linux-kernel - Re: [PATCH 0/3] recover hardware corrupted page by virtio balloon

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Date:   Wed, 25 May 2022 13:16:34 -0700
From:   Jue Wang <juew@...gle.com>
To:     pizhenwei@...edance.com
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>, jasowang@...hat.com,
        LKML <linux-kernel@...r.kernel.org>,
        Linux MM <linux-mm@...ck.org>, mst@...hat.com,
        HORIGUCHI NAOYA(堀口 直也) 
        <naoya.horiguchi@....com>, Paolo Bonzini <pbonzini@...hat.com>,
        Peter Xu <peterx@...hat.com>, qemu-devel@...gnu.org,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH 0/3] recover hardware corrupted page by virtio balloon

Some points to consider:

The injected MCE has _done_ the damages to guest workload. Recovering
the guest poisoned memory doesn't help with the already happened guest
workload memory corruption / loss / interruption due to injected MCEs.

The hypervisor _must_ emulate poisons identified in guest physical
address space (could be transported from the source VM), this is to
prevent silent data corruption in the guest. With a paravirtual
approach like this patch series, the hypervisor can clear some of the
poisoned HVAs knowing for certain that the guest OS has isolated the
poisoned page. I wonder how much value it provides to the guest if the
guest and workload are _not_ in a pressing need for the extra KB/MB
worth of memory.

Thanks,
-Jue