[PATCH v6 19/20] arm/arm64: KVM: enable kernel side of GICv3 emulation
Andre Przywara
andre.przywara at arm.com
Fri Jan 9 03:54:37 PST 2015
With all the necessary GICv3 emulation code in place, we can now
connect the code to the GICv3 backend in the kernel.
The LR register handling is different depending on the emulated GIC
model, so provide different implementations for each.
Also allow non-v2-compatible GICv3 implementations (which don't
provide MMIO regions for the virtual CPU interface in the DT), but
restrict those hosts to support GICv3 guests only.
If the device tree provides a GICv2 compatible GICV resource entry,
but that one is faulty, just disable the GICv2 emulation and let the
user use at least the GICv3 emulation for guests.
Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
Changelog v5...v6:
- allow GICv3 emulation in case of invalid GICv2 DT compat entries
- use new kvm_check_device_type()
Changelog v4...v5:
- minor whitespace and comments fixes
Changelog v3...v4:
- handle differences between GICv2-on-v3 and GICv3-on-v3 in existing functions
- remove init_*_emul() functions
- remove max_vcpus setting (done in earlier patches now)
- adapt to new vgic_v<n>_init_emulation behaviour
virt/kvm/arm/vgic-v3.c | 74 ++++++++++++++++++++++++++++++++----------------
virt/kvm/arm/vgic.c | 9 ++++++
2 files changed, 58 insertions(+), 25 deletions(-)
diff --git a/virt/kvm/arm/vgic-v3.c b/virt/kvm/arm/vgic-v3.c
index 5249048..d221b25 100644
--- a/virt/kvm/arm/vgic-v3.c
+++ b/virt/kvm/arm/vgic-v3.c
@@ -34,6 +34,7 @@
#define GICH_LR_VIRTUALID (0x3ffUL << 0)
#define GICH_LR_PHYSID_CPUID_SHIFT (10)
#define GICH_LR_PHYSID_CPUID (7UL << GICH_LR_PHYSID_CPUID_SHIFT)
+#define ICH_LR_VIRTUALID_MASK (BIT_ULL(32) - 1)
/*
* LRs are stored in reverse order in memory. make sure we index them
@@ -48,12 +49,17 @@ 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_INDEX(lr)];
- lr_desc.irq = val & GICH_LR_VIRTUALID;
- if (lr_desc.irq <= 15)
- lr_desc.source = (val >> GICH_LR_PHYSID_CPUID_SHIFT) & 0x7;
+ if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
+ lr_desc.irq = val & ICH_LR_VIRTUALID_MASK;
else
- lr_desc.source = 0;
- lr_desc.state = 0;
+ 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;
@@ -68,8 +74,20 @@ static struct vgic_lr vgic_v3_get_lr(const struct kvm_vcpu *vcpu, int lr)
static void vgic_v3_set_lr(struct kvm_vcpu *vcpu, int lr,
struct vgic_lr lr_desc)
{
- u64 lr_val = (((u32)lr_desc.source << GICH_LR_PHYSID_CPUID_SHIFT) |
- lr_desc.irq);
+ 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.
+ */
+ if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
+ lr_val |= ICH_LR_GROUP;
+ else
+ lr_val |= (u32)lr_desc.source << GICH_LR_PHYSID_CPUID_SHIFT;
if (lr_desc.state & LR_STATE_PENDING)
lr_val |= ICH_LR_PENDING_BIT;
@@ -154,7 +172,15 @@ static void vgic_v3_enable(struct kvm_vcpu *vcpu)
*/
vgic_v3->vgic_vmcr = 0;
- vgic_v3->vgic_sre = 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;
@@ -215,28 +241,26 @@ int vgic_v3_probe(struct device_node *vgic_node,
gicv_idx += 3; /* Also skip GICD, GICC, GICH */
if (of_address_to_resource(vgic_node, gicv_idx, &vcpu_res)) {
- kvm_err("Cannot obtain GICV region\n");
- ret = -ENXIO;
- goto out;
- }
-
- if (!PAGE_ALIGNED(vcpu_res.start)) {
- kvm_err("GICV physical address 0x%llx not page aligned\n",
+ 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);
- ret = -ENXIO;
- goto out;
- }
-
- if (!PAGE_ALIGNED(resource_size(&vcpu_res))) {
- kvm_err("GICV size 0x%llx not a multiple of page size 0x%lx\n",
+ 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);
- ret = -ENXIO;
- goto out;
+ vgic->vcpu_base = 0;
+ } else {
+ vgic->vcpu_base = vcpu_res.start;
+ kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
+ KVM_DEV_TYPE_ARM_VGIC_V2);
}
- 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->vcpu_base = vcpu_res.start;
vgic->vctrl_base = NULL;
vgic->type = VGIC_V3;
vgic->max_gic_vcpus = KVM_MAX_VCPUS;
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index e0a23da..e474bd2 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1544,6 +1544,11 @@ static int init_vgic_model(struct kvm *kvm, int type)
case KVM_DEV_TYPE_ARM_VGIC_V2:
ret = vgic_v2_init_emulation(kvm);
break;
+#ifdef CONFIG_ARM_GIC_V3
+ case KVM_DEV_TYPE_ARM_VGIC_V3:
+ ret = vgic_v3_init_emulation(kvm);
+ break;
+#endif
default:
ret = -ENODEV;
break;
@@ -1573,6 +1578,10 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
goto out;
}
+ ret = kvm_check_device_type(type);
+ if (ret != -EEXIST)
+ goto out;
+
/*
* Any time a vcpu is run, vcpu_load is called which tries to grab the
* vcpu->mutex. By grabbing the vcpu->mutex of all VCPUs we ensure
--
1.7.9.5
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