From c813bb17f2b7166adb1c740ffc0d957b46271fa1 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 9 Feb 2016 17:01:33 +0000 Subject: [PATCH] KVM: arm/arm64: vgic-v2: Save maintenance interrupt state only if required Next on our list of useless accesses is the maintenance interrupt status registers (GICH_MISR, GICH_EISR{0,1}). It is pointless to save them if we haven't asked for a maintenance interrupt the first place, which can only happen for two reasons: - Underflow: GICH_HCR_UIE will be set, - EOI: GICH_LR_EOI will be set. These conditions can be checked on the in-memory copies of the regs. Should any of these two condition be valid, we must read GICH_MISR. We can then check for GICH_MISR_EOI, and only when set read GICH_EISR*. This means that in most case, we don't have to save them at all. Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- virt/kvm/arm/hyp/vgic-v2-sr.c | 54 ++++++++++++++++++++++++++++++----- 1 file changed, 47 insertions(+), 7 deletions(-) diff --git a/virt/kvm/arm/hyp/vgic-v2-sr.c b/virt/kvm/arm/hyp/vgic-v2-sr.c index aa0fdb89827f..0dd83d5ddb7e 100644 --- a/virt/kvm/arm/hyp/vgic-v2-sr.c +++ b/virt/kvm/arm/hyp/vgic-v2-sr.c @@ -21,6 +21,49 @@ #include +static void __hyp_text save_maint_int_state(struct kvm_vcpu *vcpu, + void __iomem *base) +{ + struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2; + int nr_lr = vcpu->arch.vgic_cpu.nr_lr; + u32 eisr0, eisr1; + int i; + bool expect_mi; + + expect_mi = !!(cpu_if->vgic_hcr & GICH_HCR_UIE); + + for (i = 0; i < nr_lr; i++) { + if (!(vcpu->arch.vgic_cpu.live_lrs & (1UL << i))) + continue; + + expect_mi |= (!(cpu_if->vgic_lr[i] & GICH_LR_HW) && + (cpu_if->vgic_lr[i] & GICH_LR_EOI)); + } + + if (expect_mi) { + cpu_if->vgic_misr = readl_relaxed(base + GICH_MISR); + + if (cpu_if->vgic_misr & GICH_MISR_EOI) { + eisr0 = readl_relaxed(base + GICH_EISR0); + if (unlikely(nr_lr > 32)) + eisr1 = readl_relaxed(base + GICH_EISR1); + else + eisr1 = 0; + } else { + eisr0 = eisr1 = 0; + } + } else { + cpu_if->vgic_misr = 0; + eisr0 = eisr1 = 0; + } + +#ifdef CONFIG_CPU_BIG_ENDIAN + cpu_if->vgic_eisr = ((u64)eisr0 << 32) | eisr1; +#else + cpu_if->vgic_eisr = ((u64)eisr1 << 32) | eisr0; +#endif +} + /* vcpu is already in the HYP VA space */ void __hyp_text __vgic_v2_save_state(struct kvm_vcpu *vcpu) { @@ -28,7 +71,7 @@ void __hyp_text __vgic_v2_save_state(struct kvm_vcpu *vcpu) struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2; struct vgic_dist *vgic = &kvm->arch.vgic; void __iomem *base = kern_hyp_va(vgic->vctrl_base); - u32 eisr0, eisr1, elrsr0, elrsr1; + u32 elrsr0, elrsr1; int i, nr_lr; if (!base) @@ -38,26 +81,23 @@ void __hyp_text __vgic_v2_save_state(struct kvm_vcpu *vcpu) cpu_if->vgic_vmcr = readl_relaxed(base + GICH_VMCR); 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; + elrsr1 = 0; } #ifdef CONFIG_CPU_BIG_ENDIAN - 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; #endif + save_maint_int_state(vcpu, base); + 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)); -- 2.20.1