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authorShanker Donthineni <shankerd@codeaurora.org>2018-02-19 09:38:07 -0600
committerChristoffer Dall <christoffer.dall@linaro.org>2018-02-26 10:48:02 +0100
commit250be9d61cf8898b1eea140fa31fe7713c49e989 (patch)
tree2c0988d8b3d131ddae9c0ef6a20e78310bbe729f
parentb9fb17395b956079e2c3961a310f6a961a7de6e6 (diff)
downloadlinux-250be9d61cf8898b1eea140fa31fe7713c49e989.tar.bz2
KVM: arm/arm64: No need to zero CNTVOFF in kvm_timer_vcpu_put() for VHE
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@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
-rw-r--r--virt/kvm/arm/arch_timer.c6
1 files 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);
}
/*