From: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
In AArch64/AArch32, the virtual counter uses a fixed virtual offset
of zero in the following situations as per ARMv8 specifications:
1) HCR_EL2.E2H is 1, and CNTVCT_EL0/CNTVCT are read from EL2.
2) HCR_EL2.{E2H, TGE} is {1, 1}, and either:
— CNTVCT_EL0 is read from Non-secure EL0 or EL2.
— CNTVCT is read from Non-secure EL0.
So, no need to zero CNTVOFF_EL2/CNTVOFF for VHE case.
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Acked-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
---
virt/kvm/arm/arch_timer.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 70268c0bec79..86eca32474cc 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -541,9 +541,11 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
* The kernel may decide to run userspace after calling vcpu_put, so
* we reset cntvoff to 0 to ensure a consistent read between user
* accesses to the virtual counter and kernel access to the physical
- * counter.
+ * counter of non-VHE case. For VHE, the virtual counter uses a fixed
+ * virtual offset of zero, so no need to zero CNTVOFF_EL2 register.
*/
- set_cntvoff(0);
+ if (!has_vhe())
+ set_cntvoff(0);
}
/*
--
2.14.2
