[patch 1/4] KVM: basic paravirt support

[Marcelo Tosatti <mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

[-- Attachment #1: kvm-paravirt-core --]
[-- Type: text/plain, Size: 7119 bytes --]

Add basic KVM paravirt support. Avoid vm-exits on IO delays.

Add KVM_GET_PARA_FEATURES ioctl so paravirt features can be reported via
cpuid.

Signed-off-by: Marcelo Tosatti <mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

Index: linux-2.6-x86-kvm/arch/x86/Kconfig
===================================================================
--- linux-2.6-x86-kvm.orig/arch/x86/Kconfig
+++ linux-2.6-x86-kvm/arch/x86/Kconfig
@@ -357,6 +356,14 @@ config VMI
 	  at the moment), by linking the kernel to a GPL-ed ROM module
 	  provided by the hypervisor.
 
+config KVM_GUEST
+	bool "KVM Guest support"
+	select PARAVIRT
+	depends on !(X86_VISWS || X86_VOYAGER)
+	help
+	 This option enables various optimizations for running under the KVM
+	 hypervisor.
+
 source "arch/x86/lguest/Kconfig"
 
 endif
Index: linux-2.6-x86-kvm/arch/x86/kernel/Makefile
===================================================================
--- linux-2.6-x86-kvm.orig/arch/x86/kernel/Makefile
+++ linux-2.6-x86-kvm/arch/x86/kernel/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_K8_NB)		+= k8.o
 obj-$(CONFIG_MGEODE_LX)		+= geode_32.o mfgpt_32.o
 
 obj-$(CONFIG_VMI)		+= vmi_32.o vmiclock_32.o
+obj-$(CONFIG_KVM_GUEST)		+= kvm.o
 obj-$(CONFIG_PARAVIRT)		+= paravirt.o paravirt_patch_$(BITS).o
 obj-y				+= pcspeaker.o
 
Index: linux-2.6-x86-kvm/arch/x86/kernel/kvm.c
===================================================================
--- /dev/null
+++ linux-2.6-x86-kvm/arch/x86/kernel/kvm.c
@@ -0,0 +1,52 @@
+/*
+ * KVM paravirt_ops implementation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+ * Copyright IBM Corporation, 2007
+ *   Authors: Anthony Liguori <aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kvm_para.h>
+#include <linux/cpu.h>
+#include <linux/mm.h>
+
+/*
+ * No need for any "IO delay" on KVM
+ */
+static void kvm_io_delay(void)
+{
+}
+
+static void paravirt_ops_setup(void)
+{
+	pv_info.name = "KVM";
+	pv_info.paravirt_enabled = 1;
+
+	if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
+		pv_cpu_ops.io_delay = kvm_io_delay;
+
+}
+
+void __init kvm_guest_init(void)
+{
+	if (!kvm_para_available())
+		return;
+
+	paravirt_ops_setup();
+}
Index: linux-2.6-x86-kvm/arch/x86/kernel/setup_32.c
===================================================================
--- linux-2.6-x86-kvm.orig/arch/x86/kernel/setup_32.c
+++ linux-2.6-x86-kvm/arch/x86/kernel/setup_32.c
@@ -46,6 +46,7 @@
 #include <linux/pfn.h>
 #include <linux/pci.h>
 #include <linux/init_ohci1394_dma.h>
+#include <linux/kvm_para.h>
 
 #include <video/edid.h>
 
@@ -772,6 +773,7 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	vmi_init();
 #endif
+	kvm_guest_init();
 
 	/*
 	 * NOTE: before this point _nobody_ is allowed to allocate
Index: linux-2.6-x86-kvm/arch/x86/kernel/setup_64.c
===================================================================
--- linux-2.6-x86-kvm.orig/arch/x86/kernel/setup_64.c
+++ linux-2.6-x86-kvm/arch/x86/kernel/setup_64.c
@@ -42,6 +42,7 @@
 #include <linux/ctype.h>
 #include <linux/uaccess.h>
 #include <linux/init_ohci1394_dma.h>
+#include <linux/kvm_para.h>
 
