pmfs: mount: Add mechanism to disable interrupts inside LCD.

We need a way to temporarily prevent external interrupts from
causing an LCD exit.

lcd-domains/arch/x86/include/asm/lcd_domains/create.h

@@ -54,6 +54,19 @@ struct lcd_arch_vmcs *lcd_arch_alloc_vmcs(int cpu);
  * Free @vmcs page(s).
  */
 void lcd_arch_free_vmcs(struct lcd_arch_vmcs *vmcs);
+/**
+ * Configure LCD so that external interrupts do not cause an
+ * unconditional exit.
+ */
+void lcd_arch_irq_disable(struct lcd_arch *lcd_arch);
+/**
+ * Configure LCD so that external interrupts *do* cause an
+ * unconditional exit.
+ *
+ * NOTE: Unlike local_irq_enable, this function *always*
+ * "re-enables" interrupts.
+ */
+void lcd_arch_irq_enable(struct lcd_arch *lcd_arch);
 
 /* Some internal data used in create */
 extern struct kmem_cache *lcd_arch_cache;

lcd-domains/arch/x86/include/asm/lcd_domains/liblcd.h

@@ -250,5 +250,14 @@ static inline void lcd_syscall_dump_stack(void)
 	lcd_syscall_no_args(LCD_SYSCALL_DUMP_STACK);
 }
 
+static inline void lcd_syscall_irq_disable(void)
+{
+	lcd_syscall_no_args(LCD_SYSCALL_IRQ_DISABLE);
+}
+
+static inline void lcd_syscall_irq_enable(void)
+{
+	lcd_syscall_no_args(LCD_SYSCALL_IRQ_ENABLE);
+}
 
 #endif /* ASM_LCD_DOMAINS_LIBLCD_H */

lcd-domains/arch/x86/microkernel/create.c

@@ -1036,3 +1036,28 @@ int lcd_arch_set_gva_root(struct lcd_arch *lcd_arch, gpa_t a)
 	vmx_put_cpu(lcd_arch);
 	return 0;
 }
+
+void lcd_arch_irq_disable(struct lcd_arch *lcd_arch)
+{
+	/*
+	 * Clear pin based external interrupt bit. NMIs will still
+	 * cause an exit.
+	 */
+	vmx_get_cpu(lcd_arch);
+	vmcs_write32(PIN_BASED_VM_EXEC_CONTROL,
+		lcd_global_vmcs_config.pin_based_exec_controls &
+		~PIN_BASED_EXT_INTR_MASK);
+	vmx_put_cpu(lcd_arch);
+}
+
+void lcd_arch_irq_enable(struct lcd_arch *lcd_arch)
+{
+	/*
+	 * Set pin based external interrupt bit.
+	 */
+	vmx_get_cpu(lcd_arch);
+	vmcs_write32(PIN_BASED_VM_EXEC_CONTROL,
+		lcd_global_vmcs_config.pin_based_exec_controls &
+		PIN_BASED_EXT_INTR_MASK);
+	vmx_put_cpu(lcd_arch);
+}

lcd-domains/include/liblcd/irq.h

+/*
+ * irq.h
+ *
+ * Enable and disable IRQs.
+ *
+ * Motivation: You want to configure the LCD so that
+ * external interrupts do not cause a VM exit. Note that
+ * if you invoke a hypercall that causes a VM exit, the
+ * microkernel may choose to enable interrupts, and may
+ * get preempted at that point.
+ */
+#ifdef LIBLCD_IRQ_H
+#define LIBLCD_IRQ_H
+
+/**
+ * lcd_irq_disable
+ *
+ * For isolated code, disables interrupts and prevents interrupts
+ * from causing a VM exit. Note that NMIs will still trigger an
+ * exit.
+ *
+ * This is a no-op for non-isolated code. You should use the
+ * regular local_irq_disable.
+ */
+void lcd_irq_disable(void);
+/**
+ * lcd_irq_enable
+ *
+ * For isolated code, unconditionally re-enables interrupts. Interrupts
+ * will cause a VM exit now.
+ *
+ * Again, this is a no-op for non-isolated code.
+ */
+void lcd_irq_enable(void);
+
+#endif /* LIBLCD_IRQ_H */

lcd-domains/include/liblcd/syscall.h

@@ -28,6 +28,8 @@ enum lcd_syscall {
 	LCD_SYSCALL_MMAP,
 	LCD_SYSCALL_MUNMAP,
 	LCD_SYSCALL_DUMP_STACK,
+	LCD_SYSCALL_IRQ_ENABLE,
+	LCD_SYSCALL_IRQ_DISABLE,
 };
 
