1 files changed, 18 insertions, 2 deletions

diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index a3ad7ff95c9b..0a4283ed9aa7 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -229,7 +229,15 @@ static unsigned long vgic_mmio_read_vcpuif(struct kvm_vcpu *vcpu,
                 val = vmcr.ctlr;
                 break;
         case GIC_CPU_PRIMASK:
-                val = vmcr.pmr;
+                /*
+                 * Our KVM_DEV_TYPE_ARM_VGIC_V2 device ABI exports the
+                 * the PMR field as GICH_VMCR.VMPriMask rather than
+                 * GICC_PMR.Priority, so we expose the upper five bits of
+                 * priority mask to userspace using the lower bits in the
+                 * unsigned long.
+                 */
+                val = (vmcr.pmr & GICV_PMR_PRIORITY_MASK) >>
+                        GICV_PMR_PRIORITY_SHIFT;
                 break;
         case GIC_CPU_BINPOINT:
                 val = vmcr.bpr;
@@ -262,7 +270,15 @@ static void vgic_mmio_write_vcpuif(struct kvm_vcpu *vcpu,
                 vmcr.ctlr = val;
                 break;
         case GIC_CPU_PRIMASK:
-                vmcr.pmr = val;
+                /*
+                 * Our KVM_DEV_TYPE_ARM_VGIC_V2 device ABI exports the
+                 * the PMR field as GICH_VMCR.VMPriMask rather than
+                 * GICC_PMR.Priority, so we expose the upper five bits of
+                 * priority mask to userspace using the lower bits in the
+                 * unsigned long.
+                 */
+                vmcr.pmr = (val << GICV_PMR_PRIORITY_SHIFT) &
+                        GICV_PMR_PRIORITY_MASK;
                 break;
         case GIC_CPU_BINPOINT:
                 vmcr.bpr = val;