[Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Michael S. Tsirkin]

xenfv has no fwcfg and so does not load acpi from QEMU.
as such new acpi features don't work.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

Sander, could you pleas econfirm this works for you?
Also, Xen really should switch to fw cfg some day ...

 hw/i386/pc_piix.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index a327d71..1acd2b2 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -793,6 +793,17 @@ static QEMUMachine xenfv_machine = {
     .max_cpus = HVM_MAX_VCPUS,
     .default_machine_opts = "accel=xen",
     .hot_add_cpu = pc_hot_add_cpu,
+    .compat_props = (GlobalProperty[]) {
+        /* xenfv has no fwcfg and so does not load acpi from QEMU.
+         * as such new acpi features don't work.
+         */
+        {
+            .driver   = "PIIX4_PM",
+            .property = "acpi-pci-hotplug-with-bridge-support",
+            .value    = "off",
+        },
+        { /* end of list */ }
+    },
 };
 #endif
 
-- 
MST

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Paolo Bonzini]

Il 04/02/2014 22:32, Michael S. Tsirkin ha scritto:
> xenfv has no fwcfg and so does not load acpi from QEMU.
> as such new acpi features don't work.
>
> Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>
> Sander, could you pleas econfirm this works for you?
> Also, Xen really should switch to fw cfg some day ...

Yeah, especially because nowadays "-M pc" works with Xen.  It would be 
nice if fw_cfg could be enabled even for Xen on all machines except the 
legacy "-M xenfv".

Stefano, could you give it a shot now that you'll be soon done with 4.4?

Paolo

>  hw/i386/pc_piix.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index a327d71..1acd2b2 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -793,6 +793,17 @@ static QEMUMachine xenfv_machine = {
>      .max_cpus = HVM_MAX_VCPUS,
>      .default_machine_opts = "accel=xen",
>      .hot_add_cpu = pc_hot_add_cpu,
> +    .compat_props = (GlobalProperty[]) {
> +        /* xenfv has no fwcfg and so does not load acpi from QEMU.
> +         * as such new acpi features don't work.
> +         */
> +        {
> +            .driver   = "PIIX4_PM",
> +            .property = "acpi-pci-hotplug-with-bridge-support",
> +            .value    = "off",
> +        },
> +        { /* end of list */ }
> +    },
>  };
>  #endif
>
>

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Sander Eikelenboom]

Tuesday, February 4, 2014, 10:55:18 PM, you wrote:

> Il 04/02/2014 22:32, Michael S. Tsirkin ha scritto:
>> xenfv has no fwcfg and so does not load acpi from QEMU.
>> as such new acpi features don't work.
>>
>> Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
>> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>> ---
>>
>> Sander, could you pleas econfirm this works for you?

Yes this works for me (still on top of the debug patches + pull of the branch igor mentoined),
but without -global PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off:

No fw cfg. Bailing out.
bsel: 0, bus: pci.0
bsel: 0, bus: pci.0
bsel: 0, bus: pci.0
bsel: 0, bus: pci.0

Thanks !
--
Sander

>> Also, Xen really should switch to fw cfg some day ...

> Yeah, especially because nowadays "-M pc" works with Xen.  It would be 
> nice if fw_cfg could be enabled even for Xen on all machines except the 
> legacy "-M xenfv".

> Stefano, could you give it a shot now that you'll be soon done with 4.4?

> Paolo

>>  hw/i386/pc_piix.c | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>>
>> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>> index a327d71..1acd2b2 100644
>> --- a/hw/i386/pc_piix.c
>> +++ b/hw/i386/pc_piix.c
>> @@ -793,6 +793,17 @@ static QEMUMachine xenfv_machine = {
>>      .max_cpus = HVM_MAX_VCPUS,
>>      .default_machine_opts = "accel=xen",
>>      .hot_add_cpu = pc_hot_add_cpu,
>> +    .compat_props = (GlobalProperty[]) {
>> +        /* xenfv has no fwcfg and so does not load acpi from QEMU.
>> +         * as such new acpi features don't work.
>> +         */
>> +        {
>> +            .driver   = "PIIX4_PM",
>> +            .property = "acpi-pci-hotplug-with-bridge-support",
>> +            .value    = "off",
>> +        },
>> +        { /* end of list */ }
>> +    },
>>  };
>>  #endif
>>
>>

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Stefano Stabellini]

On Tue, 4 Feb 2014, Sander Eikelenboom wrote:
> Tuesday, February 4, 2014, 10:55:18 PM, you wrote:
> 
> > Il 04/02/2014 22:32, Michael S. Tsirkin ha scritto:
> >> xenfv has no fwcfg and so does not load acpi from QEMU.
> >> as such new acpi features don't work.
> >>
> >> Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
> >> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> >> ---
> >>
> >> Sander, could you pleas econfirm this works for you?
> 
> Yes this works for me (still on top of the debug patches + pull of the branch igor mentoined),
> but without -global PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off:
> 
> No fw cfg. Bailing out.
> bsel: 0, bus: pci.0
> bsel: 0, bus: pci.0
> bsel: 0, bus: pci.0
> bsel: 0, bus: pci.0
> 

Sander, thanks for testing and reporting the issue in the first place.

