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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>,
        LKML <linux-kernel@vger.kernel.org>, X86 Kernel <x86@kernel.org>,
        iommu@lists.linux.dev, 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:     Raj Ashok <ashok.raj@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>, maz@kernel.org,
        peterz@infradead.org, seanjc@google.com,
        Robin Murphy <robin.murphy@arm.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>
Subject: Re: [PATCH RFC 12/13] iommu/vt-d: Add a helper to retrieve PID address
In-Reply-To: <20231112041643.2868316-13-jacob.jun.pan@linux.intel.com>
References: <20231112041643.2868316-1-jacob.jun.pan@linux.intel.com>
 <20231112041643.2868316-13-jacob.jun.pan@linux.intel.com>
Date:   Wed, 06 Dec 2023 21:19:11 +0100
Message-ID: <874jgvuls0.ffs@tglx>
MIME-Version: 1.0
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On Sat, Nov 11 2023 at 20:16, Jacob Pan wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
>
> When programming IRTE for posted mode, we need to retrieve the
> physical

we need .... I surely did not write this changelog.

> address of the posted interrupt descriptor (PID) that belongs to it's
> target CPU.
>
> This per CPU PID has already been set up during cpu_init().

This information is useful because?

> +static u64 get_pi_desc_addr(struct irq_data *irqd)
> +{
> +	int cpu = cpumask_first(irq_data_get_effective_affinity_mask(irqd));

The effective affinity mask is magically correct when this is called?