Messages in this thread | | | From | Peter Maydell <> | Date | Fri, 8 Sep 2017 15:55:53 +0100 | Subject | Re: [PATCH v11 4/6] target-arm: kvm64: detect guest RAS EXTENSION feature |
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On 8 September 2017 at 15:26, gengdongjiu <gengdongjiu@huawei.com> wrote:
>> Shouldn't we need to also tell the kernel that we actually want >> it to expose RAS to the guest? Compare the PMU code in this function, >> where we set a kvm_init_features bit to do this.
> In the PMU code, it indeed sets a kvm_init_features bit. Here ARM > James has a concern that we are depend on the host CPU RAS extension, > He means that if userspace receives the SIGBUS delivered by host > memory_failure(), user space should record the CPER for guest > and handling the error regardless whether host CPU supports RAS > extension. But I think if user space receives the SIGBUS signal, > that means > host CPU RAS module detects the error or CPU consumes the poison > data, thus we should check whether physical CPU support RAS extension.
I don't understand what you have in mind here. If the host does not support the CPU RAS extension then we should never get a SIGBUS in the first place.
In any case this doesn't seem relevant to the question of whether it should be optional to expose the RAS extension to the *guest*. Even if the host does support RAS, you should be able to run a VM that knows nothing about RAS.
thanks -- PMM
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