[PATCH v3 0/2] Xen HVM unplug changes

[PATCH v3 0/2] Xen HVM unplug changes

[Olaf Hering]

Update unplug in Xen HVM guests to cover more cases.
Please review.

changes in v3:
- adapt to API changes from 49137bf ("block-backend: remove blk_flush_all")

changes in v2:
- fix issues reported by checkpatch


Olaf Hering (2):
  xen_platform: unplug also SCSI disks
  xen_platform: SUSE xenlinux unplug for emulated PCI

 hw/i386/xen/xen_platform.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)


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[PATCH v3 1/2] xen_platform: unplug also SCSI disks

[Olaf Hering]

Using 'vdev=sd[a-o]' will create an emulated LSI controller, which can
be used by the emulated BIOS to boot from disk. If the HVM domU has also
PV driver the disk may appear twice in the guest. To avoid this an
unplug of the emulated hardware is needed, similar to what is done for
IDE and NIC drivers already.

Since the SCSI controller provides only disks the entire controller can
be unplugged at once.

Impact of the change for classic and pvops based guest kernels:

 vdev=sda:disk0
before: pvops:   disk0=pv xvda + emulated sda
        classic: disk0=pv sda  + emulated sdq
after:  pvops:   disk0=pv xvda
        classic: disk0=pv sda

 vdev=hda:disk0, vdev=sda:disk1
before: pvops:   disk0=pv xvda
                 disk1=emulated sda
        classic: disk0=pv hda
                 disk1=pv sda  + emulated sdq
after:  pvops:   disk0=pv xvda
                 disk1=not accessible by blkfront, index hda==index sda
        classic: disk0=pv hda
                 disk1=pv sda

 vdev=hda:disk0, vdev=sda:disk1, vdev=sdb:disk2
before: pvops:   disk0=pv xvda
                 disk1=emulated sda
                 disk2=pv xvdb + emulated sdb
        classic: disk0=pv hda
                 disk1=pv sda  + emulated sdq
                 disk2=pv sdb  + emulated sdr
after:  pvops:   disk0=pv xvda
                 disk1=not accessible by blkfront, index hda==index sda
                 disk2=pv xvdb
        classic: disk0=pv hda
                 disk1=pv sda
                 disk2=pv sda

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 hw/i386/xen/xen_platform.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
index f85635c..91d8a7a 100644
--- a/hw/i386/xen/xen_platform.c
+++ b/hw/i386/xen/xen_platform.c
@@ -114,6 +114,10 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void *o)
             PCI_CLASS_STORAGE_IDE
             && strcmp(d->name, "xen-pci-passthrough") != 0) {
         pci_piix3_xen_ide_unplug(DEVICE(d));
+    } else if (pci_get_word(d->config + PCI_CLASS_DEVICE) ==
+            PCI_CLASS_STORAGE_SCSI
+            && strcmp(d->name, "xen-pci-passthrough") != 0) {
+        object_unparent(OBJECT(d));
     }
 }
 

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Re: [PATCH v3 1/2] xen_platform: unplug also SCSI disks

[Stefano Stabellini]

On Fri, 21 Oct 2016, Olaf Hering wrote:
> Using 'vdev=sd[a-o]' will create an emulated LSI controller, which can
> be used by the emulated BIOS to boot from disk. If the HVM domU has also
> PV driver the disk may appear twice in the guest. To avoid this an
> unplug of the emulated hardware is needed, similar to what is done for
> IDE and NIC drivers already.
> 
> Since the SCSI controller provides only disks the entire controller can
> be unplugged at once.
> 
> Impact of the change for classic and pvops based guest kernels:
> 
>  vdev=sda:disk0
> before: pvops:   disk0=pv xvda + emulated sda
>         classic: disk0=pv sda  + emulated sdq
> after:  pvops:   disk0=pv xvda
>         classic: disk0=pv sda
> 
>  vdev=hda:disk0, vdev=sda:disk1
> before: pvops:   disk0=pv xvda
>                  disk1=emulated sda
>         classic: disk0=pv hda
>                  disk1=pv sda  + emulated sdq
> after:  pvops:   disk0=pv xvda
>                  disk1=not accessible by blkfront, index hda==index sda
>         classic: disk0=pv hda
>                  disk1=pv sda
> 
>  vdev=hda:disk0, vdev=sda:disk1, vdev=sdb:disk2
> before: pvops:   disk0=pv xvda
>                  disk1=emulated sda
>                  disk2=pv xvdb + emulated sdb
>         classic: disk0=pv hda
>                  disk1=pv sda  + emulated sdq
>                  disk2=pv sdb  + emulated sdr
> after:  pvops:   disk0=pv xvda
>                  disk1=not accessible by blkfront, index hda==index sda
>                  disk2=pv xvdb
>         classic: disk0=pv hda
>                  disk1=pv sda
>                  disk2=pv sda
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


