[libvirt] [PATCH] Clarify lack of generated IDE -device string in QEMU driver

2010-01-28 Thread Matthew Booth 
The QEMU driver contained code to generate a -device string for piix4-ide, but
wasn't using it. This was intentional. This change removes the string generation
and adds a comment explaining why no -device is necessary.

* src/qemu/qemu_conf.c: Remove VIR_DOMAIN_CONTROLLER_TYPE_IDE handler in
qemuBuildControllerDevStr(). Add comments.
---
 src/qemu/qemu_conf.c |   16 
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index f4a6c08..1c4f326 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -2121,11 +2121,8 @@ qemuBuildControllerDevStr(virDomainControllerDefPtr def)
 virBufferVSprintf(buf, ,id=scsi%d, def-idx);
 break;
 
+/* We always get an IDE controller, whether we want it or not. */
 case VIR_DOMAIN_CONTROLLER_TYPE_IDE:
-virBufferAddLit(buf, piix4-ide);
-virBufferVSprintf(buf, ,id=ide%d, def-idx);
-break;
-
 default:
 goto error;
 }
@@ -3141,16 +3138,19 @@ int qemudBuildCommandLine(virConnectPtr conn,
 
 if (qemuCmdFlags  QEMUD_CMD_FLAG_DEVICE) {
 for (i = 0 ; i  def-ncontrollers ; i++) {
-char *scsi;
-if (def-controllers[i]-type != VIR_DOMAIN_CONTROLLER_TYPE_SCSI)
+/* We don't add an explicit IDE controller because the provided
+ * PIIX4 device already includes one. It isn't possible to remove
+ * the PIIX4. */
+if (def-controllers[i]-type == VIR_DOMAIN_CONTROLLER_TYPE_IDE)
 continue;
 
 ADD_ARG_LIT(-device);
 
-if (!(scsi = qemuBuildControllerDevStr(def-controllers[i])))
+char *devstr;
+if (!(devstr = qemuBuildControllerDevStr(def-controllers[i])))
 goto no_memory;
 
-ADD_ARG(scsi);
+ADD_ARG(devstr);
 }
 }
 
-- 
1.6.6

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Re: [libvirt] [PATCH] Clarify lack of generated IDE -device string in QEMU driver

2010-01-28 Thread Daniel P. Berrange 
On Thu, Jan 28, 2010 at 10:35:48AM +, Matthew Booth wrote:
 The QEMU driver contained code to generate a -device string for piix4-ide, but
 wasn't using it. This was intentional. This change removes the string 
 generation
 and adds a comment explaining why no -device is necessary.
 
 * src/qemu/qemu_conf.c: Remove VIR_DOMAIN_CONTROLLER_TYPE_IDE handler in
 qemuBuildControllerDevStr(). Add comments.
 ---
  src/qemu/qemu_conf.c |   16 
  1 files changed, 8 insertions(+), 8 deletions(-)
 
 diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
 index f4a6c08..1c4f326 100644
 --- a/src/qemu/qemu_conf.c
 +++ b/src/qemu/qemu_conf.c
 @@ -2121,11 +2121,8 @@ qemuBuildControllerDevStr(virDomainControllerDefPtr 
 def)
  virBufferVSprintf(buf, ,id=scsi%d, def-idx);
  break;
  
 +/* We always get an IDE controller, whether we want it or not. */
  case VIR_DOMAIN_CONTROLLER_TYPE_IDE:
 -virBufferAddLit(buf, piix4-ide);
 -virBufferVSprintf(buf, ,id=ide%d, def-idx);
 -break;
 -
  default:
  goto error;
  }
 @@ -3141,16 +3138,19 @@ int qemudBuildCommandLine(virConnectPtr conn,
  
  if (qemuCmdFlags  QEMUD_CMD_FLAG_DEVICE) {
  for (i = 0 ; i  def-ncontrollers ; i++) {
 -char *scsi;
 -if (def-controllers[i]-type != VIR_DOMAIN_CONTROLLER_TYPE_SCSI)
 +/* We don't add an explicit IDE controller because the provided
 + * PIIX4 device already includes one. It isn't possible to remove
 + * the PIIX4. */
 +if (def-controllers[i]-type == VIR_DOMAIN_CONTROLLER_TYPE_IDE)
  continue;

That's not quite right because you changed the conditional to blacklist IDE
insteasd of whitelisting SCSI. This means that FDC now falls through. We do
not need to explicitly add the FDC, since that is also provided automatically
on the ISA bridge that's behind the PIIX4.

  
  ADD_ARG_LIT(-device);
  
 -if (!(scsi = qemuBuildControllerDevStr(def-controllers[i])))
 +char *devstr;
 +if (!(devstr = qemuBuildControllerDevStr(def-controllers[i])))
  goto no_memory;
  
 -ADD_ARG(scsi);
 +ADD_ARG(devstr);
  }
  }
  

Daniel
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Re: [libvirt] [PATCH] Clarify lack of generated IDE -device string in QEMU driver

2010-01-28 Thread Matthew Booth 
On 28/01/10 10:57, Daniel P. Berrange wrote:
 On Thu, Jan 28, 2010 at 10:35:48AM +, Matthew Booth wrote:
 The QEMU driver contained code to generate a -device string for piix4-ide, 
 but
 wasn't using it. This was intentional. This change removes the string 
 generation
 and adds a comment explaining why no -device is necessary.

 * src/qemu/qemu_conf.c: Remove VIR_DOMAIN_CONTROLLER_TYPE_IDE handler in
 qemuBuildControllerDevStr(). Add comments.
 ---
  src/qemu/qemu_conf.c |   16 
  1 files changed, 8 insertions(+), 8 deletions(-)

 diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
 index f4a6c08..1c4f326 100644
 --- a/src/qemu/qemu_conf.c
 +++ b/src/qemu/qemu_conf.c
 @@ -2121,11 +2121,8 @@ qemuBuildControllerDevStr(virDomainControllerDefPtr 
 def)
  virBufferVSprintf(buf, ,id=scsi%d, def-idx);
  break;
  
 +/* We always get an IDE controller, whether we want it or not. */
  case VIR_DOMAIN_CONTROLLER_TYPE_IDE:
 -virBufferAddLit(buf, piix4-ide);
 -virBufferVSprintf(buf, ,id=ide%d, def-idx);
 -break;
 -
  default:
  goto error;
  }
 @@ -3141,16 +3138,19 @@ int qemudBuildCommandLine(virConnectPtr conn,
  
  if (qemuCmdFlags  QEMUD_CMD_FLAG_DEVICE) {
  for (i = 0 ; i  def-ncontrollers ; i++) {
 -char *scsi;
 -if (def-controllers[i]-type != 
 VIR_DOMAIN_CONTROLLER_TYPE_SCSI)
 +/* We don't add an explicit IDE controller because the provided
 + * PIIX4 device already includes one. It isn't possible to 
 remove
 + * the PIIX4. */
 +if (def-controllers[i]-type == VIR_DOMAIN_CONTROLLER_TYPE_IDE)
  continue;
 
 That's not quite right because you changed the conditional to blacklist IDE
 insteasd of whitelisting SCSI. This means that FDC now falls through. We do
 not need to explicitly add the FDC, since that is also provided automatically
 on the ISA bridge that's behind the PIIX4.

Ok. Still think a blacklist is more appropriate, though. I'll add FDC to
the blacklist. Are there any more?

Matt
-- 
Matthew Booth, RHCA, RHCSS
Red Hat Engineering, Virtualisation Team

M:   +44 (0)7977 267231
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