[PATCH] x86/numa: Add Devicetree support

[PATCH] x86/numa: Add Devicetree support

[Saurabh Sengar]

Hyper-V has usecases where it need to fetch NUMA information from
Devicetree. Currently, it is not possible to extract the NUMA
information from Devicetree for x86 arch.

Add support for Devicetree in the x86_numa_init function, allowing
the retrieval of NUMA node information from the Devicetree.

Additionally, relocate the x86_dtb_init function before initmem_init
to ensure the Devicetree initialization prior to its utilization in
x86_numa_init.

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
---
 arch/x86/Kconfig        | 1 +
 arch/x86/kernel/setup.c | 2 +-
 arch/x86/mm/numa.c      | 3 +++
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c531b16ee0bf..a2ada193b2d8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1567,6 +1567,7 @@ config NUMA
 	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
 	default y if X86_BIGSMP
 	select USE_PERCPU_NUMA_NODE_ID
+	select OF_NUMA if OF
 	help
 	  Enable NUMA (Non-Uniform Memory Access) support.
 
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index fd975a4a5200..940c92a6a5e9 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1220,6 +1220,7 @@ void __init setup_arch(char **cmdline_p)
 
 	early_acpi_boot_init();
 
+	x86_dtb_init();
 	initmem_init();
 	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
 
@@ -1261,7 +1262,6 @@ void __init setup_arch(char **cmdline_p)
 	 * Read APIC and some other early information from ACPI tables.
 	 */
 	acpi_boot_init();
-	x86_dtb_init();
 
 	/*
 	 * get boot-time SMP configuration:
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 2aadb2019b4f..a6d3d331fda2 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -11,6 +11,7 @@
 #include <linux/nodemask.h>
 #include <linux/sched.h>
 #include <linux/topology.h>
+#include <linux/of.h>
 
 #include <asm/e820/api.h>
 #include <asm/proto.h>
@@ -733,6 +734,8 @@ void __init x86_numa_init(void)
 		if (!numa_init(amd_numa_init))
 			return;
 #endif
+		if (acpi_disabled && !numa_init(of_numa_init))
+			return;
 	}
 
 	numa_init(dummy_numa_init);
-- 
2.34.1

RE: [PATCH] x86/numa: Add Devicetree support

[Saurabh Singh Sengar]

> -----Original Message-----
> From: Saurabh Sengar <ssengar@linux.microsoft.com>
> Sent: Tuesday, June 27, 2023 12:58 PM
> To: tglx@linutronix.de; mingo@redhat.com; bp@alien8.de;
> dave.hansen@linux.intel.com; x86@kernel.org; hpa@zytor.com;
> luto@kernel.org; peterz@infradead.org; Michael Kelley (LINUX)
> <mikelley@microsoft.com>; linux-kernel@vger.kernel.org
> Cc: ssengar@linux.microsoft.com
> Subject: [PATCH] x86/numa: Add Devicetree support
> 
> Hyper-V has usecases where it need to fetch NUMA information from
> Devicetree. Currently, it is not possible to extract the NUMA
> information from Devicetree for x86 arch.
> 
> Add support for Devicetree in the x86_numa_init function, allowing
> the retrieval of NUMA node information from the Devicetree.
> 
> Additionally, relocate the x86_dtb_init function before initmem_init
> to ensure the Devicetree initialization prior to its utilization in
> x86_numa_init.
> 
> Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> ---
>  arch/x86/Kconfig        | 1 +
>  arch/x86/kernel/setup.c | 2 +-
>  arch/x86/mm/numa.c      | 3 +++
>  3 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index c531b16ee0bf..a2ada193b2d8 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1567,6 +1567,7 @@ config NUMA
>  	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
>  	default y if X86_BIGSMP
>  	select USE_PERCPU_NUMA_NODE_ID
> +	select OF_NUMA if OF
>  	help
>  	  Enable NUMA (Non-Uniform Memory Access) support.
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index fd975a4a5200..940c92a6a5e9 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -1220,6 +1220,7 @@ void __init setup_arch(char **cmdline_p)
> 
>  	early_acpi_boot_init();
> 
> +	x86_dtb_init();
>  	initmem_init();
>  	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
> 
> @@ -1261,7 +1262,6 @@ void __init setup_arch(char **cmdline_p)
>  	 * Read APIC and some other early information from ACPI tables.
>  	 */
>  	acpi_boot_init();
> -	x86_dtb_init();
> 
>  	/*
>  	 * get boot-time SMP configuration:
> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> index 2aadb2019b4f..a6d3d331fda2 100644
> --- a/arch/x86/mm/numa.c
> +++ b/arch/x86/mm/numa.c
> @@ -11,6 +11,7 @@
>  #include <linux/nodemask.h>
>  #include <linux/sched.h>
>  #include <linux/topology.h>
> +#include <linux/of.h>
> 
>  #include <asm/e820/api.h>
>  #include <asm/proto.h>
> @@ -733,6 +734,8 @@ void __init x86_numa_init(void)
>  		if (!numa_init(amd_numa_init))
>  			return;
>  #endif
> +		if (acpi_disabled && !numa_init(of_numa_init))
> +			return;
>  	}
> 
>  	numa_init(dummy_numa_init);
> --
> 2.34.1

