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author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2022-06-14 15:01:35 +0300 |
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committer | Dave Hansen <dave.hansen@linux.intel.com> | 2022-06-17 15:37:33 -0700 |
commit | 1e7769653b06b56b7ea7d56911d2d5b2957750cd (patch) | |
tree | 25a3810999acb293a056132330d6c3b872fb850b /drivers/peci | |
parent | cdd85786f4b3b9273e4376e69aa95a2d71722764 (diff) | |
download | linux-1e7769653b06b56b7ea7d56911d2d5b2957750cd.tar.bz2 |
x86/tdx: Handle load_unaligned_zeropad() page-cross to a shared page
load_unaligned_zeropad() can lead to unwanted loads across page boundaries.
The unwanted loads are typically harmless. But, they might be made to
totally unrelated or even unmapped memory. load_unaligned_zeropad()
relies on exception fixup (#PF, #GP and now #VE) to recover from these
unwanted loads.
In TDX guests, the second page can be shared page and a VMM may configure
it to trigger #VE.
The kernel assumes that #VE on a shared page is an MMIO access and tries to
decode instruction to handle it. In case of load_unaligned_zeropad() it
may result in confusion as it is not MMIO access.
Fix it by detecting split page MMIO accesses and failing them.
load_unaligned_zeropad() will recover using exception fixups.
The issue was discovered by analysis and reproduced artificially. It was
not triggered during testing.
[ dhansen: fix up changelogs and comments for grammar and clarity,
plus incorporate Kirill's off-by-one fix]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220614120135.14812-4-kirill.shutemov@linux.intel.com
Diffstat (limited to 'drivers/peci')
0 files changed, 0 insertions, 0 deletions