Just to be clear: does the patch fix PCI passthrough completely or do
you still need to pass -global
PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off?
Sorry but I couldn't quite understand your reply.




> --
> Sander
> 
> >> Also, Xen really should switch to fw cfg some day ...
> 
> > Yeah, especially because nowadays "-M pc" works with Xen.  It would be 
> > nice if fw_cfg could be enabled even for Xen on all machines except the 
> > legacy "-M xenfv".
> 
> > Stefano, could you give it a shot now that you'll be soon done with 4.4?
> 
> > Paolo
> 
> >>  hw/i386/pc_piix.c | 11 +++++++++++
> >>  1 file changed, 11 insertions(+)
> >>
> >> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> >> index a327d71..1acd2b2 100644
> >> --- a/hw/i386/pc_piix.c
> >> +++ b/hw/i386/pc_piix.c
> >> @@ -793,6 +793,17 @@ static QEMUMachine xenfv_machine = {
> >>      .max_cpus = HVM_MAX_VCPUS,
> >>      .default_machine_opts = "accel=xen",
> >>      .hot_add_cpu = pc_hot_add_cpu,
> >> +    .compat_props = (GlobalProperty[]) {
> >> +        /* xenfv has no fwcfg and so does not load acpi from QEMU.
> >> +         * as such new acpi features don't work.
> >> +         */
> >> +        {
> >> +            .driver   = "PIIX4_PM",
> >> +            .property = "acpi-pci-hotplug-with-bridge-support",
> >> +            .value    = "off",
> >> +        },
> >> +        { /* end of list */ }
> >> +    },
> >>  };
> >>  #endif
> >>
> >>
> 
> 
> 
> 

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Sander Eikelenboom]

Wednesday, February 5, 2014, 5:35:32 PM, you wrote:

> On Tue, 4 Feb 2014, Sander Eikelenboom wrote:
>> Tuesday, February 4, 2014, 10:55:18 PM, you wrote:
>> 
>> > Il 04/02/2014 22:32, Michael S. Tsirkin ha scritto:
>> >> xenfv has no fwcfg and so does not load acpi from QEMU.
>> >> as such new acpi features don't work.
>> >>
>> >> Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
>> >> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>> >> ---
>> >>
>> >> Sander, could you pleas econfirm this works for you?
>> 
>> Yes this works for me (still on top of the debug patches + pull of the branch igor mentoined),
>> but without -global PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off:
>> 
>> No fw cfg. Bailing out.
>> bsel: 0, bus: pci.0
>> bsel: 0, bus: pci.0
>> bsel: 0, bus: pci.0
>> bsel: 0, bus: pci.0
>> 

> Sander, thanks for testing and reporting the issue in the first place.

> Just to be clear: does the patch fix PCI passthrough completely or do
> you still need to pass -global
> PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off?
> Sorry but I couldn't quite understand your reply.

It's fixed with the patch, you don't need to pass that global parameter.
(i only tested it with igor's upcoming branch and the debug-patches (printk's only) applied though)

>> --
>> Sander
>> 
>> >> Also, Xen really should switch to fw cfg some day ...
>> 
>> > Yeah, especially because nowadays "-M pc" works with Xen.  It would be 
>> > nice if fw_cfg could be enabled even for Xen on all machines except the 
>> > legacy "-M xenfv".
>> 
>> > Stefano, could you give it a shot now that you'll be soon done with 4.4?
>> 
>> > Paolo
>> 
>> >>  hw/i386/pc_piix.c | 11 +++++++++++
>> >>  1 file changed, 11 insertions(+)
>> >>
>> >> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>> >> index a327d71..1acd2b2 100644
>> >> --- a/hw/i386/pc_piix.c
>> >> +++ b/hw/i386/pc_piix.c
>> >> @@ -793,6 +793,17 @@ static QEMUMachine xenfv_machine = {
>> >>      .max_cpus = HVM_MAX_VCPUS,
>> >>      .default_machine_opts = "accel=xen",
>> >>      .hot_add_cpu = pc_hot_add_cpu,
>> >> +    .compat_props = (GlobalProperty[]) {
>> >> +        /* xenfv has no fwcfg and so does not load acpi from QEMU.
>> >> +         * as such new acpi features don't work.
>> >> +         */
>> >> +        {
>> >> +            .driver   = "PIIX4_PM",
>> >> +            .property = "acpi-pci-hotplug-with-bridge-support",
>> >> +            .value    = "off",
>> >> +        },
>> >> +        { /* end of list */ }
>> >> +    },
>> >>  };
>> >>  #endif
>> >>
>> >>
>> 
>> 
>> 
>> 

