From 59f00ff9afc028053fa9281407627e95008ebd5c Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 2 Feb 2016 19:35:34 +0000 Subject: KVM: arm/arm64: vgic-v2: Avoid accessing GICH registers GICv2 registers are *slow*. As in "terrifyingly slow". Which is bad. But we're equaly bad, as we make a point in accessing them even if we don't have any interrupt in flight. A good solution is to first find out if we have anything useful to write into the GIC, and if we don't, to simply not do it. This involves tracking which LRs actually have something valid there. Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- virt/kvm/arm/hyp/vgic-v2-sr.c | 72 ++++++++++++++++++++++++++++++------------- 1 file changed, 50 insertions(+), 22 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/hyp/vgic-v2-sr.c b/virt/kvm/arm/hyp/vgic-v2-sr.c index 9514a7d..aa0fdb8 100644 --- a/virt/kvm/arm/hyp/vgic-v2-sr.c +++ b/virt/kvm/arm/hyp/vgic-v2-sr.c @@ -36,28 +36,41 @@ void __hyp_text __vgic_v2_save_state(struct kvm_vcpu *vcpu) nr_lr = vcpu->arch.vgic_cpu.nr_lr; cpu_if->vgic_vmcr = readl_relaxed(base + GICH_VMCR); - cpu_if->vgic_misr = readl_relaxed(base + GICH_MISR); - eisr0 = readl_relaxed(base + GICH_EISR0); - elrsr0 = readl_relaxed(base + GICH_ELRSR0); - if (unlikely(nr_lr > 32)) { - eisr1 = readl_relaxed(base + GICH_EISR1); - elrsr1 = readl_relaxed(base + GICH_ELRSR1); - } else { - eisr1 = elrsr1 = 0; - } + + if (vcpu->arch.vgic_cpu.live_lrs) { + eisr0 = readl_relaxed(base + GICH_EISR0); + elrsr0 = readl_relaxed(base + GICH_ELRSR0); + cpu_if->vgic_misr = readl_relaxed(base + GICH_MISR); + cpu_if->vgic_apr = readl_relaxed(base + GICH_APR); + + if (unlikely(nr_lr > 32)) { + eisr1 = readl_relaxed(base + GICH_EISR1); + elrsr1 = readl_relaxed(base + GICH_ELRSR1); + } else { + eisr1 = elrsr1 = 0; + } + #ifdef CONFIG_CPU_BIG_ENDIAN - cpu_if->vgic_eisr = ((u64)eisr0 << 32) | eisr1; - cpu_if->vgic_elrsr = ((u64)elrsr0 << 32) | elrsr1; + cpu_if->vgic_eisr = ((u64)eisr0 << 32) | eisr1; + cpu_if->vgic_elrsr = ((u64)elrsr0 << 32) | elrsr1; #else - cpu_if->vgic_eisr = ((u64)eisr1 << 32) | eisr0; - cpu_if->vgic_elrsr = ((u64)elrsr1 << 32) | elrsr0; + cpu_if->vgic_eisr = ((u64)eisr1 << 32) | eisr0; + cpu_if->vgic_elrsr = ((u64)elrsr1 << 32) | elrsr0; #endif - cpu_if->vgic_apr = readl_relaxed(base + GICH_APR); - writel_relaxed(0, base + GICH_HCR); + for (i = 0; i < nr_lr; i++) + if (vcpu->arch.vgic_cpu.live_lrs & (1UL << i)) + cpu_if->vgic_lr[i] = readl_relaxed(base + GICH_LR0 + (i * 4)); - for (i = 0; i < nr_lr; i++) - cpu_if->vgic_lr[i] = readl_relaxed(base + GICH_LR0 + (i * 4)); + writel_relaxed(0, base + GICH_HCR); + + vcpu->arch.vgic_cpu.live_lrs = 0; + } else { + cpu_if->vgic_eisr = 0; + cpu_if->vgic_elrsr = ~0UL; + cpu_if->vgic_misr = 0; + cpu_if->vgic_apr = 0; + } } /* vcpu is already in the HYP VA space */ @@ -68,15 +81,30 @@ void __hyp_text __vgic_v2_restore_state(struct kvm_vcpu *vcpu) struct vgic_dist *vgic = &kvm->arch.vgic; void __iomem *base = kern_hyp_va(vgic->vctrl_base); int i, nr_lr; + u64 live_lrs = 0; if (!base) return; - writel_relaxed(cpu_if->vgic_hcr, base + GICH_HCR); - writel_relaxed(cpu_if->vgic_vmcr, base + GICH_VMCR); - writel_relaxed(cpu_if->vgic_apr, base + GICH_APR); - nr_lr = vcpu->arch.vgic_cpu.nr_lr; + for (i = 0; i < nr_lr; i++) - writel_relaxed(cpu_if->vgic_lr[i], base + GICH_LR0 + (i * 4)); + if (cpu_if->vgic_lr[i] & GICH_LR_STATE) + live_lrs |= 1UL << i; + + if (live_lrs) { + writel_relaxed(cpu_if->vgic_hcr, base + GICH_HCR); + writel_relaxed(cpu_if->vgic_apr, base + GICH_APR); + for (i = 0; i < nr_lr; i++) { + u32 val = 0; + + if (live_lrs & (1UL << i)) + val = cpu_if->vgic_lr[i]; + + writel_relaxed(val, base + GICH_LR0 + (i * 4)); + } + } + + writel_relaxed(cpu_if->vgic_vmcr, base + GICH_VMCR); + vcpu->arch.vgic_cpu.live_lrs = live_lrs; } -- cgit v1.1