> -----Original Message-----
> From: Auger Eric [mailto:eric.au...@redhat.com]
> Sent: 29 March 2019 09:32
> To: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com>;
> qemu-devel@nongnu.org; qemu-...@nongnu.org; imamm...@redhat.com;
> peter.mayd...@linaro.org; shannon.zha...@gmail.com;
> sa...@linux.intel.com; sebastien.bo...@intel.com
> Cc: Linuxarm <linux...@huawei.com>; xuwei (O) <xuw...@huawei.com>;
> Laszlo Ersek <ler...@redhat.com>; Ard Biesheuvel
> <ard.biesheu...@linaro.org>; Leif Lindholm <leif.lindh...@arm.com>
> Subject: Re: [PATCH v3 07/10] hw/arm/virt: Introduce opt-in feature "fdt"
>
> Hi Shameer,
>
> [ + Laszlo, Ard, Leif ]
>
> On 3/21/19 11:47 AM, Shameer Kolothum wrote:
> > This is to disable/enable populating DT nodes in case
> > any conflict with acpi tables. The default is "off".
> The name of the option sounds misleading to me. Also we don't really
> know the scope of the disablement. At the moment this just aims to
> prevent the hotpluggable dt nodes from being added if we boot in ACPI mode.
>
> >
> > This will be used in subsequent patch where cold plug
> > device-memory support is added for DT boot.
> I am concerned about the fact that in dt mode, by default, you won't see
> any PCDIMM nodes.
> >
> > If DT memory node support is added for cold-plugged device
> > memory, those memory will be visible to Guest kernel via
> > UEFI GetMemoryMap() and gets treated as early boot memory.
> Don't we have an issue in UEFI then. Normally the SRAT indicates whether
> the slots are hotpluggable or not. Shouldn't the UEFI code look at this
> info.
Sorry I missed this part. Yes, that will be a more cleaner solution.
Also, to be more clear on what happens,
Guest ACPI boot with "fdt=on" ,
From kernel log,
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000040000000-0x00000000bbf5ffff]
[ 0.000000] node 0: [mem 0x00000000bbf60000-0x00000000bbffffff]
[ 0.000000] node 0: [mem 0x00000000bc000000-0x00000000bc02ffff]
[ 0.000000] node 0: [mem 0x00000000bc030000-0x00000000bc36ffff]
[ 0.000000] node 0: [mem 0x00000000bc370000-0x00000000bf64ffff]
[ 0.000000] node 0: [mem 0x00000000bf650000-0x00000000bf6dffff]
[ 0.000000] node 0: [mem 0x00000000bf6e0000-0x00000000bf6effff]
[ 0.000000] node 0: [mem 0x00000000bf6f0000-0x00000000bf80ffff]
[ 0.000000] node 0: [mem 0x00000000bf810000-0x00000000bfffffff]
[ 0.000000] node 0: [mem 0x00000000c0000000-0x00000000ffffffff] -->
This is the hotpluggable memory node from DT.
[ 0.000000] Zeroed struct page in unavailable ranges: 1040 pages
[ 0.000000] Initmem setup node 0 [mem 0x0000000040000000-0x00000000ffffffff]
Guest ACPI boot with "fdt=off" ,
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000040000000-0x00000000bbf5ffff]
[ 0.000000] node 0: [mem 0x00000000bbf60000-0x00000000bbffffff]
[ 0.000000] node 0: [mem 0x00000000bc000000-0x00000000bc02ffff]
[ 0.000000] node 0: [mem 0x00000000bc030000-0x00000000bc36ffff]
[ 0.000000] node 0: [mem 0x00000000bc370000-0x00000000bf64ffff]
[ 0.000000] node 0: [mem 0x00000000bf650000-0x00000000bf6dffff]
[ 0.000000] node 0: [mem 0x00000000bf6e0000-0x00000000bf6effff]
[ 0.000000] node 0: [mem 0x00000000bf6f0000-0x00000000bf80ffff]
[ 0.000000] node 0: [mem 0x00000000bf810000-0x00000000bfffffff]
[ 0.000000] Zeroed struct page in unavailable ranges: 1040 pages
[ 0.000000] Initmem setup node 0 [mem 0x0000000040000000-0x00000000bfffffff
The hotpluggable memory node is absent from early memory nodes here.
As you said, it could be possible to detect this node using SRAT in UEFI.
Cheers,
Shameer
> > Hence memory becomes non hot-un-unpluggable even if Guest
> > is booted in ACPI mode.
>
>
>
> >
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com>
> > ---
> > hw/arm/virt.c | 23 +++++++++++++++++++++++
> > include/hw/arm/virt.h | 1 +
> > 2 files changed, 24 insertions(+)
> >
> > diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> > index 13db0e9..b602151 100644
> > --- a/hw/arm/virt.c
> > +++ b/hw/arm/virt.c
> > @@ -1717,6 +1717,20 @@ static void virt_set_highmem(Object *obj, bool
> value, Error **errp)
> > vms->highmem = value;
> > }
> >
> > +static bool virt_get_fdt(Object *obj, Error **errp)
> > +{
> > + VirtMachineState *vms = VIRT_MACHINE(obj);
> > +
> > + return vms->use_fdt;
> > +}
> > +
> > +static void virt_set_fdt(Object *obj, bool value, Error **errp)
> > +{
> > + VirtMachineState *vms = VIRT_MACHINE(obj);
> > +
> > + vms->use_fdt = value;
> > +}
> > +
> > static bool virt_get_its(Object *obj, Error **errp)
> > {
> > VirtMachineState *vms = VIRT_MACHINE(obj);
> > @@ -2005,6 +2019,15 @@ static void virt_instance_init(Object *obj)
> > object_property_set_description(obj, "gic-version",
> > "Set GIC version. "
> > "Valid values are 2, 3 and host",
> NULL);
> > + /* fdt is disabled by default */
> > + vms->use_fdt = false;
> > + object_property_add_bool(obj, "fdt", virt_get_fdt,
> > + virt_set_fdt, NULL);
> > + object_property_set_description(obj, "fdt",
> > + "Set on/off to enable/disable
> device tree "
> > + "nodes in case any conflict with
> ACPI"
> in case of
>
> Thanks
>
> Eric
> > + "(eg: device memory node)",
> > + NULL);
> >
> > vms->highmem_ecam = !vmc->no_highmem_ecam;
> >
> > diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
> > index c5e4c96..14b2e0a 100644
> > --- a/include/hw/arm/virt.h
> > +++ b/include/hw/arm/virt.h
> > @@ -119,6 +119,7 @@ typedef struct {
> > bool highmem_ecam;
> > bool its;
> > bool virt;
> > + bool use_fdt;
> > int32_t gic_version;
> > VirtIOMMUType iommu;
> > struct arm_boot_info bootinfo;
> >
