linux/arch
Paolo Bonzini b8e8c8303f kvm: mmu: ITLB_MULTIHIT mitigation
With some Intel processors, putting the same virtual address in the TLB
as both a 4 KiB and 2 MiB page can confuse the instruction fetch unit
and cause the processor to issue a machine check resulting in a CPU lockup.

Unfortunately when EPT page tables use huge pages, it is possible for a
malicious guest to cause this situation.

Add a knob to mark huge pages as non-executable. When the nx_huge_pages
parameter is enabled (and we are using EPT), all huge pages are marked as
NX. If the guest attempts to execute in one of those pages, the page is
broken down into 4K pages, which are then marked executable.

This is not an issue for shadow paging (except nested EPT), because then
the host is in control of TLB flushes and the problematic situation cannot
happen.  With nested EPT, again the nested guest can cause problems shadow
and direct EPT is treated in the same way.

[ tglx: Fixup default to auto and massage wording a bit ]

Originally-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2019-11-04 12:22:02 +01:00
..
alpha mm: introduce MADV_PAGEOUT 2019-09-25 17:51:41 -07:00
arc ARC: perf: Accommodate big-endian CPU 2019-10-22 09:59:43 -07:00
arm ARM: SoC fixes 2019-10-25 16:00:47 -04:00
arm64 arm64 fixes for -rc6 2019-11-01 10:03:46 -07:00
c6x mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
csky csky-for-linus-5.4-rc1: arch/csky patches for 5.4-rc1 2019-09-30 10:16:17 -07:00
h8300 mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
hexagon mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
ia64 Merge branch 'akpm' (patches from Andrew) 2019-09-24 16:10:23 -07:00
m68k mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
microblaze Merge branch 'akpm' (patches from Andrew) 2019-09-24 16:10:23 -07:00
mips MIPS: tlbex: Fix build_restore_pagemask KScratch restore 2019-10-23 21:12:49 -07:00
nds32 mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
nios2 nios2 update for v5.4-rc1 2019-09-27 13:02:19 -07:00
openrisc mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
parisc parisc: fix frame pointer in ftrace_regs_caller() 2019-10-30 21:24:40 +01:00
powerpc powerpc fixes for 5.4 #4 2019-11-02 11:08:19 -07:00
riscv RISC-V: Add PCIe I/O BAR memory mapping 2019-10-28 10:43:32 -07:00
s390 s390/idle: fix cpu idle time calculation 2019-10-31 17:26:48 +01:00
sh mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
sparc sparc64: disable fast-GUP due to unexplained oopses 2019-10-15 09:56:36 -07:00
um um-ubd: Entrust re-queue to the upper layers 2019-10-29 10:07:41 -06:00
unicore32 mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
x86 kvm: mmu: ITLB_MULTIHIT mitigation 2019-11-04 12:22:02 +01:00
xtensa xtensa: fix change_bit in exclusive access option 2019-10-16 00:14:33 -07:00
.gitignore
Kconfig arm64, mm: make randomization selected by generic topdown mmap layout 2019-09-24 15:54:11 -07:00