KVM: arm/arm64: The GIC is dead, long live the GIC

I don't think any single piece of the KVM/ARM code ever generated
as much hatred as the GIC emulation.

It was written by someone who had zero experience in modeling
hardware (me), was riddled with design flaws, should have been
scrapped and rewritten from scratch long before having a remote
chance of reaching mainline, and yet we supported it for a good
three years. No need to mention the names of those who suffered,
the git log is singing their praises.

Thankfully, we now have a much more maintainable implementation,
and we can safely put the grumpy old GIC to rest.

Fellow hackers, please raise your glass in memory of the GIC:

	The GIC is dead, long live the GIC!

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 0 insertions, 279 deletions

diff --git a/virt/kvm/arm/vgic-v3.c b/virt/kvm/arm/vgic-v3.c
deleted file mode 100644
index 75b02fa86436..000000000000
--- a/virt/kvm/arm/vgic-v3.c
+++ /dev/null
@@ -1,279 +0,0 @@
-/*
- * Copyright (C) 2013 ARM Limited, All Rights Reserved.
- * Author: Marc Zyngier <marc.zyngier@arm.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/cpu.h>
-#include <linux/kvm.h>
-#include <linux/kvm_host.h>
-#include <linux/interrupt.h>
-#include <linux/io.h>
-
-#include <linux/irqchip/arm-gic-v3.h>
-#include <linux/irqchip/arm-gic-common.h>
-
-#include <asm/kvm_emulate.h>
-#include <asm/kvm_arm.h>
-#include <asm/kvm_asm.h>
-#include <asm/kvm_mmu.h>
-
-static u32 ich_vtr_el2;
-
-static struct vgic_lr vgic_v3_get_lr(const struct kvm_vcpu *vcpu, int lr)
-{
-	struct vgic_lr lr_desc;
-	u64 val = vcpu->arch.vgic_cpu.vgic_v3.vgic_lr[lr];
-
-	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
-		lr_desc.irq = val & ICH_LR_VIRTUAL_ID_MASK;
-	else
-		lr_desc.irq = val & GICH_LR_VIRTUALID;
-
-	lr_desc.source = 0;
-	if (lr_desc.irq <= 15 &&
-	    vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
-		lr_desc.source = (val >> GICH_LR_PHYSID_CPUID_SHIFT) & 0x7;
-
-	lr_desc.state = 0;
-
-	if (val & ICH_LR_PENDING_BIT)
-		lr_desc.state |= LR_STATE_PENDING;
-	if (val & ICH_LR_ACTIVE_BIT)
-		lr_desc.state |= LR_STATE_ACTIVE;
-	if (val & ICH_LR_EOI)
-		lr_desc.state |= LR_EOI_INT;
-	if (val & ICH_LR_HW) {
-		lr_desc.state |= LR_HW;
-		lr_desc.hwirq = (val >> ICH_LR_PHYS_ID_SHIFT) & GENMASK(9, 0);
-	}
-
-	return lr_desc;
-}
-
-static void vgic_v3_set_lr(struct kvm_vcpu *vcpu, int lr,
-			   struct vgic_lr lr_desc)
-{
-	u64 lr_val;
-
-	lr_val = lr_desc.irq;
-
-	/*
-	 * Currently all guest IRQs are Group1, as Group0 would result
-	 * in a FIQ in the guest, which it wouldn't expect.
-	 * Eventually we want to make this configurable, so we may revisit
-	 * this in the future.
-	 */
-	switch (vcpu->kvm->arch.vgic.vgic_model) {
-	case KVM_DEV_TYPE_ARM_VGIC_V3:
-		lr_val |= ICH_LR_GROUP;
-		break;
-	case  KVM_DEV_TYPE_ARM_VGIC_V2:
-		if (lr_desc.irq < VGIC_NR_SGIS)
