arm/arm64: KVM: make the value of ICC_SRE_EL1 a per-VM variable

ICC_SRE_EL1 is a system register allowing msr/mrs accesses to the
GIC CPU interface for EL1 (guests). Currently we force it to 0, but
for proper GICv3 support we have to allow guests to use it (depending
on their selected virtual GIC model).
So add ICC_SRE_EL1 to the list of saved/restored registers on a
world switch, but actually disallow a guest to change it by only
restoring a fixed, once-initialized value.
This value depends on the GIC model userland has chosen for a guest.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 1c0e9dbabe6d..ff04afd0d901 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -245,6 +245,7 @@ struct vgic_v3_cpu_if {
 #ifdef CONFIG_ARM_GIC_V3
         u32             vgic_hcr;
         u32             vgic_vmcr;
+        u32             vgic_sre;       /* Restored only, change ignored */
         u32             vgic_misr;      /* Saved only */
         u32             vgic_eisr;      /* Saved only */
         u32             vgic_elrsr;     /* Saved only */