KVM: ia64: Define printk function for kvm-intel module

kvm-intel module is relocated to an isolated address space
with kernel, so it can't call host kernel's printk for debug
purpose. In the module, we implement the printk to output debug
info of vmm.

Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/ia64/include/asm/kvm_host.h

@@ -39,6 +39,7 @@
 #define EXIT_REASON_EXTERNAL_INTERRUPT	6
 #define EXIT_REASON_IPI			7
 #define EXIT_REASON_PTC_G		8
+#define EXIT_REASON_DEBUG		20
 
 /*Define vmm address space and vm data space.*/
 #define KVM_VMM_SIZE (__IA64_UL_CONST(16)<<20)
@@ -126,6 +127,8 @@
 			KVM_MEM_DIRTY_LOG_SIZE) / sizeof(struct kvm_vcpu_data)
 #define KVM_MAX_MEM_SIZE (KVM_P2M_SIZE >> 3 << PAGE_SHIFT)
 
+#define VMM_LOG_LEN 256
+
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/kvm.h>
@@ -437,6 +440,7 @@ struct kvm_vcpu_arch {
 
 	unsigned long opcode;
 	unsigned long cause;
+	char log_buf[VMM_LOG_LEN];
 	union context host;
 	union context guest;
 };

arch/ia64/kvm/Makefile

@@ -60,7 +60,7 @@ obj-$(CONFIG_KVM) += kvm.o
 
 CFLAGS_vcpu.o += -mfixed-range=f2-f5,f12-f127
 kvm-intel-objs = vmm.o vmm_ivt.o trampoline.o vcpu.o optvfault.o mmio.o \
-	vtlb.o process.o
+	vtlb.o process.o kvm_lib.o
 #Add link memcpy and memset to avoid possible structure assignment error
 kvm-intel-objs += memcpy.o memset.o
 obj-$(CONFIG_KVM_INTEL) += kvm-intel.o

arch/ia64/kvm/kvm-ia64.c

@@ -474,6 +474,13 @@ static int handle_external_interrupt(struct kvm_vcpu *vcpu,
 	return 1;
 }
 
+static int handle_vcpu_debug(struct kvm_vcpu *vcpu,
+				struct kvm_run *kvm_run)
+{
+	printk("VMM: %s", vcpu->arch.log_buf);
+	return 1;
+}
+
 static int (*kvm_vti_exit_handlers[])(struct kvm_vcpu *vcpu,
 		struct kvm_run *kvm_run) = {
 	[EXIT_REASON_VM_PANIC]              = handle_vm_error,
@@ -485,6 +492,7 @@ static int (*kvm_vti_exit_handlers[])(struct kvm_vcpu *vcpu,
 	[EXIT_REASON_EXTERNAL_INTERRUPT]    = handle_external_interrupt,
 	[EXIT_REASON_IPI]		    = handle_ipi,
 	[EXIT_REASON_PTC_G]		    = handle_global_purge,
+	[EXIT_REASON_DEBUG]		    = handle_vcpu_debug,
 
 };
 

arch/ia64/kvm/kvm_lib.c

@@ -0,0 +1,15 @@
+/*
+ * kvm_lib.c: Compile some libraries for kvm-intel module.
+ *
+ *	Just include kernel's library, and disable symbols export.
+ * 	Copyright (C) 2008, Intel Corporation.
+ *  	Xiantao Zhang  (xiantao.zhang@intel.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#undef CONFIG_MODULES
+#include "../../../lib/vsprintf.c"
+#include "../../../lib/ctype.c"

arch/ia64/kvm/vmm.c

@@ -62,5 +62,31 @@ void vmm_spin_unlock(spinlock_t *lock)
 {
 	_vmm_raw_spin_unlock(lock);
 }
+
+static void vcpu_debug_exit(struct kvm_vcpu *vcpu)
+{
+	struct exit_ctl_data *p = &vcpu->arch.exit_data;
+	long psr;
+
+	local_irq_save(psr);
+	p->exit_reason = EXIT_REASON_DEBUG;
+	vmm_transition(vcpu);
+	local_irq_restore(psr);
+}
+
+asmlinkage int printk(const char *fmt, ...)
+{
+	struct kvm_vcpu *vcpu = current_vcpu;
+	va_list args;
+	int r;
+
+	memset(vcpu->arch.log_buf, 0, VMM_LOG_LEN);
+	va_start(args, fmt);
+	r = vsnprintf(vcpu->arch.log_buf, VMM_LOG_LEN, fmt, args);
+	va_end(args);
+	vcpu_debug_exit(vcpu);
+	return r;
+}
+
 module_init(kvm_vmm_init)
 module_exit(kvm_vmm_exit)