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Commit 2267ea76 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Paul Mackerras
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KVM: PPC: Book3S HV: Don't use existing "prodded" flag for XIVE escalations 



The prodded flag is only cleared at the beginning of H_CEDE,
so every time we have an escalation, we will cause the *next*
H_CEDE to return immediately.

Instead use a dedicated "irq_pending" flag to indicate that
a guest interrupt is pending for the VCPU. We don't reuse the
existing exception bitmap so as to avoid expensive atomic ops.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent bf4159da

arch/powerpc/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -709,6 +709,7 @@ struct kvm_vcpu_arch { 
	u8 ceded;

	u8 prodded;

	u8 doorbell_request;

	u8 irq_pending; /* Used by XIVE to signal pending guest irqs */

	u32 last_inst;



	struct swait_queue_head *wqp;

arch/powerpc/kernel/asm-offsets.c

+1 −0
Original line number Diff line number Diff line
@@ -514,6 +514,7 @@ int main(void) 
	OFFSET(VCPU_PENDING_EXC, kvm_vcpu, arch.pending_exceptions);

	OFFSET(VCPU_CEDED, kvm_vcpu, arch.ceded);

	OFFSET(VCPU_PRODDED, kvm_vcpu, arch.prodded);

	OFFSET(VCPU_IRQ_PENDING, kvm_vcpu, arch.irq_pending);

	OFFSET(VCPU_DBELL_REQ, kvm_vcpu, arch.doorbell_request);

	OFFSET(VCPU_MMCR, kvm_vcpu, arch.mmcr);

	OFFSET(VCPU_PMC, kvm_vcpu, arch.pmc);

arch/powerpc/kvm/book3s_hv.c

+1 −1
Original line number Diff line number Diff line
@@ -2999,7 +2999,7 @@ static inline bool xive_interrupt_pending(struct kvm_vcpu *vcpu) 
{

	if (!xive_enabled())

		return false;

	return vcpu->arch.xive_saved_state.pipr <

	return vcpu->arch.irq_pending || vcpu->arch.xive_saved_state.pipr <

		vcpu->arch.xive_saved_state.cppr;

}

#else

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+10 −0
Original line number Diff line number Diff line
@@ -1035,6 +1035,16 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300) 
	li	r9, 1

	stw	r9, VCPU_XIVE_PUSHED(r4)

	eieio



	/*

	 * We clear the irq_pending flag. There is a small chance of a

	 * race vs. the escalation interrupt happening on another

	 * processor setting it again, but the only consequence is to

	 * cause a spurrious wakeup on the next H_CEDE which is not an

	 * issue.

	 */

	li	r0,0

	stb	r0, VCPU_IRQ_PENDING(r4)

no_xive:

#endif /* CONFIG_KVM_XICS */

arch/powerpc/kvm/book3s_xive.c

+1 −2
Original line number Diff line number Diff line
@@ -84,8 +84,7 @@ static irqreturn_t xive_esc_irq(int irq, void *data) 
{

	struct kvm_vcpu *vcpu = data;



	/* We use the existing H_PROD mechanism to wake up the target */

	vcpu->arch.prodded = 1;

	vcpu->arch.irq_pending = 1;

	smp_mb();

	if (vcpu->arch.ceded)

		kvmppc_fast_vcpu_kick(vcpu);