Hi x86 Maintainers,

May I get your feedback on this patch.

Regards,
Saurabh

RE: [PATCH] x86/numa: Add Devicetree support

[Saurabh Singh Sengar]

> -----Original Message-----
> From: Saurabh Singh Sengar <ssengar@microsoft.com>
> Sent: Wednesday, July 12, 2023 1:42 PM
> To: Saurabh Sengar <ssengar@linux.microsoft.com>; tglx@linutronix.de;
> mingo@redhat.com; bp@alien8.de; dave.hansen@linux.intel.com;
> x86@kernel.org; hpa@zytor.com; luto@kernel.org; peterz@infradead.org;
> Michael Kelley (LINUX) <mikelley@microsoft.com>; linux-
> kernel@vger.kernel.org; Sharath George John <sgeorgejohn@microsoft.com>
> Subject: [EXTERNAL] RE: [PATCH] x86/numa: Add Devicetree support
> 
> 
> 
> > -----Original Message-----
> > From: Saurabh Sengar <ssengar@linux.microsoft.com>
> > Sent: Tuesday, June 27, 2023 12:58 PM
> > To: tglx@linutronix.de; mingo@redhat.com; bp@alien8.de;
> > dave.hansen@linux.intel.com; x86@kernel.org; hpa@zytor.com;
> > luto@kernel.org; peterz@infradead.org; Michael Kelley (LINUX)
> > <mikelley@microsoft.com>; linux-kernel@vger.kernel.org
> > Cc: ssengar@linux.microsoft.com
> > Subject: [PATCH] x86/numa: Add Devicetree support
> >
> > Hyper-V has usecases where it need to fetch NUMA information from
> > Devicetree. Currently, it is not possible to extract the NUMA
> > information from Devicetree for x86 arch.
> >
> > Add support for Devicetree in the x86_numa_init function, allowing the
> > retrieval of NUMA node information from the Devicetree.
> >
> > Additionally, relocate the x86_dtb_init function before initmem_init
> > to ensure the Devicetree initialization prior to its utilization in
> > x86_numa_init.
> >
> > Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> > ---
> >  arch/x86/Kconfig        | 1 +
> >  arch/x86/kernel/setup.c | 2 +-
> >  arch/x86/mm/numa.c      | 3 +++
> >  3 files changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index
> > c531b16ee0bf..a2ada193b2d8 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -1567,6 +1567,7 @@ config NUMA
> >  	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
> >  	default y if X86_BIGSMP
> >  	select USE_PERCPU_NUMA_NODE_ID
> > +	select OF_NUMA if OF
> >  	help
> >  	  Enable NUMA (Non-Uniform Memory Access) support.
> >
> > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index
> > fd975a4a5200..940c92a6a5e9 100644
> > --- a/arch/x86/kernel/setup.c
> > +++ b/arch/x86/kernel/setup.c
> > @@ -1220,6 +1220,7 @@ void __init setup_arch(char **cmdline_p)
> >
> >  	early_acpi_boot_init();
> >
> > +	x86_dtb_init();
> >  	initmem_init();
> >  	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
> >
> > @@ -1261,7 +1262,6 @@ void __init setup_arch(char **cmdline_p)
> >  	 * Read APIC and some other early information from ACPI tables.
> >  	 */
> >  	acpi_boot_init();
> > -	x86_dtb_init();
> >
> >  	/*
> >  	 * get boot-time SMP configuration:
> > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index
> > 2aadb2019b4f..a6d3d331fda2 100644
> > --- a/arch/x86/mm/numa.c
> > +++ b/arch/x86/mm/numa.c
> > @@ -11,6 +11,7 @@
> >  #include <linux/nodemask.h>
> >  #include <linux/sched.h>
> >  #include <linux/topology.h>
> > +#include <linux/of.h>
> >
> >  #include <asm/e820/api.h>
> >  #include <asm/proto.h>
> > @@ -733,6 +734,8 @@ void __init x86_numa_init(void)
> >  		if (!numa_init(amd_numa_init))
> >  			return;
> >  #endif
> > +		if (acpi_disabled && !numa_init(of_numa_init))
> > +			return;
> >  	}
> >
> >  	numa_init(dummy_numa_init);
> > --
> > 2.34.1
> 
> Hi x86 Maintainers,
> 
> May I get your feedback on this patch.
> 
> Regards,
> Saurabh