>  hw/i386/xen/xen_platform.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
> index f85635c..91d8a7a 100644
> --- a/hw/i386/xen/xen_platform.c
> +++ b/hw/i386/xen/xen_platform.c
> @@ -114,6 +114,10 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void *o)
>              PCI_CLASS_STORAGE_IDE
>              && strcmp(d->name, "xen-pci-passthrough") != 0) {
>          pci_piix3_xen_ide_unplug(DEVICE(d));
> +    } else if (pci_get_word(d->config + PCI_CLASS_DEVICE) ==
> +            PCI_CLASS_STORAGE_SCSI
> +            && strcmp(d->name, "xen-pci-passthrough") != 0) {
> +        object_unparent(OBJECT(d));
>      }
>  }
>  
> 

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Re: [PATCH v3 1/2] xen_platform: unplug also SCSI disks

[Olaf Hering]

[-- Attachment #1.1: Type: text/plain, Size: 671 bytes --]

On Fri, Oct 21, Olaf Hering wrote:

> Using 'vdev=sd[a-o]' will create an emulated LSI controller, which can
> be used by the emulated BIOS to boot from disk. If the HVM domU has also
> PV driver the disk may appear twice in the guest. To avoid this an
> unplug of the emulated hardware is needed, similar to what is done for
> IDE and NIC drivers already.

How are these patches supposed to find their way into
qemu-xen.git#staging? Do I have to wait until #staging gets updated to
qemu-2.8+ at some point, or would you please cherry-pick these two commits:

3513201 xen_platform: SUSE xenlinux unplug for emulated PCI
78f6689 xen_platform: unplug also SCSI disks

Olaf

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Re: [PATCH v3 1/2] xen_platform: unplug also SCSI disks

[Stefano Stabellini]

On Thu, 24 Nov 2016, Olaf Hering wrote:
> On Fri, Oct 21, Olaf Hering wrote:
> 
> > Using 'vdev=sd[a-o]' will create an emulated LSI controller, which can
> > be used by the emulated BIOS to boot from disk. If the HVM domU has also
> > PV driver the disk may appear twice in the guest. To avoid this an
> > unplug of the emulated hardware is needed, similar to what is done for
> > IDE and NIC drivers already.
> 
> How are these patches supposed to find their way into
> qemu-xen.git#staging? Do I have to wait until #staging gets updated to
> qemu-2.8+ at some point, or would you please cherry-pick these two commits:
> 
> 3513201 xen_platform: SUSE xenlinux unplug for emulated PCI
> 78f6689 xen_platform: unplug also SCSI disks

Anthony, are you going to take care of this?
However, given the state of the release, they'll need a release-ack to
be applied.

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Re: [PATCH v3 1/2] xen_platform: unplug also SCSI disks

[Wei Liu]

On Mon, Nov 28, 2016 at 10:28:21AM -0800, Stefano Stabellini wrote:
> On Thu, 24 Nov 2016, Olaf Hering wrote:
> > On Fri, Oct 21, Olaf Hering wrote:
> > 
> > > Using 'vdev=sd[a-o]' will create an emulated LSI controller, which can
> > > be used by the emulated BIOS to boot from disk. If the HVM domU has also
> > > PV driver the disk may appear twice in the guest. To avoid this an
> > > unplug of the emulated hardware is needed, similar to what is done for
> > > IDE and NIC drivers already.
> > 
> > How are these patches supposed to find their way into
> > qemu-xen.git#staging? Do I have to wait until #staging gets updated to
> > qemu-2.8+ at some point, or would you please cherry-pick these two commits:
> > 
> > 3513201 xen_platform: SUSE xenlinux unplug for emulated PCI
> > 78f6689 xen_platform: unplug also SCSI disks
> 
> Anthony, are you going to take care of this?
> However, given the state of the release, they'll need a release-ack to
> be applied.

I think these patches will need to wait to be backported after 4.8 is
released.

Wei.

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Re: [PATCH v3 1/2] xen_platform: unplug also SCSI disks

[Olaf Hering]

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On Tue, Nov 29, Wei Liu wrote:

> On Mon, Nov 28, 2016 at 10:28:21AM -0800, Stefano Stabellini wrote:
> > Anthony, are you going to take care of this?
> > However, given the state of the release, they'll need a release-ack to
> > be applied.
> I think these patches will need to wait to be backported after 4.8 is
> released.

