[PATCH v6 03/39] KVM: arm64: Return early from kvm_finalize_sys_regs() if guest has run

Sascha Bischoff
2026-03-17T11:41:54Z

If the guest has already run, we have no business finalizing the
system register state - it is too late. Therefore, check early and
bail if the VM has already run.

Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
---
arch/arm64/kvm/sys_regs.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0acd10e50aaba..42c84b7900ff5 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -5659,11 +5659,14 @@ int kvm_finalize_sys_regs(struct kvm_vcpu *vcpu)

guard(mutex)(&kvm->arch.config_lock);

+ if (kvm_vm_has_ran_once(kvm))
+ return 0;
+
/*
* This hacks into the ID registers, so only perform it when the
* first vcpu runs, or the kvm_set_vm_id_reg() helper will scream.
*/
- if (!irqchip_in_kernel(kvm) && !kvm_vm_has_ran_once(kvm)) {
+ if (!irqchip_in_kernel(kvm)) {
u64 val;

val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1) & ~ID_AA64PFR0_EL1_GIC;
--
2.34.1