linux-kernel - [PATCH v4 19/20] KVM: arm64: GICv4.1: Allow non-trapping WFI when using HW SGIs

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Date:   Fri, 14 Feb 2020 14:57:35 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Jason Cooper <jason@...edaemon.net>,
        Robert Richter <rrichter@...vell.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Zenghui Yu <yuzenghui@...wei.com>,
        Eric Auger <eric.auger@...hat.com>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>
Subject: [PATCH v4 19/20] KVM: arm64: GICv4.1: Allow non-trapping WFI when using HW SGIs

Just like for VLPIs, it is beneficial to avoid trapping on WFI when the
vcpu is using the GICv4.1 SGIs.

Add such a check to vcpu_clear_wfx_traps().

Signed-off-by: Marc Zyngier <maz@...nel.org>
---
 arch/arm64/include/asm/kvm_emulate.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 688c63412cc2..755654c839e2 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -89,7 +89,8 @@ static inline unsigned long *vcpu_hcr(struct kvm_vcpu *vcpu)
 static inline void vcpu_clear_wfx_traps(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.hcr_el2 &= ~HCR_TWE;
-	if (atomic_read(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count))
+	if (atomic_read(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count) ||
+	    vcpu->kvm->arch.vgic.nassgireq)
 		vcpu->arch.hcr_el2 &= ~HCR_TWI;
 	else
 		vcpu->arch.hcr_el2 |= HCR_TWI;
-- 
2.20.1