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Stefano Stabellini]

On Wed, 5 Feb 2014, Sander Eikelenboom wrote:
> > On Tue, 4 Feb 2014, Sander Eikelenboom wrote:
> >> Tuesday, February 4, 2014, 10:55:18 PM, you wrote:
> >> 
> >> > Il 04/02/2014 22:32, Michael S. Tsirkin ha scritto:
> >> >> xenfv has no fwcfg and so does not load acpi from QEMU.
> >> >> as such new acpi features don't work.
> >> >>
> >> >> Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
> >> >> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> >> >> ---
> >> >>
> >> >> Sander, could you pleas econfirm this works for you?
> >> 
> >> Yes this works for me (still on top of the debug patches + pull of the branch igor mentoined),
> >> but without -global PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off:
> >> 
> >> No fw cfg. Bailing out.
> >> bsel: 0, bus: pci.0
> >> bsel: 0, bus: pci.0
> >> bsel: 0, bus: pci.0
> >> bsel: 0, bus: pci.0
> >> 
> 
> > Sander, thanks for testing and reporting the issue in the first place.
> 
> > Just to be clear: does the patch fix PCI passthrough completely or do
> > you still need to pass -global
> > PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off?
> > Sorry but I couldn't quite understand your reply.
> 
> It's fixed with the patch, you don't need to pass that global parameter.
> (i only tested it with igor's upcoming branch and the debug-patches (printk's only) applied though)

OK, that's fine, thanks.


> >> --
> >> Sander
> >> 
> >> >> Also, Xen really should switch to fw cfg some day ...
> >> 
> >> > Yeah, especially because nowadays "-M pc" works with Xen.  It would be 
> >> > nice if fw_cfg could be enabled even for Xen on all machines except the 
> >> > legacy "-M xenfv".
> >> 
> >> > Stefano, could you give it a shot now that you'll be soon done with 4.4?
> >> 
> >> > Paolo
> >> 
> >> >>  hw/i386/pc_piix.c | 11 +++++++++++
> >> >>  1 file changed, 11 insertions(+)
> >> >>
> >> >> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> >> >> index a327d71..1acd2b2 100644
> >> >> --- a/hw/i386/pc_piix.c
> >> >> +++ b/hw/i386/pc_piix.c
> >> >> @@ -793,6 +793,17 @@ static QEMUMachine xenfv_machine = {
> >> >>      .max_cpus = HVM_MAX_VCPUS,
> >> >>      .default_machine_opts = "accel=xen",
> >> >>      .hot_add_cpu = pc_hot_add_cpu,
> >> >> +    .compat_props = (GlobalProperty[]) {
> >> >> +        /* xenfv has no fwcfg and so does not load acpi from QEMU.
> >> >> +         * as such new acpi features don't work.
> >> >> +         */
> >> >> +        {
> >> >> +            .driver   = "PIIX4_PM",
> >> >> +            .property = "acpi-pci-hotplug-with-bridge-support",
> >> >> +            .value    = "off",
> >> >> +        },
> >> >> +        { /* end of list */ }
> >> >> +    },
> >> >>  };
> >> >>  #endif
> >> >>
> >> >>
> >> 
> >> 
> >> 
> >> 
> 
> 

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Stefano Stabellini]

On Tue, 4 Feb 2014, Paolo Bonzini wrote:
> Il 04/02/2014 22:32, Michael S. Tsirkin ha scritto:
> > xenfv has no fwcfg and so does not load acpi from QEMU.
> > as such new acpi features don't work.
> > 
> > Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> > 
> > Sander, could you pleas econfirm this works for you?
> > Also, Xen really should switch to fw cfg some day ...
> 
> Yeah, especially because nowadays "-M pc" works with Xen.  It would be nice if
> fw_cfg could be enabled even for Xen on all machines except the legacy "-M
> xenfv".
> 
> Stefano, could you give it a shot now that you'll be soon done with 4.4?

