linux-kernel - [PATCH v2 03/13] x86/irq: Remove bitfields in posted interrupt descriptor

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Date: Fri,  5 Apr 2024 15:31:00 -0700
From: Jacob Pan <jacob.jun.pan@...ux.intel.com>
To: LKML <linux-kernel@...r.kernel.org>,
	X86 Kernel <x86@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	iommu@...ts.linux.dev,
	Thomas Gleixner <tglx@...utronix.de>,
	"Lu Baolu" <baolu.lu@...ux.intel.com>,
	kvm@...r.kernel.org,
	Dave Hansen <dave.hansen@...el.com>,
	Joerg Roedel <joro@...tes.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Borislav Petkov" <bp@...en8.de>,
	"Ingo Molnar" <mingo@...hat.com>
Cc: Paul Luse <paul.e.luse@...el.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Jens Axboe <axboe@...nel.dk>,
	Raj Ashok <ashok.raj@...el.com>,
	"Tian, Kevin" <kevin.tian@...el.com>,
	maz@...nel.org,
	seanjc@...gle.com,
	"Robin Murphy" <robin.murphy@....com>,
	jim.harris@...sung.com,
	a.manzanares@...sung.com,
	"Bjorn Helgaas" <helgaas@...nel.org>,
	guang.zeng@...el.com,
	robert.hoo.linux@...il.com,
	Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: [PATCH v2 03/13] x86/irq: Remove bitfields in posted interrupt descriptor

Mixture of bitfields and types is weird and really not intuitive, remove
bitfields and use typed data exclusively.

Link: https://lore.kernel.org/all/20240404101735.402feec8@jacob-builder/T/#mf66e34a82a48f4d8e2926b5581eff59a122de53a
Suggested-by: Sean Christopherson <seanjc@...gle.com>
Suggested-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>

---
v2:
	- Replace bitfields, no more mix.
---
 arch/x86/include/asm/posted_intr.h | 10 +---------
 arch/x86/kvm/vmx/posted_intr.c     |  4 ++--
 arch/x86/kvm/vmx/vmx.c             |  2 +-
 3 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/posted_intr.h b/arch/x86/include/asm/posted_intr.h
index acf237b2882e..c682c41d4e44 100644
--- a/arch/x86/include/asm/posted_intr.h
+++ b/arch/x86/include/asm/posted_intr.h
@@ -15,17 +15,9 @@ struct pi_desc {
 	};
 	union {
 		struct {
-				/* bit 256 - Outstanding Notification */
-			u16	on	: 1,
-				/* bit 257 - Suppress Notification */
-				sn	: 1,
-				/* bit 271:258 - Reserved */
-				rsvd_1	: 14;
-				/* bit 279:272 - Notification Vector */
+			u16	notif_ctrl; /* Suppress and outstanding bits */
 			u8	nv;
-				/* bit 287:280 - Reserved */
 			u8	rsvd_2;
-				/* bit 319:288 - Notification Destination */
 			u32	ndst;
 		};
 		u64 control;
diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c
index af662312fd07..592dbb765675 100644
--- a/arch/x86/kvm/vmx/posted_intr.c
+++ b/arch/x86/kvm/vmx/posted_intr.c
@@ -107,7 +107,7 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu)
 		 * handle task migration (@cpu != vcpu->cpu).
 		 */
 		new.ndst = dest;
-		new.sn = 0;
+		new.notif_ctrl &= ~POSTED_INTR_SN;
 
 		/*
 		 * Restore the notification vector; in the blocking case, the
@@ -157,7 +157,7 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu)
 		      &per_cpu(wakeup_vcpus_on_cpu, vcpu->cpu));
 	raw_spin_unlock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu));
 
-	WARN(pi_desc->sn, "PI descriptor SN field set before blocking");
+	WARN(pi_desc->notif_ctrl & POSTED_INTR_SN, "PI descriptor SN field set before blocking");
 
 	old.control = READ_ONCE(pi_desc->control);
 	do {
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d94bb069bac9..50580bbfba5d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4843,7 +4843,7 @@ static void __vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 	 * or POSTED_INTR_WAKEUP_VECTOR.
 	 */
 	vmx->pi_desc.nv = POSTED_INTR_VECTOR;
-	vmx->pi_desc.sn = 1;
+	vmx->pi_desc.notif_ctrl |= POSTED_INTR_SN;
 }
 
 static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
-- 
2.25.1