Kind reminder to review this patch.

- Saurabh

RE: [PATCH] x86/numa: Add Devicetree support

[Michael Kelley (LINUX)]

From: Saurabh Sengar <ssengar@linux.microsoft.com> Sent: Tuesday, June 27, 2023 12:28 AM
> 
> Hyper-V has usecases where it need to fetch NUMA information from
> Devicetree. Currently, it is not possible to extract the NUMA
> information from Devicetree for x86 arch.
> 
> Add support for Devicetree in the x86_numa_init function, allowing
> the retrieval of NUMA node information from the Devicetree.
> 
> Additionally, relocate the x86_dtb_init function before initmem_init
> to ensure the Devicetree initialization prior to its utilization in
> x86_numa_init.
> 
> Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> ---
>  arch/x86/Kconfig        | 1 +
>  arch/x86/kernel/setup.c | 2 +-
>  arch/x86/mm/numa.c      | 3 +++
>  3 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index c531b16ee0bf..a2ada193b2d8 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1567,6 +1567,7 @@ config NUMA
>  	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
>  	default y if X86_BIGSMP
>  	select USE_PERCPU_NUMA_NODE_ID
> +	select OF_NUMA if OF
>  	help
>  	  Enable NUMA (Non-Uniform Memory Access) support.
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index fd975a4a5200..940c92a6a5e9 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -1220,6 +1220,7 @@ void __init setup_arch(char **cmdline_p)
> 
>  	early_acpi_boot_init();
> 
> +	x86_dtb_init();
>  	initmem_init();
>  	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
> 
> @@ -1261,7 +1262,6 @@ void __init setup_arch(char **cmdline_p)
>  	 * Read APIC and some other early information from ACPI tables.
>  	 */
>  	acpi_boot_init();
> -	x86_dtb_init();
> 
>  	/*
>  	 * get boot-time SMP configuration:
> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> index 2aadb2019b4f..a6d3d331fda2 100644
> --- a/arch/x86/mm/numa.c
> +++ b/arch/x86/mm/numa.c
> @@ -11,6 +11,7 @@
>  #include <linux/nodemask.h>
>  #include <linux/sched.h>
>  #include <linux/topology.h>
> +#include <linux/of.h>
> 
>  #include <asm/e820/api.h>
>  #include <asm/proto.h>
> @@ -733,6 +734,8 @@ void __init x86_numa_init(void)
>  		if (!numa_init(amd_numa_init))
>  			return;
>  #endif
> +		if (acpi_disabled && !numa_init(of_numa_init))
> +			return;
>  	}
> 
>  	numa_init(dummy_numa_init);
> --
> 2.34.1

