From 9c3b9ce8260ffc476f7539cc683e7efe59eba979 Mon Sep 17 00:00:00 2001
Message-Id: <9c3b9ce8260ffc476f7539cc683e7efe59eba979.1380112457.git.jdenemar@redhat.com>
From: Laine Stump <laine@laine.org>
Date: Fri, 20 Sep 2013 05:16:21 -0600
Subject: [PATCH] qemu: use "ide" as device name for implicit SATA controller
 on Q35

This resolves https://bugzilla.redhat.com/show_bug.cgi?id=1008903

The Q35 machinetype has an implicit SATA controller at 00:1F.2 which
isn't given the "expected" id of ahci0 by qemu when it's created. The
original suggested solution to this problem was to not specify any
controller for the disks that use the default controller and just
specify "unit=n" instead; qemu should then use the first IDE or SATA
controller for the disk.

Unfortunately, this "solution" is ignorant of the fact that in the
case of SATA disks, the "unit" attribute in the disk XML is actually
*not* being used for the unit, but is instead used to specify the
"bus" number; each SATA controller has 6 buses, and each bus only
allows a single unit. This makes it nonsensical to specify unit='n'
where n is anything other than 0. It also means that the only way to
connect more than a single device to the implicit SATA controller is
to explicitly give the bus names, which happen to be "ide.$n", where
$n can be replaced by the disk's "unit" number.

(cherry picked from commit 30bb4c4b54ed3a23adc90c52540dd96b0cbcfbcc)

Conflicts:

tests/qemuxml2argvdata/qemuxml2argv-pcihole64-q35.args - this upstream
file didn't yet exist in the libvirt release used as the base for the
RHEL7 build.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/qemu/qemu_command.c                      | 15 ++++++---------
 tests/qemuxml2argvdata/qemuxml2argv-q35.args |  2 +-
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 6e9657f..6a6b3cd 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -4280,18 +4280,15 @@ qemuBuildDriveDevStr(virDomainDefPtr def,
         if (qemuDomainMachineIsQ35(def) &&
             disk->info.addr.drive.controller == 0) {
             /* Q35 machines have an implicit ahci (sata) controller at
-             * 00:1F.2 which has no "id" associated with it. For this
-             * reason, we can't refer to it as "ahci0". Instead, we
-             * don't give an id, which qemu interprets as "use the
-             * first ahci controller". We then need to specify the
-             * unit with "unit=%d" rather than adding it onto the bus
-             * arg.
+             * 00:1F.2 which for some reason is hardcoded with the id
+             * "ide" instead of the seemingly more reasonable "ahci0"
+             * or "sata0".
              */
-            virBufferAsprintf(&opt, ",unit=%d", disk->info.addr.drive.unit);
+            virBufferAsprintf(&opt, ",bus=ide.%d", disk->info.addr.drive.unit);
         } else {
             /* All other ahci controllers have been created by
-             * libvirt, so they *do* have an id, and we can identify
-             * them that way.
+             * libvirt, and we gave them the id "ahci${n}" where ${n}
+             * is the controller number. So we identify them that way.
              */
             virBufferAsprintf(&opt, ",bus=ahci%d.%d",
                               disk->info.addr.drive.controller,
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-q35.args b/tests/qemuxml2argvdata/qemuxml2argv-q35.args
index 9e67be5..151863e 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-q35.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-q35.args
@@ -4,5 +4,5 @@ LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test \
 -device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x2 \
 -device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x1 \
 -drive file=/dev/HostVG/QEMUGuest1,if=none,id=drive-sata0-0-0 \
--device ide-drive,unit=0,drive=drive-sata0-0-0,id=sata0-0-0 \
+-device ide-drive,bus=ide.0,drive=drive-sata0-0-0,id=sata0-0-0 \
 -vga qxl -global qxl.ram_size=67108864 -global qxl.vram_size=18874368
-- 
1.8.3.2