-			lr_val |= (u32)lr_desc.source << GICH_LR_PHYSID_CPUID_SHIFT;
-		break;
-	default:
-		BUG();
-	}
-
-	if (lr_desc.state & LR_STATE_PENDING)
-		lr_val |= ICH_LR_PENDING_BIT;
-	if (lr_desc.state & LR_STATE_ACTIVE)
-		lr_val |= ICH_LR_ACTIVE_BIT;
-	if (lr_desc.state & LR_EOI_INT)
-		lr_val |= ICH_LR_EOI;
-	if (lr_desc.state & LR_HW) {
-		lr_val |= ICH_LR_HW;
-		lr_val |= ((u64)lr_desc.hwirq) << ICH_LR_PHYS_ID_SHIFT;
-	}
-
-	vcpu->arch.vgic_cpu.vgic_v3.vgic_lr[lr] = lr_val;
-
-	if (!(lr_desc.state & LR_STATE_MASK))
-		vcpu->arch.vgic_cpu.vgic_v3.vgic_elrsr |= (1U << lr);
-	else
-		vcpu->arch.vgic_cpu.vgic_v3.vgic_elrsr &= ~(1U << lr);
-}
-
-static u64 vgic_v3_get_elrsr(const struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.vgic_cpu.vgic_v3.vgic_elrsr;
-}
-
-static u64 vgic_v3_get_eisr(const struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.vgic_cpu.vgic_v3.vgic_eisr;
-}
-
-static void vgic_v3_clear_eisr(struct kvm_vcpu *vcpu)
-{
-	vcpu->arch.vgic_cpu.vgic_v3.vgic_eisr = 0;
-}
-
-static u32 vgic_v3_get_interrupt_status(const struct kvm_vcpu *vcpu)
-{
-	u32 misr = vcpu->arch.vgic_cpu.vgic_v3.vgic_misr;
-	u32 ret = 0;
-
-	if (misr & ICH_MISR_EOI)
-		ret |= INT_STATUS_EOI;
-	if (misr & ICH_MISR_U)
-		ret |= INT_STATUS_UNDERFLOW;
-
-	return ret;
-}
-
-static void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
-{
-	u32 vmcr = vcpu->arch.vgic_cpu.vgic_v3.vgic_vmcr;
-
-	vmcrp->ctlr = (vmcr & ICH_VMCR_CTLR_MASK) >> ICH_VMCR_CTLR_SHIFT;
-	vmcrp->abpr = (vmcr & ICH_VMCR_BPR1_MASK) >> ICH_VMCR_BPR1_SHIFT;
-	vmcrp->bpr  = (vmcr & ICH_VMCR_BPR0_MASK) >> ICH_VMCR_BPR0_SHIFT;
-	vmcrp->pmr  = (vmcr & ICH_VMCR_PMR_MASK) >> ICH_VMCR_PMR_SHIFT;
-}
-
-static void vgic_v3_enable_underflow(struct kvm_vcpu *vcpu)
-{
-	vcpu->arch.vgic_cpu.vgic_v3.vgic_hcr |= ICH_HCR_UIE;
-}
-
-static void vgic_v3_disable_underflow(struct kvm_vcpu *vcpu)
-{
-	vcpu->arch.vgic_cpu.vgic_v3.vgic_hcr &= ~ICH_HCR_UIE;
-}
-
-static void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
-{
-	u32 vmcr;
-
-	vmcr  = (vmcrp->ctlr << ICH_VMCR_CTLR_SHIFT) & ICH_VMCR_CTLR_MASK;
-	vmcr |= (vmcrp->abpr << ICH_VMCR_BPR1_SHIFT) & ICH_VMCR_BPR1_MASK;
-	vmcr |= (vmcrp->bpr << ICH_VMCR_BPR0_SHIFT) & ICH_VMCR_BPR0_MASK;
-	vmcr |= (vmcrp->pmr << ICH_VMCR_PMR_SHIFT) & ICH_VMCR_PMR_MASK;
-
-	vcpu->arch.vgic_cpu.vgic_v3.vgic_vmcr = vmcr;
-}
-
-static void vgic_v3_enable(struct kvm_vcpu *vcpu)
-{
-	struct vgic_v3_cpu_if *vgic_v3 = &vcpu->arch.vgic_cpu.vgic_v3;
-
-	/*
-	 * By forcing VMCR to zero, the GIC will restore the binary
-	 * points to their reset values. Anything else resets to zero
-	 * anyway.
-	 */
-	vgic_v3->vgic_vmcr = 0;
-	vgic_v3->vgic_elrsr = ~0;
-
-	/*
-	 * If we are emulating a GICv3, we do it in an non-GICv2-compatible
-	 * way, so we force SRE to 1 to demonstrate this to the guest.
-	 * This goes with the spec allowing the value to be RAO/WI.
