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| author | Shanker Donthineni <shankerd@codeaurora.org> | 2018-02-19 09:38:07 -0600 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@linaro.org> | 2018-02-26 10:48:02 +0100 |
| commit | 250be9d61cf8898b1eea140fa31fe7713c49e989 (patch) | |
| tree | 2c0988d8b3d131ddae9c0ef6a20e78310bbe729f | |
| parent | b9fb17395b956079e2c3961a310f6a961a7de6e6 (diff) | |
| download | linux-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.c | 6 |
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); } /* |