Commit 2254808b authored by Jacob Pan's avatar Jacob Pan Committed by Thomas Gleixner
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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. Bitfields often result in
inferior machine code.

Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarJacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240423174114.526704-4-jacob.jun.pan@linux.intel.com
Link: https://lore.kernel.org/all/20240404101735.402feec8@jacob-builder/T/#mf66e34a82a48f4d8e2926b5581eff59a122de53a
parent 4ec8fd03

arch/x86/include/asm/posted_intr.h

+12 −9
Original line number Diff line number Diff line
@@ -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	notifications; /* Suppress and outstanding bits */

			u8	nv;

				/* bit 287:280 - Reserved */

			u8	rsvd_2;

				/* bit 319:288 - Notification Destination */

			u32	ndst;

		};

		u64 control;
@@ -88,4 +80,15 @@ static inline bool pi_test_sn(struct pi_desc *pi_desc) 
	return test_bit(POSTED_INTR_SN, (unsigned long *)&pi_desc->control);

}



/* Non-atomic helpers */

static inline void __pi_set_sn(struct pi_desc *pi_desc)

{

	pi_desc->notifications |= BIT(POSTED_INTR_SN);

}



static inline void __pi_clear_sn(struct pi_desc *pi_desc)

{

	pi_desc->notifications &= ~BIT(POSTED_INTR_SN);

}



#endif /* _X86_POSTED_INTR_H */

arch/x86/kvm/vmx/posted_intr.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

		__pi_clear_sn(&new);



		/*

		 * 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_test_sn(pi_desc), "PI descriptor SN field set before blocking");



	old.control = READ_ONCE(pi_desc->control);

	do {

arch/x86/kvm/vmx/vmx.c

+1 −1
Original line number Diff line number Diff line
@@ -4845,7 +4845,7 @@ 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;

	__pi_set_sn(&vmx->pi_desc);

}



static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)