This looks good to me.  I've looked and don't see any
obvious issues in moving x86_dtb_init() earlier in
setup_arch().  But I also know the setup ordering can
be very tricky to get working correctly with a wide
range of platforms, and I don't have that expertise.
But with those caveats,

Reviewed-by: Michael Kelley <mikelley@microsoft.com>

RE: [PATCH] x86/numa: Add Devicetree support

[Saurabh Singh Sengar]

> -----Original Message-----
> From: Michael Kelley (LINUX) <mikelley@microsoft.com>
> Sent: Thursday, August 3, 2023 12:19 AM
> To: Saurabh Sengar <ssengar@linux.microsoft.com>; tglx@linutronix.de;
> mingo@redhat.com; bp@alien8.de; dave.hansen@linux.intel.com;
> x86@kernel.org; hpa@zytor.com; luto@kernel.org; peterz@infradead.org;
> linux-kernel@vger.kernel.org
> Subject: [EXTERNAL] RE: [PATCH] x86/numa: Add Devicetree support
> 
> From: Saurabh Sengar <ssengar@linux.microsoft.com> Sent: Tuesday, June
> 27, 2023 12:28 AM
> >
> > Hyper-V has usecases where it need to fetch NUMA information from
> > Devicetree. Currently, it is not possible to extract the NUMA
> > information from Devicetree for x86 arch.
> >
> > Add support for Devicetree in the x86_numa_init function, allowing the
> > retrieval of NUMA node information from the Devicetree.
> >
> > Additionally, relocate the x86_dtb_init function before initmem_init
> > to ensure the Devicetree initialization prior to its utilization in
> > x86_numa_init.
> >
> > Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> > ---
> >  arch/x86/Kconfig        | 1 +
> >  arch/x86/kernel/setup.c | 2 +-
> >  arch/x86/mm/numa.c      | 3 +++
> >  3 files changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index
> > c531b16ee0bf..a2ada193b2d8 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -1567,6 +1567,7 @@ config NUMA
> >  	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
> >  	default y if X86_BIGSMP
> >  	select USE_PERCPU_NUMA_NODE_ID
> > +	select OF_NUMA if OF
> >  	help
> >  	  Enable NUMA (Non-Uniform Memory Access) support.
> >
> > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index
> > fd975a4a5200..940c92a6a5e9 100644
> > --- a/arch/x86/kernel/setup.c
> > +++ b/arch/x86/kernel/setup.c
> > @@ -1220,6 +1220,7 @@ void __init setup_arch(char **cmdline_p)
> >
> >  	early_acpi_boot_init();
> >
> > +	x86_dtb_init();
> >  	initmem_init();
> >  	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
> >
> > @@ -1261,7 +1262,6 @@ void __init setup_arch(char **cmdline_p)
> >  	 * Read APIC and some other early information from ACPI tables.
> >  	 */
> >  	acpi_boot_init();
> > -	x86_dtb_init();
> >
> >  	/*
> >  	 * get boot-time SMP configuration:
> > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index
> > 2aadb2019b4f..a6d3d331fda2 100644
> > --- a/arch/x86/mm/numa.c
> > +++ b/arch/x86/mm/numa.c
> > @@ -11,6 +11,7 @@
> >  #include <linux/nodemask.h>
> >  #include <linux/sched.h>
> >  #include <linux/topology.h>
> > +#include <linux/of.h>
> >
> >  #include <asm/e820/api.h>
> >  #include <asm/proto.h>
> > @@ -733,6 +734,8 @@ void __init x86_numa_init(void)
> >  		if (!numa_init(amd_numa_init))
> >  			return;
> >  #endif
> > +		if (acpi_disabled && !numa_init(of_numa_init))
> > +			return;
> >  	}
> >
> >  	numa_init(dummy_numa_init);
> > --
> > 2.34.1
> 
> This looks good to me.  I've looked and don't see any obvious issues in
> moving x86_dtb_init() earlier in setup_arch().  But I also know the setup
> ordering can be very tricky to get working correctly with a wide range of
> platforms, and I don't have that expertise.
> But with those caveats,
> 
> Reviewed-by: Michael Kelley <mikelley@microsoft.com>

