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From:   "Luck, Tony" <tony.luck@intel.com>
To:     Sean Christopherson <seanjc@google.com>,
        "Chatre, Reinette" <reinette.chatre@intel.com>
CC:     Jarkko Sakkinen <jarkko@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 1/4] x86/sgx: Track phase and type of SGX EPC pages
Thread-Topic: [PATCH 1/4] x86/sgx: Track phase and type of SGX EPC pages
Thread-Index: AQHXdCUcDncuRnkx9Ue+ht5iNpTdPatDbnyA//+NavCAAH2fgIAAHc8A//+QpcA=
Date:   Wed, 14 Jul 2021 23:39:01 +0000
Message-ID: <c0fa2e9e65da4f58893386279ce914c1@intel.com>
References: <20210708181423.1312359-1-tony.luck@intel.com>
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> I've no objection to tracking the type for SGX2, my argument in the context of
> #MC support is that there should be no need to track the type.  Either the #MC
> is recoverable or it isn't, and the enclave is toast regardless of what type of
> page hit the #MC.

I'll separate the "phase" from the "type".

Here phase is used for the life-cycle of EPC pages:

DIRTY -> FREE -> IN-USE -> DIRTY

Errors can be reported by memory controller page scrubbers
for pages that are not "IN-USE" ... and the recovery action is
just to make sure that they are never allocated.

When a page is IN-USE ... it has a "type". I currently
only have a way to inject errors into SGX_PAGE_TYPE_REG
pages. That means initial recovery code is going to focus on
those since that is all I can test. But I'll try not to special case
them as far as possible.

-Tony