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Message-ID: <80083e5ca3fd0a5bd2de43ebc803fc914d09ac3c.camel@kernel.org>
Subject: Re: [PATCH] x86/sgx: Add poison handling to reclaimer
From:   Jarkko Sakkinen <jarkko@kernel.org>
To:     Reinette Chatre <reinette.chatre@intel.com>, tony.luck@intel.com,
        dave.hansen@linux.intel.com, tglx@linutronix.de, bp@alien8.de,
        luto@kernel.org, mingo@redhat.com, linux-sgx@vger.kernel.org,
        x86@kernel.org
Cc:     linux-kernel@vger.kernel.org
Date:   Thu, 20 Jan 2022 14:57:56 +0200
In-Reply-To: <ef74bd9548df61f77e802e7505affcfb5159c48c.1642545829.git.reinette.chatre@intel.com>
References: <ef74bd9548df61f77e802e7505affcfb5159c48c.1642545829.git.reinette.chatre@intel.com>
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On Tue, 2022-01-18 at 15:05 -0800, Reinette Chatre wrote:
> The machine check recovery handling in SGX added the changes
> listed below to the freeing of pages in sgx_free_epc_page().
> The SGX reclaimer contains an open coded version of
> sgx_free_epc_page() and thus did not obtain the changes in
> support of poison handling.
>=20
> The changes made to EPC page freeing in support of poison handling
> are:
> 1) A new SGX_EPC_PAGE_IS_FREE flag is set when the EPC page is
> =C2=A0=C2=A0 freed. Introduced in commit d6d261bded8a ("x86/sgx: Add new
> =C2=A0=C2=A0 sgx_epc_page flag bit to mark free pages").
> 2) A new "poison" field in struct sgx_epc_page is used to
> =C2=A0=C2=A0 determine whether a newly freed EPC page should be placed
> =C2=A0=C2=A0 on the list of poisoned or list of free pages. Introduced
> =C2=A0=C2=A0 in commit 992801ae9243 ("x86/sgx: Initial poison handling
> =C2=A0=C2=A0 for dirty and free pages").
> 3) The owner field in struct sgx_epc_page is cleared when the EPC
> =C2=A0=C2=A0 page is freed.=C2=A0 Introduced in commit 992801ae9243 ("x86=
/sgx:
> =C2=A0=C2=A0 Initial poison handling for dirty and free pages").
>=20
> Replace the open coded enclave page freeing code in the reclaimer
> with sgx_free_epc_page() to obtain support for poison page handling.
>=20
> Fixes: d6d261bded8a ("x86/sgx: Add new sgx_epc_page flag bit to mark
> free pages")

AFAIK, this patch does not semantically break anything so it is not
a legit fixes tag.

BR, Jarkko