 #endif /* LCD_DOMAINS_SYSCALL_H */

lcd-domains/kliblcd/irq.c

+/*
+ * irq.c
+ */
+#include <liblcd/irq.h>
+
+void lcd_irq_disable(void)
+{
+	return; /* no op */
+}
+
+void lcd_irq_enable(void)
+{
+	return; /* no op */
+}
+
+/* EXPORTS -------------------------------------------------- */
+
+EXPORT_SYMBOL(lcd_irq_disable);
+EXPORT_SYMBOL(lcd_irq_enable);

lcd-domains/liblcd/lcd-domains/irq.c

+/*
+ * irq.c
+ */
+
+#include <lcd_config/pre_hook.h>
+
+#include <asm/lcd_domains/liblcd.h>
+#include <liblcd/irq.h>
+
+#include <lcd_config/post_hook.h>
+
+void lcd_irq_disable(void)
+{
+	/* Disable interrupts inside the VM */
+	__asm__ ("cli");
+
+	/* Configure LCD so that external interrupts do not cause vm exit */
+	lcd_syscall_irq_disable();
+}
+
+
+void lcd_irq_enable(void)
+{
+	/* Disable interrupts inside the VM */
+	__asm__ ("sti");
+
+	/* Configure LCD so that external interrupts *do* cause a vm exit */
+	lcd_syscall_irq_enable();
+}

lcd-domains/microkernel/run.c

@@ -290,6 +290,16 @@ static int handle_syscall_exit(struct lcd *lcd, int *lcd_ret)
 	return 1; /* signal LCD has exited */
 }
 
+static int handle_syscall_irq_disable(struct lcd *lcd)
+{
+	lcd_arch_irq_disable(lcd->lcd_arch);
+}
+
+static int handle_syscall_irq_enable(struct lcd *lcd)
+{
+	lcd_arch_irq_enable(lcd->lcd_arch);
+}
+
 static int handle_syscall(struct lcd *lcd, int *lcd_ret)
 {
 	int syscall_id;
@@ -361,6 +371,12 @@ static int handle_syscall(struct lcd *lcd, int *lcd_ret)
 	case LCD_SYSCALL_DUMP_STACK:
 		ret = handle_syscall_dump_stack(lcd);
 		break;
+	case LCD_SYSCALL_IRQ_DISABLE:
+		ret = handle_syscall_irq_disable(lcd);
+		break;
+	case LCD_SYSCALL_IRQ_ENABLE:
+		ret = handle_syscall_irq_enable(lcd);
+		break;
 	default:
 		LCD_ERR("unimplemented syscall %d", syscall_id);
 		ret = -ENOSYS;
@@ -374,7 +390,7 @@ static int handle_syscall(struct lcd *lcd, int *lcd_ret)
 }
 
 /* RUN LOOP -------------------------------------------------- */
-
+int icount = 0;
 static int run_once(struct lcd *lcd, int *lcd_ret)
 {
 	int ret;
@@ -396,6 +412,7 @@ static int run_once(struct lcd *lcd, int *lcd_ret)
 		 * Continue
 		 */
 		ret = 0;
+		icount++;
 		goto out;
 	case LCD_ARCH_STATUS_EPT_FAULT:
 		LCD_ERR("ept fault");
@@ -475,6 +492,7 @@ static int main_for_lcd(struct lcd *lcd)
 			lcd_arch_dump_lcd(lcd->lcd_arch);
 			return ret;
 		} else if (ret == 1) {
+			LCD_MSG("icount is %d", icount);
 			/* lcd exited */
 			return lcd_ret;
 		} else {

lcd-domains/scripts/Kbuild.liblcd

@@ -24,6 +24,7 @@ lib-y += $(addprefix liblcd/lcd-domains/, \
 	sync_ipc.o \
 	ioremap.o \
 	trace.o \
+	irq.o \
 	)
 
 lib-y += $(addprefix liblcd/lib/, \

lcd-domains/scripts/Kbuild.microkernel

@@ -48,6 +48,7 @@ lcd_domains-y += $(addprefix kliblcd/, \
 	      module_load.o \
 	      sync_ipc.o \
 	      trace.o \
+	      irq.o \
 	      )
 
 # code shared by kliblcd and isolated liblcd