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Commit f7035ce9 authored by Paul Mackerras's avatar Paul Mackerras Committed by Michael Ellerman
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KVM: PPC: Book3S HV: Move interrupt delivery on guest entry to C code 



This is based on a patch by Suraj Jitindar Singh.

This moves the code in book3s_hv_rmhandlers.S that generates an
external, decrementer or privileged doorbell interrupt just before
entering the guest to C code in book3s_hv_builtin.c.  This is to
make future maintenance and modification easier.  The algorithm
expressed in the C code is almost identical to the previous
algorithm.

Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 966eba93

arch/powerpc/include/asm/kvm_ppc.h

+1 −0
Original line number Diff line number Diff line
@@ -650,6 +650,7 @@ int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server, 
                    unsigned long mfrr);

int kvmppc_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr);

int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr);

void kvmppc_guest_entry_inject_int(struct kvm_vcpu *vcpu);



/*

 * Host-side operations we want to set up while running in real

arch/powerpc/kvm/book3s_hv.c

+1 −2
Original line number Diff line number Diff line
@@ -730,8 +730,7 @@ static bool kvmppc_doorbell_pending(struct kvm_vcpu *vcpu) 
	/*

	 * Ensure that the read of vcore->dpdes comes after the read

	 * of vcpu->doorbell_request.  This barrier matches the

	 * lwsync in book3s_hv_rmhandlers.S just before the

	 * fast_guest_return label.

	 * smb_wmb() in kvmppc_guest_entry_inject().

	 */

	smp_rmb();

	vc = vcpu->arch.vcore;

arch/powerpc/kvm/book3s_hv_builtin.c

+48 −0
Original line number Diff line number Diff line
@@ -729,3 +729,51 @@ void kvmhv_p9_restore_lpcr(struct kvm_split_mode *sip) 
	smp_mb();

	local_paca->kvm_hstate.kvm_split_mode = NULL;

}



/*

 * Is there a PRIV_DOORBELL pending for the guest (on POWER9)?

 * Can we inject a Decrementer or a External interrupt?

 */

void kvmppc_guest_entry_inject_int(struct kvm_vcpu *vcpu)

{

	int ext;

	unsigned long vec = 0;

	unsigned long lpcr;



	/* Insert EXTERNAL bit into LPCR at the MER bit position */

	ext = (vcpu->arch.pending_exceptions >> BOOK3S_IRQPRIO_EXTERNAL) & 1;

	lpcr = mfspr(SPRN_LPCR);

	lpcr |= ext << LPCR_MER_SH;

	mtspr(SPRN_LPCR, lpcr);

	isync();



	if (vcpu->arch.shregs.msr & MSR_EE) {

		if (ext) {

			vec = BOOK3S_INTERRUPT_EXTERNAL;

		} else {

			long int dec = mfspr(SPRN_DEC);

			if (!(lpcr & LPCR_LD))

				dec = (int) dec;

			if (dec < 0)

				vec = BOOK3S_INTERRUPT_DECREMENTER;

		}

	}

	if (vec) {

		unsigned long msr, old_msr = vcpu->arch.shregs.msr;



		kvmppc_set_srr0(vcpu, kvmppc_get_pc(vcpu));

		kvmppc_set_srr1(vcpu, old_msr);

		kvmppc_set_pc(vcpu, vec);

		msr = vcpu->arch.intr_msr;

		if (MSR_TM_ACTIVE(old_msr))

			msr |= MSR_TS_S;

		vcpu->arch.shregs.msr = msr;

	}



	if (vcpu->arch.doorbell_request) {

		mtspr(SPRN_DPDES, 1);

		vcpu->arch.vcore->dpdes = 1;

		smp_wmb();

		vcpu->arch.doorbell_request = 0;

	}

}

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+17 −53
Original line number Diff line number Diff line
@@ -1101,13 +1101,20 @@ no_xive: 
#endif /* CONFIG_KVM_XICS */



deliver_guest_interrupt:

	ld	r6, VCPU_CTR(r4)

	ld	r7, VCPU_XER(r4)



	mtctr	r6

	mtxer	r7



kvmppc_cede_reentry:		/* r4 = vcpu, r13 = paca */

	/* Check if we can deliver an external or decrementer interrupt now */

	ld	r0, VCPU_PENDING_EXC(r4)

BEGIN_FTR_SECTION

	/* On POWER9, also check for emulated doorbell interrupt */

	lbz	r3, VCPU_DBELL_REQ(r4)

	or	r0, r0, r3

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)

	cmpdi	r0, 0

	beq	71f

	mr	r3, r4

	bl	kvmppc_guest_entry_inject_int

	ld	r4, HSTATE_KVM_VCPU(r13)

71:

	ld	r10, VCPU_PC(r4)

	ld	r11, VCPU_MSR(r4)

	ld	r6, VCPU_SRR0(r4)
@@ -1120,53 +1127,10 @@ kvmppc_cede_reentry: /* r4 = vcpu, r13 = paca */ 
	rotldi	r11, r11, 1 + MSR_HV_LG

	ori	r11, r11, MSR_ME



	/* Check if we can deliver an external or decrementer interrupt now */

	ld	r0, VCPU_PENDING_EXC(r4)

	rldicl	r0, r0, 64 - BOOK3S_IRQPRIO_EXTERNAL, 63

	cmpdi	cr1, r0, 0

	andi.	r8, r11, MSR_EE

	mfspr	r8, SPRN_LPCR

	/* Insert EXTERNAL bit into LPCR at the MER bit position */

	rldimi	r8, r0, LPCR_MER_SH, 63 - LPCR_MER_SH

	mtspr	SPRN_LPCR, r8

	isync

	beq	5f

	li	r0, BOOK3S_INTERRUPT_EXTERNAL

	bne	cr1, 12f

	mfspr	r0, SPRN_DEC

BEGIN_FTR_SECTION

	/* On POWER9 check whether the guest has large decrementer enabled */

	andis.	r8, r8, LPCR_LD@h

	bne	15f

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)

	extsw	r0, r0

15:	cmpdi	r0, 0

	li	r0, BOOK3S_INTERRUPT_DECREMENTER

	bge	5f



12:	mtspr	SPRN_SRR0, r10

	mr	r10,r0

	mtspr	SPRN_SRR1, r11

	mr	r9, r4

	bl	kvmppc_msr_interrupt

5:

BEGIN_FTR_SECTION

	b	fast_guest_return

END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)

	/* On POWER9, check for pending doorbell requests */

	lbz	r0, VCPU_DBELL_REQ(r4)

	cmpwi	r0, 0

	beq	fast_guest_return

	ld	r5, HSTATE_KVM_VCORE(r13)

	/* Set DPDES register so the CPU will take a doorbell interrupt */

	li	r0, 1

	mtspr	SPRN_DPDES, r0

	std	r0, VCORE_DPDES(r5)

	/* Make sure other cpus see vcore->dpdes set before dbell req clear */

	lwsync

	/* Clear the pending doorbell request */

	li	r0, 0

	stb	r0, VCPU_DBELL_REQ(r4)

	ld	r6, VCPU_CTR(r4)

	ld	r7, VCPU_XER(r4)

	mtctr	r6

	mtxer	r7



/*

 * Required state: