Commit 23bde34771f1 ("KVM: arm64: vgic-v3: Drop the
reporting of GICR_TYPER.Last for userspace") temporarily fixed
a bug identified when attempting to access the GICR_TYPER
register before the redistributor region setting but dropped
the support of the LAST bit. Emulating the GICR_TYPER.Last bit
still makes sense for architecture compliance.
This patch restores its support (if the redistributor region
was set) while keeping the code safe.
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
arch/arm64/kvm/vgic/vgic-mmio-v3.c | 7 ++++++-
include/kvm/arm_vgic.h | 1 +
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
index 987e366c8000..7ff23c153128 100644
--- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
@@ -277,6 +277,8 @@ static unsigned long vgic_uaccess_read_v3r_typer(struct kvm_vcpu *vcpu,
gpa_t addr, unsigned int len)
{
unsigned long mpidr = kvm_vcpu_get_mpidr_aff(vcpu);
+ struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+ struct vgic_redist_region *rdreg = vgic_cpu->rdreg;
int target_vcpu_id = vcpu->vcpu_id;
u64 value;
@@ -286,7 +288,9 @@ static unsigned long vgic_uaccess_read_v3r_typer(struct kvm_vcpu *vcpu,
if (vgic_has_its(vcpu->kvm))
value |= GICR_TYPER_PLPIS;
- /* reporting of the Last bit is not supported for userspace */
+ if (rdreg && (vgic_cpu->rdreg_index == (rdreg->free_index - 1)))
+ value |= GICR_TYPER_LAST;
+
return extract_bytes(value, addr & 7, len);
}
@@ -714,6 +718,7 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
return -EINVAL;
vgic_cpu->rdreg = rdreg;
+ vgic_cpu->rdreg_index = rdreg->free_index;
rd_base = rdreg->base + rdreg->free_index * KVM_VGIC_V3_REDIST_SIZE;
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 3d74f1060bd1..ec621180ef09 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -322,6 +322,7 @@ struct vgic_cpu {
*/
struct vgic_io_device rd_iodev;
struct vgic_redist_region *rdreg;
+ u32 rdreg_index;
/* Contains the attributes and gpa of the LPI pending tables. */
u64 pendbaser;
--
2.21.3
