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Date:   Tue, 15 Jun 2021 09:45:25 -0700
From:   "Luck, Tony" <tony.luck@intel.com>
To:     Yazen Ghannam <yazen.ghannam@amd.com>
Cc:     Borislav Petkov <bp@alien8.de>,
        Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        James Morse <james.morse@arm.com>,
        Robert Richter <rric@kernel.org>
Subject: Re: [PATCH] EDAC/Intel: Do not load EDAC driver when running as a
 guest
Message-ID: <20210615164525.GA1087213@agluck-desk2.amr.corp.intel.com>
References: <20210614212129.227698-1-Smita.KoralahalliChannabasappa@amd.com>
 <YMfRxX/M4rJ5gM/R@zn.tnic>
 <16a34b6834f94f139444c2ff172645e9@intel.com>
 <YMhwAZaFr4d1QOGG@zn.tnic>
 <20210615150846.GA409@aus-x-yghannam.amd.com>
 <YMjE2iwRFWVrfzLL@zn.tnic>
 <20210615160009.GA29258@aus-x-yghannam.amd.com>
 <YMjRGFiqp2HNWUrZ@zn.tnic>
 <20210615163221.GA2991@aus-x-yghannam.amd.com>
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In-Reply-To: <20210615163221.GA2991@aus-x-yghannam.amd.com>
Precedence: bulk

There's little to no point in loading an EDAC driver running in a guest:
1) The CPU model reported by CPUID may not represent actual h/w
2) The hypervisor likely does not pass in access to memory controller devices
3) Hypervisors generally do not pass corrected error details to guests

Add a check in each of the Intel EDAC drivers for X86_FEATURE_HYPERVISOR
and simply return -ENODEV in the init routine.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 drivers/edac/i10nm_base.c | 3 +++
 drivers/edac/pnd2_edac.c  | 3 +++
 drivers/edac/sb_edac.c    | 3 +++
 drivers/edac/skx_base.c   | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/drivers/edac/i10nm_base.c b/drivers/edac/i10nm_base.c
index 238a4ad1e526..fa08622ff2a8 100644
--- a/drivers/edac/i10nm_base.c
+++ b/drivers/edac/i10nm_base.c
@@ -278,6 +278,9 @@ static int __init i10nm_init(void)
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
 
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return -ENODEV;
+
 	id = x86_match_cpu(i10nm_cpuids);
 	if (!id)
 		return -ENODEV;
diff --git a/drivers/edac/pnd2_edac.c b/drivers/edac/pnd2_edac.c
index 928f63a374c7..5c7b36e2325f 100644
--- a/drivers/edac/pnd2_edac.c
+++ b/drivers/edac/pnd2_edac.c
@@ -1554,6 +1554,9 @@ static int __init pnd2_init(void)
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
 
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return -ENODEV;
+
 	id = x86_match_cpu(pnd2_cpuids);
 	if (!id)
 		return -ENODEV;
diff --git a/drivers/edac/sb_edac.c b/drivers/edac/sb_edac.c
index 93daa4297f2e..7d3b2b164e3c 100644
--- a/drivers/edac/sb_edac.c
+++ b/drivers/edac/sb_edac.c
@@ -3510,6 +3510,9 @@ static int __init sbridge_init(void)
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
 
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return -ENODEV;
+
 	id = x86_match_cpu(sbridge_cpuids);
 	if (!id)
 		return -ENODEV;
diff --git a/drivers/edac/skx_base.c b/drivers/edac/skx_base.c
index 6a4f0b27c654..c2f9da941217 100644
--- a/drivers/edac/skx_base.c
+++ b/drivers/edac/skx_base.c
@@ -656,6 +656,9 @@ static int __init skx_init(void)
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
 
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return -ENODEV;
+
 	id = x86_match_cpu(skx_cpuids);
 	if (!id)
 		return -ENODEV;
-- 
2.29.2