Add KVM support to QEMU

This patch adds very basic KVM support.  KVM is a kernel module for Linux that
allows userspace programs to make use of hardware virtualization support.  It
current supports x86 hardware virtualization using Intel VT-x or AMD-V.  It
also supports IA64 VT-i, PPC 440, and S390.

This patch only implements the bare minimum support to get a guest booting.  It
has very little impact the rest of QEMU and attempts to integrate nicely with
the rest of QEMU.

Even though this implementation is basic, it is significantly faster than TCG.
Booting and shutting down a Linux guest:

w/TCG:  1:32.36 elapsed  84% CPU

w/KVM:  0:31.14 elapsed  59% CPU

Right now, KVM is disabled by default and must be explicitly enabled with
 -enable-kvm.  We can enable it by default later when we have had better
testing.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5627 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 34 insertions, 0 deletions

diff --git a/vl.c b/vl.c
index ee93c73087..ea9e6529e9 100644
--- a/vl.c
+++ b/vl.c
@@ -39,6 +39,7 @@
 #include "block.h"
 #include "audio/audio.h"
 #include "migration.h"
+#include "kvm.h"
 
 #include <unistd.h>
 #include <fcntl.h>
@@ -4782,6 +4783,9 @@ static void help(int exitcode)
            "-kernel-kqemu   enable KQEMU full virtualization (default is user mode only)\n"
            "-no-kqemu       disable KQEMU kernel module usage\n"
 #endif
+#ifdef CONFIG_KVM
+           "-enable-kvm     enable KVM full virtualization support\n"
+#endif
 #ifdef TARGET_I386
            "-no-acpi        disable ACPI\n"
 #endif
@@ -4887,6 +4891,7 @@ enum {
     QEMU_OPTION_pidfile,
     QEMU_OPTION_no_kqemu,
     QEMU_OPTION_kernel_kqemu,
+    QEMU_OPTION_enable_kvm,
     QEMU_OPTION_win2k_hack,
     QEMU_OPTION_usb,
     QEMU_OPTION_usbdevice,
@@ -4973,6 +4978,9 @@ static const QEMUOption qemu_options[] = {
     { "no-kqemu", 0, QEMU_OPTION_no_kqemu },
     { "kernel-kqemu", 0, QEMU_OPTION_kernel_kqemu },
 #endif
+#ifdef CONFIG_KVM
+    { "enable-kvm", 0, QEMU_OPTION_enable_kvm },
+#endif
 #if defined(TARGET_PPC) || defined(TARGET_SPARC)
     { "g", 1, QEMU_OPTION_g },
 #endif
@@ -5794,6 +5802,14 @@ int main(int argc, char **argv)
                 kqemu_allowed = 2;
                 break;
 #endif
+#ifdef CONFIG_KVM
+            case QEMU_OPTION_enable_kvm:
+                kvm_allowed = 1;
+#ifdef USE_KQEMU
+                kqemu_allowed = 0;
+#endif
+                break;
+#endif
             case QEMU_OPTION_usb:
                 usb_enabled = 1;
                 break;
@@ -5928,6 +5944,14 @@ int main(int argc, char **argv)
         }
     }
 
+#if defined(CONFIG_KVM) && defined(USE_KQEMU)
+    if (kvm_allowed && kqemu_allowed) {
+        fprintf(stderr,
+                "You can not enable both KVM and kqemu at the same time\n");
+        exit(1);
+    }
+#endif
+
     machine->max_cpus = machine->max_cpus ?: 1; /* Default to UP */
     if (smp_cpus > machine->max_cpus) {
         fprintf(stderr, "Number of SMP cpus requested (%d), exceeds max cpus "
@@ -6229,6 +6253,16 @@ int main(int argc, char **argv)
         }
     }
 
+    if (kvm_enabled()) {
+        int ret;
+
+        ret = kvm_init(smp_cpus);
+        if (ret < 0) {
+            fprintf(stderr, "failed to initialize KVM\n");
+            exit(1);
+        }
+    }
+
     machine->init(ram_size, vga_ram_size, boot_devices, ds,
                   kernel_filename, kernel_cmdline, initrd_filename, cpu_model);