Hi X86 Maintainers,

Is this good to be accepted ?

- Saurabh

Re: [PATCH] x86/numa: Add Devicetree support

[Saurabh Singh Sengar]

On Fri, Aug 11, 2023 at 10:29:57AM +0000, Saurabh Singh Sengar wrote:
> 
> 
> > -----Original Message-----
> > From: Michael Kelley (LINUX) <mikelley@microsoft.com>
> > Sent: Thursday, August 3, 2023 12:19 AM
> > To: Saurabh Sengar <ssengar@linux.microsoft.com>; tglx@linutronix.de;
> > mingo@redhat.com; bp@alien8.de; dave.hansen@linux.intel.com;
> > x86@kernel.org; hpa@zytor.com; luto@kernel.org; peterz@infradead.org;
> > linux-kernel@vger.kernel.org
> > Subject: [EXTERNAL] RE: [PATCH] x86/numa: Add Devicetree support
> > 
> > From: Saurabh Sengar <ssengar@linux.microsoft.com> Sent: Tuesday, June
> > 27, 2023 12:28 AM
> > >
> > > Hyper-V has usecases where it need to fetch NUMA information from
> > > Devicetree. Currently, it is not possible to extract the NUMA
> > > information from Devicetree for x86 arch.
> > >
> > > Add support for Devicetree in the x86_numa_init function, allowing the
> > > retrieval of NUMA node information from the Devicetree.
> > >
> > > Additionally, relocate the x86_dtb_init function before initmem_init
> > > to ensure the Devicetree initialization prior to its utilization in
> > > x86_numa_init.
> > >
> > > Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> > > ---
> > >  arch/x86/Kconfig        | 1 +
> > >  arch/x86/kernel/setup.c | 2 +-
> > >  arch/x86/mm/numa.c      | 3 +++
> > >  3 files changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index
> > > c531b16ee0bf..a2ada193b2d8 100644
> > > --- a/arch/x86/Kconfig
> > > +++ b/arch/x86/Kconfig
> > > @@ -1567,6 +1567,7 @@ config NUMA
> > >  	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
> > >  	default y if X86_BIGSMP
> > >  	select USE_PERCPU_NUMA_NODE_ID
> > > +	select OF_NUMA if OF
> > >  	help
> > >  	  Enable NUMA (Non-Uniform Memory Access) support.
> > >
> > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index
> > > fd975a4a5200..940c92a6a5e9 100644
> > > --- a/arch/x86/kernel/setup.c
> > > +++ b/arch/x86/kernel/setup.c
> > > @@ -1220,6 +1220,7 @@ void __init setup_arch(char **cmdline_p)
> > >
> > >  	early_acpi_boot_init();
> > >
> > > +	x86_dtb_init();
> > >  	initmem_init();
> > >  	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
> > >
> > > @@ -1261,7 +1262,6 @@ void __init setup_arch(char **cmdline_p)
> > >  	 * Read APIC and some other early information from ACPI tables.
> > >  	 */
> > >  	acpi_boot_init();
> > > -	x86_dtb_init();
> > >
> > >  	/*
> > >  	 * get boot-time SMP configuration:
> > > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index
> > > 2aadb2019b4f..a6d3d331fda2 100644
> > > --- a/arch/x86/mm/numa.c
> > > +++ b/arch/x86/mm/numa.c
> > > @@ -11,6 +11,7 @@
> > >  #include <linux/nodemask.h>
> > >  #include <linux/sched.h>
> > >  #include <linux/topology.h>
> > > +#include <linux/of.h>
> > >
> > >  #include <asm/e820/api.h>
> > >  #include <asm/proto.h>
> > > @@ -733,6 +734,8 @@ void __init x86_numa_init(void)
> > >  		if (!numa_init(amd_numa_init))
> > >  			return;
> > >  #endif
> > > +		if (acpi_disabled && !numa_init(of_numa_init))
> > > +			return;
> > >  	}
> > >
> > >  	numa_init(dummy_numa_init);
> > > --
> > > 2.34.1
> > 
> > This looks good to me.  I've looked and don't see any obvious issues in
> > moving x86_dtb_init() earlier in setup_arch().  But I also know the setup
> > ordering can be very tricky to get working correctly with a wide range of
> > platforms, and I don't have that expertise.
> > But with those caveats,
> > 
> > Reviewed-by: Michael Kelley <mikelley@microsoft.com>
> 
> Hi X86 Maintainers,
> 
> Is this good to be accepted ?

