Commit f9f57da2 authored by Juergen Gross's avatar Juergen Gross Committed by Borislav Petkov (AMD)

x86/mtrr: Revert 90b926e6 ("x86/pat: Fix pat_x_mtrr_type() for MTRR disabled case")

Commit

  90b926e6 ("x86/pat: Fix pat_x_mtrr_type() for MTRR disabled case")

broke the use case of running Xen dom0 kernels on machines with an
external disk enclosure attached via USB, see Link tag.

What this commit was originally fixing - SEV-SNP guests on Hyper-V - is
a more specialized situation which has other issues at the moment anyway
so reverting this now and addressing the issue properly later is the
prudent thing to do.

So revert it in time for the 6.2 proper release.

  [ bp: Rewrite commit message. ]
Reported-by: default avatarChristian Kujau <lists@nerdbynature.de>
Tested-by: default avatarChristian Kujau <lists@nerdbynature.de>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/4fe9541e-4d4c-2b2a-f8c8-2d34a7284930@nerdbynature.de
parent ceaa837f
...@@ -387,8 +387,7 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end, ...@@ -387,8 +387,7 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end,
u8 mtrr_type, uniform; u8 mtrr_type, uniform;
mtrr_type = mtrr_type_lookup(start, end, &uniform); mtrr_type = mtrr_type_lookup(start, end, &uniform);
if (mtrr_type != MTRR_TYPE_WRBACK && if (mtrr_type != MTRR_TYPE_WRBACK)
mtrr_type != MTRR_TYPE_INVALID)
return _PAGE_CACHE_MODE_UC_MINUS; return _PAGE_CACHE_MODE_UC_MINUS;
return _PAGE_CACHE_MODE_WB; return _PAGE_CACHE_MODE_WB;
......
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