[PATCH v6 24/24] KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES

Eric Auger
2017-05-04T11:47:19Z

This patch adds a new attribute to GICV3 KVM device
KVM_DEV_ARM_VGIC_GRP_CTRL group. This allows userspace to
flush all GICR pending tables into guest RAM.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---
v5 -> v6:
- fix stored
- GICR_PEND/PROPBASER_ADDRESS were already introduced

v4 -> v5:
- move pending table save code/ctrl into VGICv3 instead of ITS
- remove useless gpa_t cast
- use the same optimization as in its_sync_lpi_pending_table

v3 -> v4:
- remove the wrong comment about locking
- pass kvm struct instead of its handle
- add comment about restore method
- remove GITR_PENDABASER.PTZ check
- continue if target_vcpu == NULL
- new locking strategy

v1 -> v2:
- do not care about the 1st KB which should be zeroed according to
the spec.
---
arch/arm/include/uapi/asm/kvm.h | 1 +
arch/arm64/include/uapi/asm/kvm.h | 1 +
include/linux/irqchip/arm-gic-v3.h | 1 +
virt/kvm/arm/vgic/vgic-kvm-device.c | 20 +++++++++++++++
virt/kvm/arm/vgic/vgic-v3.c | 51 +++++++++++++++++++++++++++++++++++++
virt/kvm/arm/vgic/vgic.h | 1 +
6 files changed, 75 insertions(+)

diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index 8e6563c..78fe803 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -202,6 +202,7 @@ struct kvm_arch_memory_slot {
#define KVM_DEV_ARM_VGIC_CTRL_INIT 0
#define KVM_DEV_ARM_ITS_SAVE_TABLES 1
#define KVM_DEV_ARM_ITS_RESTORE_TABLES 2
+#define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3

/* KVM_IRQ_LINE irq field index values */
#define KVM_ARM_IRQ_TYPE_SHIFT 24
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 1e35115..8a3758a 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -222,6 +222,7 @@ struct kvm_arch_memory_slot {
#define KVM_DEV_ARM_VGIC_CTRL_INIT 0
#define KVM_DEV_ARM_ITS_SAVE_TABLES 1
#define KVM_DEV_ARM_ITS_RESTORE_TABLES 2
+#define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3

/* Device Control API on vcpu fd */
#define KVM_ARM_VCPU_PMU_V3_CTRL 0
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index e09e5d7..347d26f 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -186,6 +186,7 @@
#define GICR_PENDBASER_RaWaWb GIC_BASER_CACHEABILITY(GICR_PENDBASER, INNER, RaWaWb)

#define GICR_PENDBASER_PTZ BIT_ULL(62)
+#define GICR_PENDBASER_ADDRESS(x) ((x) & GENMASK_ULL(51, 16))

/*
* Re-Distributor registers, offsets from SGI_base
diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index 859bfa8..d48743c 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -580,6 +580,24 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
reg = tmp32;
return vgic_v3_attr_regs_access(dev, attr, &reg, true);
}
+ case KVM_DEV_ARM_VGIC_GRP_CTRL: {
+ int ret;
+
+ switch (attr->attr) {
+ case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
+ mutex_lock(&dev->kvm->lock);
+
+ if (!lock_all_vcpus(dev->kvm)) {
+ mutex_unlock(&dev->kvm->lock);
+ return -EBUSY;
+ }
+ ret = vgic_v3_save_pending_tables(dev->kvm);
+ unlock_all_vcpus(dev->kvm);
+ mutex_unlock(&dev->kvm->lock);
+ return ret;
+ }
+ break;
+ }
}
return -ENXIO;
}
@@ -658,6 +676,8 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
switch (attr->attr) {
case KVM_DEV_ARM_VGIC_CTRL_INIT:
return 0;
+ case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
+ return 0;
}
}
return -ENXIO;
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 0d753ae..6ff6510 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -296,6 +296,57 @@ int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq)
return 0;
}

+/**
+ * vgic_its_save_pending_tables - Save the pending tables into guest RAM
+ * kvm lock and all vcpu lock must be held
+ */
+int vgic_v3_save_pending_tables(struct kvm *kvm)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ int last_byte_offset = -1;
+ struct vgic_irq *irq;
+ int ret;
+
+ list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+ int byte_offset, bit_nr;
+ struct kvm_vcpu *vcpu;
+ gpa_t pendbase, ptr;
+ bool stored;
+ u8 val;
+
+ vcpu = irq->target_vcpu;
+ if (!vcpu)
+ continue;
+
+ pendbase = GICR_PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
+
+ byte_offset = irq->intid / BITS_PER_BYTE;
+ bit_nr = irq->intid % BITS_PER_BYTE;
+ ptr = pendbase + byte_offset;
+
+ if (byte_offset != last_byte_offset) {
+ ret = kvm_read_guest(kvm, ptr, &val, 1);
+ if (ret)
+ return ret;
+ last_byte_offset = byte_offset;
+ }
+
+ stored = val & (1U << bit_nr);
+ if (stored == irq->pending_latch)
+ continue;
+
+ if (irq->pending_latch)
+ val |= 1 << bit_nr;
+ else
+ val &= ~(1 << bit_nr);
+
+ ret = kvm_write_guest(kvm, ptr, &val, 1);
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+
/* check for overlapping regions and for regions crossing the end of memory */
static bool vgic_v3_check_base(struct kvm *kvm)
{
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 92a8ca0..8de59a4 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -181,6 +181,7 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu);
int vgic_v3_probe(const struct gic_kvm_info *info);
int vgic_v3_map_resources(struct kvm *kvm);
int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq);
+int vgic_v3_save_pending_tables(struct kvm *kvm);
int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);

int vgic_register_its_iodevs(struct kvm *kvm);
--
2.5.5