-	 */
-	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
-		vgic_v3->vgic_sre = ICC_SRE_EL1_SRE;
-	else
-		vgic_v3->vgic_sre = 0;
-
-	/* Get the show on the road... */
-	vgic_v3->vgic_hcr = ICH_HCR_EN;
-}
-
-static const struct vgic_ops vgic_v3_ops = {
-	.get_lr			= vgic_v3_get_lr,
-	.set_lr			= vgic_v3_set_lr,
-	.get_elrsr		= vgic_v3_get_elrsr,
-	.get_eisr		= vgic_v3_get_eisr,
-	.clear_eisr		= vgic_v3_clear_eisr,
-	.get_interrupt_status	= vgic_v3_get_interrupt_status,
-	.enable_underflow	= vgic_v3_enable_underflow,
-	.disable_underflow	= vgic_v3_disable_underflow,
-	.get_vmcr		= vgic_v3_get_vmcr,
-	.set_vmcr		= vgic_v3_set_vmcr,
-	.enable			= vgic_v3_enable,
-};
-
-static struct vgic_params vgic_v3_params;
-
-static void vgic_cpu_init_lrs(void *params)
-{
-	kvm_call_hyp(__vgic_v3_init_lrs);
-}
-
-/**
- * vgic_v3_probe - probe for a GICv3 compatible interrupt controller
- * @gic_kvm_info:	pointer to the GIC description
- * @ops:		address of a pointer to the GICv3 operations
- * @params:		address of a pointer to HW-specific parameters
- *
- * Returns 0 if a GICv3 has been found, with the low level operations
- * in *ops and the HW parameters in *params. Returns an error code
- * otherwise.
- */
-int vgic_v3_probe(const struct gic_kvm_info *gic_kvm_info,
-		  const struct vgic_ops **ops,
-		  const struct vgic_params **params)
-{
-	int ret = 0;
-	struct vgic_params *vgic = &vgic_v3_params;
-	const struct resource *vcpu_res = &gic_kvm_info->vcpu;
-
-	vgic->maint_irq = gic_kvm_info->maint_irq;
-
-	ich_vtr_el2 = kvm_call_hyp(__vgic_v3_get_ich_vtr_el2);
-
-	/*
-	 * The ListRegs field is 5 bits, but there is a architectural
-	 * maximum of 16 list registers. Just ignore bit 4...
-	 */
-	vgic->nr_lr = (ich_vtr_el2 & 0xf) + 1;
-	vgic->can_emulate_gicv2 = false;
-
-	if (!vcpu_res->start) {
-		kvm_info("GICv3: no GICV resource entry\n");
-		vgic->vcpu_base = 0;
-	} else if (!PAGE_ALIGNED(vcpu_res->start)) {
-		pr_warn("GICV physical address 0x%llx not page aligned\n",
-			(unsigned long long)vcpu_res->start);
-		vgic->vcpu_base = 0;
-	} else if (!PAGE_ALIGNED(resource_size(vcpu_res))) {
-		pr_warn("GICV size 0x%llx not a multiple of page size 0x%lx\n",
-			(unsigned long long)resource_size(vcpu_res),
-			PAGE_SIZE);
-	} else {
-		vgic->vcpu_base = vcpu_res->start;
-		vgic->can_emulate_gicv2 = true;
-		kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
-					KVM_DEV_TYPE_ARM_VGIC_V2);
-	}
-	if (vgic->vcpu_base == 0)
-		kvm_info("disabling GICv2 emulation\n");
-	kvm_register_device_ops(&kvm_arm_vgic_v3_ops, KVM_DEV_TYPE_ARM_VGIC_V3);
-
-	vgic->vctrl_base = NULL;
-	vgic->type = VGIC_V3;
-	vgic->max_gic_vcpus = VGIC_V3_MAX_CPUS;
-
-	kvm_info("GICV base=0x%llx, IRQ=%d\n",
-		 vgic->vcpu_base, vgic->maint_irq);
-
-	on_each_cpu(vgic_cpu_init_lrs, vgic, 1);
-
-	*ops = &vgic_v3_ops;
-	*params = vgic;
-
-	return ret;
-}