linux-stable/arch/x86/mm
Kirill A. Shutemov b82a8dbd3d x86/coco: Disable 32-bit emulation by default on TDX and SEV
The INT 0x80 instruction is used for 32-bit x86 Linux syscalls. The
kernel expects to receive a software interrupt as a result of the INT
0x80 instruction. However, an external interrupt on the same vector
triggers the same handler.

The kernel interprets an external interrupt on vector 0x80 as a 32-bit
system call that came from userspace.

A VMM can inject external interrupts on any arbitrary vector at any
time.  This remains true even for TDX and SEV guests where the VMM is
untrusted.

Put together, this allows an untrusted VMM to trigger int80 syscall
handling at any given point. The content of the guest register file at
that moment defines what syscall is triggered and its arguments. It
opens the guest OS to manipulation from the VMM side.

Disable 32-bit emulation by default for TDX and SEV. User can override
it with the ia32_emulation=y command line option.

[ dhansen: reword the changelog ]

Reported-by: Supraja Sridhara <supraja.sridhara@inf.ethz.ch>
Reported-by: Benedict Schlüter <benedict.schlueter@inf.ethz.ch>
Reported-by: Mark Kuhne <mark.kuhne@inf.ethz.ch>
Reported-by: Andrin Bertschi <andrin.bertschi@inf.ethz.ch>
Reported-by: Shweta Shinde <shweta.shinde@inf.ethz.ch>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@vger.kernel.org> # v6.0+: 1da5c9b x86: Introduce ia32_enabled()
Cc: <stable@vger.kernel.org> # v6.0+
2023-12-07 09:51:10 -08:00
..
pat x86/mm: Remove _PAGE_DIRTY from kernel RO pages 2023-07-11 14:12:19 -07:00
amdtopology.c x86/mm: Replace nodes_weight() with nodes_empty() where appropriate 2022-04-10 22:35:38 +02:00
cpu_entry_area.c x86/mm: Do not shuffle CPU entry areas without KASLR 2023-03-22 10:42:47 -07:00
debug_pagetables.c x86/mm/dump_pagetables: remove MODULE_LICENSE in non-modules 2023-04-13 13:13:54 -07:00
dump_pagetables.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
extable.c x86-64: mm: clarify the 'positive addresses' user address rules 2023-05-03 10:37:22 -07:00
fault.c Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
highmem_32.c x86/mm: Include asm/numa.h for set_highmem_pages_init() 2023-05-18 11:56:18 -07:00
hugetlbpage.c arch/x86/mm/hugetlbpage.c: pud_huge() returns 0 when using 2-level paging 2022-11-08 15:57:25 -08:00
ident_map.c x86/mm/ident_map: Check for errors from ident_pud_init() 2020-10-28 14:48:30 +01:00
init.c - Remove unnecessary "INVPCID single" feature tracking 2023-08-30 09:54:00 -07:00
init_32.c x86/mm: Remove Xen-PV leftovers from init_32.c 2023-06-09 11:00:21 +02:00
init_64.c mm/sparse-vmemmap: generalise vmemmap_populate_hugepages() 2022-12-11 18:12:12 -08:00
iomap_32.c io-mapping: Cleanup atomic iomap 2020-11-06 23:14:58 +01:00
ioremap.c x86/ioremap: Add hypervisor callback for private MMIO mapping in coco VM 2023-03-26 23:42:40 +02:00
kasan_init_64.c x86/kasan: Populate shadow for shared chunk of the CPU entry area 2022-12-15 10:37:28 -08:00
kaslr.c x86/mm: Avoid using set_pgd() outside of real PGD pages 2023-06-16 11:46:42 -07:00
kmmio.c x86/mm/kmmio: Remove redundant preempt_disable() 2022-12-12 10:54:48 -05:00
kmsan_shadow.c x86: kmsan: handle CPU entry area 2022-10-03 14:03:26 -07:00
maccess.c x86/sev-es: Allow copy_from_kernel_nofault() in earlier boot 2023-09-28 22:49:35 +02:00
Makefile x86: kmsan: handle CPU entry area 2022-10-03 14:03:26 -07:00
mem_encrypt.c x86/sev: Move sev_setup_arch() to mem_encrypt.c 2023-10-11 10:15:47 +02:00
mem_encrypt_amd.c x86/coco: Disable 32-bit emulation by default on TDX and SEV 2023-12-07 09:51:10 -08:00
mem_encrypt_boot.S x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros 2022-12-15 10:37:27 -08:00
mem_encrypt_identity.c - Yosry Ahmed brought back some cgroup v1 stats in OOM logs. 2023-06-28 10:28:11 -07:00
mm_internal.h x86/mm: thread pgprot_t through init_memory_mapping() 2020-04-10 15:36:21 -07:00
mmap.c x86/mm/mmap: Fix -Wmissing-prototypes warnings 2020-04-22 20:19:48 +02:00
mmio-mod.c x86: Replace cpumask_weight() with cpumask_empty() where appropriate 2022-04-10 22:35:38 +02:00
numa.c X86 core code updates: 2023-10-30 17:37:47 -10:00
numa_32.c x86/mm: Drop deprecated DISCONTIGMEM support for 32-bit 2020-05-28 18:34:30 +02:00
numa_64.c
numa_emulation.c x86/mm: Replace nodes_weight() with nodes_empty() where appropriate 2022-04-10 22:35:38 +02:00
numa_internal.h
pf_in.c
pf_in.h
pgprot.c x86/mm: move protection_map[] inside the platform 2022-07-17 17:14:38 -07:00
pgtable.c mm: add statistics for PUD level pagetable 2023-10-06 14:44:10 -07:00
pgtable_32.c mm: remove unneeded includes of <asm/pgalloc.h> 2020-08-07 11:33:26 -07:00
physaddr.c
physaddr.h
pkeys.c x86/pkeys: Clarify PKRU_AD_KEY macro 2022-06-07 16:06:33 -07:00
pti.c x86/pti: Fix kernel warnings for pti= and nopti cmdline options 2023-10-20 12:50:14 +02:00
srat.c x86/apic: Wrap APIC ID validation into an inline 2023-08-09 11:58:30 -07:00
testmmiotrace.c
tlb.c - Remove unnecessary "INVPCID single" feature tracking 2023-08-30 09:54:00 -07:00