It might not be that straightforward as Xen emulates some devices in the
hypervisor and patches have been recently posted to support multiple
device models for a single VM.

 
> >  hw/i386/pc_piix.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> > 
> > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> > index a327d71..1acd2b2 100644
> > --- a/hw/i386/pc_piix.c
> > +++ b/hw/i386/pc_piix.c
> > @@ -793,6 +793,17 @@ static QEMUMachine xenfv_machine = {
> >      .max_cpus = HVM_MAX_VCPUS,
> >      .default_machine_opts = "accel=xen",
> >      .hot_add_cpu = pc_hot_add_cpu,
> > +    .compat_props = (GlobalProperty[]) {
> > +        /* xenfv has no fwcfg and so does not load acpi from QEMU.
> > +         * as such new acpi features don't work.
> > +         */
> > +        {
> > +            .driver   = "PIIX4_PM",
> > +            .property = "acpi-pci-hotplug-with-bridge-support",
> > +            .value    = "off",
> > +        },
> > +        { /* end of list */ }
> > +    },
> >  };
> >  #endif
> > 
> > 
> 

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Paolo Bonzini]

Il 05/02/2014 17:41, Stefano Stabellini ha scritto:
> > Yeah, especially because nowadays "-M pc" works with Xen.  It would be nice if
> > fw_cfg could be enabled even for Xen on all machines except the legacy "-M
> > xenfv".
> >
> > Stefano, could you give it a shot now that you'll be soon done with 4.4?
>
> It might not be that straightforward as Xen emulates some devices in the
> hypervisor and patches have been recently posted to support multiple
> device models for a single VM.

I'm not sure how this is related to fw_cfg?  fw_cfg is just a simple 
key-value store.  If hvmloader doesn't use it, it should be a burden.

Paolo

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Stefano Stabellini]

On Wed, 5 Feb 2014, Paolo Bonzini wrote:
> Il 05/02/2014 17:41, Stefano Stabellini ha scritto:
> > > Yeah, especially because nowadays "-M pc" works with Xen.  It would be
> > nice if
> > > fw_cfg could be enabled even for Xen on all machines except the legacy "-M
> > > xenfv".
> > >
> > > Stefano, could you give it a shot now that you'll be soon done with 4.4?
> > 
> > It might not be that straightforward as Xen emulates some devices in the
> > hypervisor and patches have been recently posted to support multiple
> > device models for a single VM.
> 
> I'm not sure how this is related to fw_cfg?  fw_cfg is just a simple key-value
> store.  If hvmloader doesn't use it, it should be a burden.

I was referring to the fact that QEMU might not have all the info that
need to be written to fw_cfg when running on Xen: some of the info might
be in the hypervisor and some other in another QEMU instance.
Or do you think that fw_cfg could be written by multiple entities
simultaneously?

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Paolo Bonzini]

Il 05/02/2014 17:54, Stefano Stabellini ha scritto:
>> > I'm not sure how this is related to fw_cfg?  fw_cfg is just a simple key-value
>> > store.  If hvmloader doesn't use it, it should be a burden.
> I was referring to the fact that QEMU might not have all the info that
> need to be written to fw_cfg when running on Xen: some of the info might
> be in the hypervisor and some other in another QEMU instance.
> Or do you think that fw_cfg could be written by multiple entities
> simultaneously?

Wouldn't it be possible to fetch the necessary information via 
hypercalls or in xenstore?

It's possible that some particular fw_cfg entries will be skipped for 
Xen, but most of them should apply.  fw_cfg support would also make it 
possible to use -kernel/-initrd in Xen HVM machines, for example.

Paolo

Re: [Qemu-devel] [PATCH] pc_piix: enable legacy hotplug for Xen

[Stefano Stabellini]

On Wed, 5 Feb 2014, Paolo Bonzini wrote:
> Il 05/02/2014 17:54, Stefano Stabellini ha scritto:
> > > > I'm not sure how this is related to fw_cfg?  fw_cfg is just a simple
> > > key-value
> > > > store.  If hvmloader doesn't use it, it should be a burden.
> > I was referring to the fact that QEMU might not have all the info that
> > need to be written to fw_cfg when running on Xen: some of the info might
> > be in the hypervisor and some other in another QEMU instance.
> > Or do you think that fw_cfg could be written by multiple entities
> > simultaneously?
> 
> Wouldn't it be possible to fetch the necessary information via hypercalls or
> in xenstore?

Probably, at least for the single QEMU case.


> It's possible that some particular fw_cfg entries will be skipped for Xen, but
> most of them should apply.  fw_cfg support would also make it possible to use
> -kernel/-initrd in Xen HVM machines, for example.