[PATCH] Revert "EDAC/mce_amd: Do not load edac_mce_amd module on guests"

[Elliott Mitchell <ehem+xen@xxxxxxx>]

This reverts commit 767f4b620edadac579c9b8b6660761d4285fa6f9.

There are at least 3 valid reasons why a VM may see MCE events/registers.

First, the hypervisor may have a bug.  Ideally this should be dealt with
by fixing the hypervisor.  Failing that, the hypervisor and versions
effected need to be identified so only they are flagged as buggy.

Second, the Linux kernel may be handling adminstrative duties/hardware
for a hypervisor.  In this case, the events need to be processed and
potentially passed back through the hypervisor.

Third, the hypervisor may do full virtualization of MCE events.  In such
case, they should be handled normally.

Any of these blanket disabling the functionality is bad.  The original
patch was wrong.
---
 drivers/edac/mce_amd.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/edac/mce_amd.c b/drivers/edac/mce_amd.c
index 9215c06783df..1b7fccfbb654 100644
--- a/drivers/edac/mce_amd.c
+++ b/drivers/edac/mce_amd.c
@@ -1361,9 +1361,6 @@ static int __init mce_amd_init(void)
            c->x86_vendor != X86_VENDOR_HYGON)
                return -ENODEV;
 
-       if (cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
-               return -ENODEV;
-
        if (boot_cpu_has(X86_FEATURE_SMCA)) {
                xec_mask = 0x3f;
                goto out;
-- 
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