Also this patch should be backported to every tree containing qemu-2.1+:
"xen_disk: split discard input to match internal representation"

Olaf

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[PATCH v3 2/2] xen_platform: SUSE xenlinux unplug for emulated PCI

[Olaf Hering]

Implement SUSE specific unplug protocol for emulated PCI devices
in PVonHVM guests. Its a simple 'outl(1, (ioaddr + 4));'.
This protocol was implemented and used since Xen 3.0.4.
It is used in all SUSE/SLES/openSUSE releases up to SLES11SP3 and
openSUSE 12.3.
In addition old (pre-2011) VMDP versions are handled as well.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 hw/i386/xen/xen_platform.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
index 91d8a7a..2e1e543 100644
--- a/hw/i386/xen/xen_platform.c
+++ b/hw/i386/xen/xen_platform.c
@@ -311,13 +311,38 @@ static void xen_platform_ioport_writeb(void *opaque, hwaddr addr,
                                        uint64_t val, unsigned int size)
 {
     PCIXenPlatformState *s = opaque;
+    PCIDevice *pci_dev = PCI_DEVICE(s);
 
     switch (addr) {
     case 0: /* Platform flags */
         platform_fixed_ioport_writeb(opaque, 0, (uint32_t)val);
         break;
+    case 4:
+        if (val == 1) {
+            /*
+             * SUSE unplug for Xenlinux
+             * xen-kmp used this since xen-3.0.4, instead the official protocol
+             * from xen-3.3+ It did an unconditional "outl(1, (ioaddr + 4));"
+             * Pre VMDP 1.7 used 4 and 8 depending on how VMDP was configured.
+             * If VMDP was to control both disk and LAN it would use 4.
+             * If it controlled just disk or just LAN, it would use 8 below.
+             */
+            pci_unplug_disks(pci_dev->bus);
+            pci_unplug_nics(pci_dev->bus);
+        }
+        break;
     case 8:
-        log_writeb(s, (uint32_t)val);
+        switch (val) {
+        case 1:
+            pci_unplug_disks(pci_dev->bus);
+            break;
+        case 2:
+            pci_unplug_nics(pci_dev->bus);
+            break;
+        default:
+            log_writeb(s, (uint32_t)val);
+            break;
+        }
         break;
     default:
         break;

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Re: [PATCH v3 2/2] xen_platform: SUSE xenlinux unplug for emulated PCI

[Stefano Stabellini]

On Fri, 21 Oct 2016, Olaf Hering wrote:
> Implement SUSE specific unplug protocol for emulated PCI devices
> in PVonHVM guests. Its a simple 'outl(1, (ioaddr + 4));'.
> This protocol was implemented and used since Xen 3.0.4.
> It is used in all SUSE/SLES/openSUSE releases up to SLES11SP3 and
> openSUSE 12.3.
> In addition old (pre-2011) VMDP versions are handled as well.
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


>  hw/i386/xen/xen_platform.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
> index 91d8a7a..2e1e543 100644
> --- a/hw/i386/xen/xen_platform.c
> +++ b/hw/i386/xen/xen_platform.c
> @@ -311,13 +311,38 @@ static void xen_platform_ioport_writeb(void *opaque, hwaddr addr,
>                                         uint64_t val, unsigned int size)
>  {
>      PCIXenPlatformState *s = opaque;
> +    PCIDevice *pci_dev = PCI_DEVICE(s);
>  
>      switch (addr) {
>      case 0: /* Platform flags */
>          platform_fixed_ioport_writeb(opaque, 0, (uint32_t)val);
>          break;
> +    case 4:
> +        if (val == 1) {
> +            /*
> +             * SUSE unplug for Xenlinux
> +             * xen-kmp used this since xen-3.0.4, instead the official protocol
> +             * from xen-3.3+ It did an unconditional "outl(1, (ioaddr + 4));"
> +             * Pre VMDP 1.7 used 4 and 8 depending on how VMDP was configured.
> +             * If VMDP was to control both disk and LAN it would use 4.
> +             * If it controlled just disk or just LAN, it would use 8 below.
> +             */
> +            pci_unplug_disks(pci_dev->bus);
> +            pci_unplug_nics(pci_dev->bus);
> +        }
> +        break;
>      case 8:
> -        log_writeb(s, (uint32_t)val);
> +        switch (val) {
> +        case 1:
> +            pci_unplug_disks(pci_dev->bus);
> +            break;
> +        case 2:
> +            pci_unplug_nics(pci_dev->bus);
> +            break;
> +        default:
> +            log_writeb(s, (uint32_t)val);
> +            break;
> +        }
>          break;
>      default:
>          break;
> 

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