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From:   Peter Maydell <peter.maydell@linaro.org>
Date:   Mon, 13 May 2019 10:44:05 +0100
Message-ID: <CAFEAcA-S6Kh8yUqVZVA8gtDdRscgVaTfC4CwxngoS2ZPt6K9ww@mail.gmail.com>
Subject: Re: [RFC PATCH V2] kvm: arm64: export memory error recovery
 capability to user space
To:     Dongjiu Geng <gengdongjiu@huawei.com>
Cc:     Christoffer Dall <christoffer.dall@arm.com>,
        Marc Zyngier <marc.zyngier@arm.com>,
        James Morse <james.morse@arm.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        kvm-devel <kvm@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
        arm-mail-list <linux-arm-kernel@lists.infradead.org>,
        kvmarm@lists.cs.columbia.edu, Zheng Xiang <zhengxiang9@huawei.com>
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On Mon, 13 May 2019 at 07:32, Dongjiu Geng <gengdongjiu@huawei.com> wrote:
>
> When user space do memory recovery, it will check whether KVM and
> guest support the error recovery, only when both of them support,
> user space will do the error recovery. This patch exports this
> capability of KVM to user space.
>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
> ---
> v1->v2:
> 1. check whether host support memory failure instead of RAS capability
>    https://patchwork.kernel.org/patch/10730827/
>
> v1:
> 1. User space needs to check this capability of host is suggested by Peter[1],
> this patch as RFC tag because user space patches are still under review,
> so this kernel patch is firstly sent out for review.
>
> [1]: https://patchwork.codeaurora.org/patch/652261/
> ---

I thought the conclusion of the thread on the v1 patch was that
userspace doesn't need to specifically ask the host kernel if
it has support for this -- if it does not, then the host kernel
will just never deliver userspace any SIGBUS with MCEERR code,
which is fine. Or am I still confused?

thanks
-- PMM