KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES

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>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 9ae8adddff69..54dee725da18 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -278,6 +278,57 @@ retry:
 	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)
 {