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From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: LKML <linux-kernel@vger.kernel.org>,
	X86 Kernel <x86@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
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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>,
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	"Robin Murphy" <robin.murphy@arm.com>,
	Jacob Pan <jacob.jun.pan@linux.intel.com>
Subject: [PATCH 05/15] x86/irq: Reserve a per CPU IDT vector for posted MSIs
Date: Fri, 26 Jan 2024 15:42:27 -0800
Message-Id: <20240126234237.547278-6-jacob.jun.pan@linux.intel.com>
In-Reply-To: <20240126234237.547278-1-jacob.jun.pan@linux.intel.com>
References: <20240126234237.547278-1-jacob.jun.pan@linux.intel.com>
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When posted MSI is enabled, all device MSIs are multiplexed into a single
notification vector. MSI handlers will be de-multiplexed at run-time by
system software without IDT delivery.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
 arch/x86/include/asm/irq_vectors.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index 3a19904c2db6..08329bef5b1d 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -99,9 +99,16 @@
 
 #define LOCAL_TIMER_VECTOR		0xec
 
+/*
+ * Posted interrupt notification vector for all device MSIs delivered to
+ * the host kernel.
+ */
+#define POSTED_MSI_NOTIFICATION_VECTOR	0xeb
 #define NR_VECTORS			 256
 
-#ifdef CONFIG_X86_LOCAL_APIC
+#ifdef X86_POSTED_MSI
+#define FIRST_SYSTEM_VECTOR		POSTED_MSI_NOTIFICATION_VECTOR
+#elif defined(CONFIG_X86_LOCAL_APIC)
 #define FIRST_SYSTEM_VECTOR		LOCAL_TIMER_VECTOR
 #else
 #define FIRST_SYSTEM_VECTOR		NR_VECTORS
-- 
2.25.1