Thomas/Borislav,

Kind reminder to review this.

- Saurabh


> 
> - Saurabh

Re: [PATCH] x86/numa: Add Devicetree support

[Thomas Gleixner]

On Tue, Jun 27 2023 at 00:28, Saurabh Sengar wrote:
> Hyper-V has usecases where it need to fetch NUMA information from
> Devicetree. Currently, it is not possible to extract the NUMA
> information from Devicetree for x86 arch.
>
> Add support for Devicetree in the x86_numa_init function, allowing
> the retrieval of NUMA node information from the Devicetree.
>
> Additionally, relocate the x86_dtb_init function before initmem_init
> to ensure the Devicetree initialization prior to its utilization in
> x86_numa_init.

Moving dtb_init() is not really a good idea. The APIC/IO-APIC
enumeration is post initmem_init() on purpose and the ongoing rework of
the topology evaluation relies on that.

What you really want is to split dtb_init() into two parts:

   1) x86_flattree_get_config() which can be invoked before initmem init
      like ACPI has an early init part so SRAT parsing can be done in
      the numa initialization.

   2) The APIC/IOAPIC registration part, which stays where it is.

This split wants to be a seperate change.

Thanks,

        tglx



   

Re: [PATCH] x86/numa: Add Devicetree support

[Saurabh Singh Sengar]

On Thu, Aug 24, 2023 at 05:28:37PM +0200, Thomas Gleixner wrote:
> On Tue, Jun 27 2023 at 00:28, Saurabh Sengar wrote:
> > Hyper-V has usecases where it need to fetch NUMA information from
> > Devicetree. Currently, it is not possible to extract the NUMA
> > information from Devicetree for x86 arch.
> >
> > Add support for Devicetree in the x86_numa_init function, allowing
> > the retrieval of NUMA node information from the Devicetree.
> >
> > Additionally, relocate the x86_dtb_init function before initmem_init
> > to ensure the Devicetree initialization prior to its utilization in
> > x86_numa_init.
> 
> Moving dtb_init() is not really a good idea. The APIC/IO-APIC
> enumeration is post initmem_init() on purpose and the ongoing rework of
> the topology evaluation relies on that.
> 
> What you really want is to split dtb_init() into two parts:
> 
>    1) x86_flattree_get_config() which can be invoked before initmem init
>       like ACPI has an early init part so SRAT parsing can be done in
>       the numa initialization.
> 
>    2) The APIC/IOAPIC registration part, which stays where it is.
> 
> This split wants to be a seperate change.

Thanks for the review, I will send the v2 with suggested modifications.

- Saurabh

> 
> Thanks,
> 
>         tglx
> 
> 
> 
>