 #include <asm/mtrr.h>
 #include <asm/uaccess.h>
@@ -506,6 +507,8 @@ void __init setup_arch(char **cmdline_p)
 	init_apic_mappings();
 	ioapic_init_mappings();
 
+	kvm_guest_init();
+
 	/*
 	 * We trust e820 completely. No explicit ROM probing in memory.
 	 */
Index: linux-2.6-x86-kvm/arch/x86/kvm/x86.c
===================================================================
--- linux-2.6-x86-kvm.orig/arch/x86/kvm/x86.c
+++ linux-2.6-x86-kvm/arch/x86/kvm/x86.c
@@ -680,6 +680,7 @@ int kvm_dev_ioctl_check_extension(long e
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_SET_TSS_ADDR:
 	case KVM_CAP_EXT_CPUID:
+	case KVM_CAP_PARA_FEATURES:
 		r = 1;
 		break;
 	case KVM_CAP_VAPIC:
@@ -727,6 +728,15 @@ long kvm_arch_dev_ioctl(struct file *fil
 		r = 0;
 		break;
 	}
+	case KVM_GET_PARA_FEATURES: {
+		__u32 para_features = KVM_PARA_FEATURES;
+
+		r = -EFAULT;
+		if (copy_to_user(argp, &para_features, sizeof para_features))
+			goto out;
+		r = 0;
+		break;
+	}
 	default:
 		r = -EINVAL;
 	}
Index: linux-2.6-x86-kvm/include/asm-x86/kvm_para.h
===================================================================
--- linux-2.6-x86-kvm.orig/include/asm-x86/kvm_para.h
+++ linux-2.6-x86-kvm/include/asm-x86/kvm_para.h
@@ -5,6 +5,7 @@
  * should be used to determine that a VM is running under KVM.
  */
 #define KVM_CPUID_SIGNATURE	0x40000000
+#define KVM_FEATURE_NOP_IO_DELAY	0
 
 /* This CPUID returns a feature bitmap in eax.  Before enabling a particular
  * paravirtualization, the appropriate feature bit should be checked.
@@ -14,6 +15,8 @@
 #ifdef __KERNEL__
 #include <asm/processor.h>
 
+#define KVM_PARA_FEATURES (1UL << KVM_FEATURE_NOP_IO_DELAY)
+
 /* This instruction is vmcall.  On non-VT architectures, it will generate a
  * trap that we will then rewrite to the appropriate instruction.
  */
Index: linux-2.6-x86-kvm/include/linux/kvm.h
===================================================================
--- linux-2.6-x86-kvm.orig/include/linux/kvm.h
+++ linux-2.6-x86-kvm/include/linux/kvm.h
@@ -221,6 +221,7 @@ struct kvm_vapic_addr {
  * Get size for mmap(vcpu_fd)
  */
 #define KVM_GET_VCPU_MMAP_SIZE    _IO(KVMIO,   0x04) /* in bytes */
+#define KVM_GET_PARA_FEATURES     _IOR(KVMIO,  0x05, __u32)
 
 /*
  * Extension capability list.
@@ -232,6 +233,7 @@ struct kvm_vapic_addr {
 #define KVM_CAP_SET_TSS_ADDR 4
 #define KVM_CAP_EXT_CPUID 5
 #define KVM_CAP_VAPIC 6
+#define KVM_CAP_PARA_FEATURES 7
 
 /*
  * ioctls for VM fds
Index: linux-2.6-x86-kvm/include/linux/kvm_para.h
===================================================================
--- linux-2.6-x86-kvm.orig/include/linux/kvm_para.h
+++ linux-2.6-x86-kvm/include/linux/kvm_para.h
@@ -20,6 +20,12 @@
 #include <asm/kvm_para.h>
 
 #ifdef __KERNEL__
+#ifdef CONFIG_KVM_GUEST
+void __init kvm_guest_init(void);
+#else
+#define kvm_guest_init() do { } while (0)
+#endif
+
 static inline int kvm_para_has_feature(unsigned int feature)
 {
 	if (kvm_arch_para_features() & (1UL << feature))

-- 


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