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Message-ID: <89927174-6ca9-4299-8157-a0404b30b156@gmail.com>
Date: Fri, 5 Apr 2024 10:28:59 +0800
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Subject: Re: [PATCH 04/15] x86/irq: Add a Kconfig option for posted MSI
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To: Jacob Pan <jacob.jun.pan@linux.intel.com>,
 LKML <linux-kernel@vger.kernel.org>, X86 Kernel <x86@kernel.org>,
 Peter Zijlstra <peterz@infradead.org>, iommu@lists.linux.dev,
 Thomas Gleixner <tglx@linutronix.de>, Lu Baolu <baolu.lu@linux.intel.com>,
 kvm@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
 Joerg Roedel <joro@8bytes.org>, "H. Peter Anvin" <hpa@zytor.com>,
 Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>
Cc: Paul Luse <paul.e.luse@intel.com>, Dan Williams
 <dan.j.williams@intel.com>, Jens Axboe <axboe@kernel.dk>,
 Raj Ashok <ashok.raj@intel.com>, "Tian, Kevin" <kevin.tian@intel.com>,
 maz@kernel.org, seanjc@google.com, Robin Murphy <robin.murphy@arm.com>
References: <20240126234237.547278-1-jacob.jun.pan@linux.intel.com>
 <20240126234237.547278-5-jacob.jun.pan@linux.intel.com>
From: Robert Hoo <robert.hoo.linux@gmail.com>
In-Reply-To: <20240126234237.547278-5-jacob.jun.pan@linux.intel.com>
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On 1/27/2024 7:42 AM, Jacob Pan wrote:
> This option will be used to support delivering MSIs as posted
> interrupts. Interrupt remapping is required.
> 
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> ---
>   arch/x86/Kconfig | 11 +++++++++++
>   1 file changed, 11 insertions(+)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 5edec175b9bf..79f04ee2b91c 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -463,6 +463,17 @@ config X86_X2APIC
>   
>   	  If you don't know what to do here, say N.
>   
> +config X86_POSTED_MSI
> +	bool "Enable MSI and MSI-x delivery by posted interrupts"
> +	depends on X86_X2APIC && X86_64 && IRQ_REMAP

Does posted_msi really depend on x2APIC? PID.NDST encoding supports both xAPIC 
and x2APIC.
If posted_msi posts more stringent requirement, I think it deserves an 
explanation in this patch's description.

And, X86_X2APIC already depends on IRQ_REMAP, can we just list one of them here?