @@ struct lguest
 	u32 cr2;
 	int halted;
 	int ts;
-	u32 next_hcall;
 	u32 esp1;
 	u8 ss1;
 
-	/* If a hypercall was asked for, this points to the arguments. */
-	struct hcall_args *hcall;
-
 	/* Do we need to stop what we're doing and return to userspace? */
 	int break_out;
 	wait_queue_head_t break_wq;
@@ -178,9 +178,9 @@ void page_table_guest_data_init(struct lguest *lg);
 void lguest_arch_host_init(void);
 void lguest_arch_host_fini(void);
 void lguest_arch_run_guest(struct lg_cpu *cpu);
-void lguest_arch_handle_trap(struct lguest *lg);
-int lguest_arch_init_hypercalls(struct lguest *lg);
-int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args);
+void lguest_arch_handle_trap(struct lg_cpu *cpu);
+int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
+int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
 void lguest_arch_setup_regs(struct lguest *lg, unsigned long start);
 
 /* <arch>/switcher.S: */
@@ -191,7 +191,7 @@ int lguest_device_init(void);
 void lguest_device_remove(void);
 
 /* hypercalls.c: */
-void do_hypercalls(struct lguest *lg);
+void do_hypercalls(struct lg_cpu *cpu);
 void write_timestamp(struct lguest *lg);
 
 /*L:035

drivers/lguest/x86/core.c

@@ -283,8 +283,9 @@ static int emulate_insn(struct lguest *lg)
 }
 
 /*H:050 Once we've re-enabled interrupts, we look at why the Guest exited. */
-void lguest_arch_handle_trap(struct lguest *lg)
+void lguest_arch_handle_trap(struct lg_cpu *cpu)
 {
+	struct lguest *lg = cpu->lg;
 	switch (lg->regs->trapnum) {
 	case 13: /* We've intercepted a General Protection Fault. */
 		/* Check if this was one of those annoying IN or OUT
@@ -336,7 +337,7 @@ void lguest_arch_handle_trap(struct lguest *lg)
 	case LGUEST_TRAP_ENTRY:
 		/* Our 'struct hcall_args' maps directly over our regs: we set
 		 * up the pointer now to indicate a hypercall is pending. */
-		lg->hcall = (struct hcall_args *)lg->regs;
+		cpu->hcall = (struct hcall_args *)lg->regs;
 		return;
 	}
 
@@ -491,8 +492,10 @@ void __exit lguest_arch_host_fini(void)
 
 
 /*H:122 The i386-specific hypercalls simply farm out to the right functions. */
-int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args)
+int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
 {
+	struct lguest *lg = cpu->lg;
+
 	switch (args->arg0) {
 	case LHCALL_LOAD_GDT:
 		load_guest_gdt(lg, args->arg1, args->arg2);
@@ -511,13 +514,14 @@ int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args)
 }
 
 /*H:126 i386-specific hypercall initialization: */
-int lguest_arch_init_hypercalls(struct lguest *lg)
+int lguest_arch_init_hypercalls(struct lg_cpu *cpu)
 {
 	u32 tsc_speed;
+	struct lguest *lg = cpu->lg;
 
 	/* The pointer to the Guest's "struct lguest_data" is the only
 	 * argument.  We check that address now. */
-	if (!lguest_address_ok(lg, lg->hcall->arg1, sizeof(*lg->lguest_data)))
+	if (!lguest_address_ok(lg, cpu->hcall->arg1, sizeof(*lg->lguest_data)))
 		return -EFAULT;
 
 	/* Having checked it, we simply set lg->lguest_data to point straight
@@ -525,7 +529,7 @@ int lguest_arch_init_hypercalls(struct lguest *lg)
 	 * copy_to_user/from_user from now on, instead of lgread/write.  I put
 	 * this in to show that I'm not immune to writing stupid
 	 * optimizations. */
-	lg->lguest_data = lg->mem_base + lg->hcall->arg1;
+	lg->lguest_data = lg->mem_base + cpu->hcall->arg1;
 
 	/* We insist that the Time Stamp Counter exist and doesn't change with
 	 * cpu frequency.  Some devious chip manufacturers decided that TSC