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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 04/13] iommu/vt-d: Add helper and flag to
 check/disable posted MSI
In-Reply-To: <20231112041643.2868316-5-jacob.jun.pan@linux.intel.com>
References: <20231112041643.2868316-1-jacob.jun.pan@linux.intel.com>
 <20231112041643.2868316-5-jacob.jun.pan@linux.intel.com>
Date:   Wed, 06 Dec 2023 17:49:04 +0100
Message-ID: <87o7f3uvi7.ffs@tglx>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

On Sat, Nov 11 2023 at 20:16, Jacob Pan wrote:
> Allow command line opt-out posted MSI under CONFIG_X86_POSTED_MSI=y.
> And add a helper function for testing if posted MSI is supported on the
> CPU side.

That's backwards. You want command line opt-in first and not enforce
this posted muck on everyone including RT which will regress and suffer
from that.