[PATCH v4 07/16] KVM: arm64: nv: Sanitise ICH_HCR_EL2 accesses

Marc Zyngier
2025-02-25T17:29:47Z

As ICH_HCR_EL2 is a VNCR accessor when runnintg NV, add some
sanitising to what gets written. Crucially, mark TDIR as RES0
if the HW doesn't support it (unlikely, but hey...), as well
as anything GICv4 related, since we only expose a GICv3 to the
uest.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/nested.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
index 0c9387d2f5070..7c8f39070a503 100644
--- a/arch/arm64/kvm/nested.c
+++ b/arch/arm64/kvm/nested.c
@@ -1290,6 +1290,15 @@ int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu)
res0 |= GENMASK(11, 8);
set_sysreg_masks(kvm, CNTHCTL_EL2, res0, res1);

+ /* ICH_HCR_EL2 */
+ res0 = ICH_HCR_EL2_RES0;
+ res1 = ICH_HCR_EL2_RES1;
+ if (!(kvm_vgic_global_state.ich_vtr_el2 & ICH_VTR_EL2_TDS))
+ res0 |= ICH_HCR_EL2_TDIR;
+ /* No GICv4 is presented to the guest */
+ res0 |= ICH_HCR_EL2_DVIM | ICH_HCR_EL2_vSGIEOICount;
+ set_sysreg_masks(kvm, ICH_HCR_EL2, res0, res1);
+
out:
for (enum vcpu_sysreg sr = __SANITISED_REG_START__; sr < NR_SYS_REGS; sr++)
(void)__vcpu_sys_reg(vcpu, sr);
--
2.39.2