From 75ea7130586243c500d6e27d26942facf516226f Mon Sep 17 00:00:00 2001

From: "Richard W.M. Jones" <rjones@redhat.com>

Date: Wed, 14 Aug 2013 15:08:04 +0100

Subject: [PATCH] launch: direct: Don't use -cpu host on TCG.

qemu -cpu \? documents this as:

host  KVM processor with all supported host features (only available in KVM mode)

And indeed if you try it with TCG you'll get this error:

Unable to find CPU definition: host

This fixes commit 038ed0a08eaed33e62a27c9f91780a25de0bc08c.

(cherry picked from commit c53b459fdd7fc340f48a76496b7e7e18256a2d64)

---

 src/launch-direct.c | 39 ++++++++++++++++++++++++++-------------

 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/src/launch-direct.c b/src/launch-direct.c

index 90d0df9..299a3d9 100644

--- a/src/launch-direct.c

+++ b/src/launch-direct.c

@@ -20,6 +20,7 @@

 #include <stdio.h>

 #include <stdlib.h>

+#include <stdbool.h>

 #include <stdint.h>

 #include <inttypes.h>

 #include <unistd.h>

@@ -258,6 +259,7 @@ launch_direct (guestfs_h *g, const char *arg)

     char buf[256];

     int virtio_scsi = qemu_supports_virtio_scsi (g);

     struct qemu_param *qp;

+    bool has_kvm;

     /* Set up the full command line.  Do this in the subprocess so we

      * don't need to worry about cleaning up.

@@ -290,6 +292,14 @@ launch_direct (guestfs_h *g, const char *arg)

     add_cmdline (g, "-nographic");

+    /* Try to guess if KVM is available.  We are just checking that

+     * /dev/kvm is openable.  That's not reliable, since /dev/kvm

+     * might be openable by qemu but not by us (think: SELinux) in

+     * which case the user would not get hardware virtualization,

+     * although at least shouldn't fail.

+     */

+    has_kvm = is_openable (g, "/dev/kvm", O_RDWR|O_CLOEXEC);

+

     /* The qemu -machine option (added 2010-12) is a bit more sane

      * since it falls back through various different acceleration

      * modes, so try that first (thanks Markus Armbruster).

@@ -301,23 +311,26 @@ launch_direct (guestfs_h *g, const char *arg)

       /* qemu sometimes needs this option to enable hardware

        * virtualization, but some versions of 'qemu-kvm' will use KVM

        * regardless (even where this option appears in the help text).

-       * It is rumoured that there are versions of qemu where supplying

-       * this option when hardware virtualization is not available will

-       * cause qemu to fail, so we we have to check at least that

-       * /dev/kvm is openable.  That's not reliable, since /dev/kvm

-       * might be openable by qemu but not by us (think: SELinux) in

-       * which case the user would not get hardware virtualization,

-       * although at least shouldn't fail.  A giant clusterfuck with the

-       * qemu command line, again.

+       * It is rumoured that there are versions of qemu where

+       * supplying this option when hardware virtualization is not

+       * available will cause qemu to fail.  A giant clusterfuck with

+       * the qemu command line, again.

        */

-      if (qemu_supports (g, "-enable-kvm") &&

-          is_openable (g, "/dev/kvm", O_RDWR|O_CLOEXEC))

+      if (qemu_supports (g, "-enable-kvm") && has_kvm)

         add_cmdline (g, "-enable-kvm");

     }

-    /* Specify the host CPU for speed, and kvmclock for stability. */

-    add_cmdline (g, "-cpu");

-    add_cmdline (g, "host,+kvmclock");

+    /* -cpu host only works if KVM is available. */

+    if (has_kvm) {

+      /* Specify the host CPU for speed, and kvmclock for stability. */

+      add_cmdline (g, "-cpu");

+      add_cmdline (g, "host,+kvmclock");

+    } else {

+      /* Specify default CPU for speed, and kvmclock for stability. */

+      snprintf (buf, sizeof buf, "qemu%d,+kvmclock", SIZEOF_LONG*8);

+      add_cmdline (g, "-cpu");

+      add_cmdline (g, buf);

+    }

     if (g->smp > 1) {

       snprintf (buf, sizeof buf, "%d", g->smp);

-- 

1.8.3.1