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linux-stable/arch/x86/lib
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Joerg Roedel 4009a4ac82 x86/sev: Unroll string mmio with CC_ATTR_GUEST_UNROLL_STRING_IO 
The io-specific memcpy/memset functions use string mmio accesses to do
their work. Under SEV, the hypervisor can't emulate these instructions
because they read/write directly from/to encrypted memory.

KVM will inject a page fault exception into the guest when it is asked
to emulate string mmio instructions for an SEV guest:

  BUG: unable to handle page fault for address: ffffc90000065068
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 8000100000067 P4D 8000100000067 PUD 80001000fb067 PMD 80001000fc067 PTE 80000000fed40173
  Oops: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc7 #3

As string mmio for an SEV guest can not be supported by the
hypervisor, unroll the instructions for CC_ATTR_GUEST_UNROLL_STRING_IO
enabled kernels.

This issue appears when kernels are launched in recent libvirt-managed
SEV virtual machines, because virt-install started to add a tpm-crb
device to the guest by default and proactively because, raisins:

  eb58c09f48

and as that commit says, the default adding of a TPM can be disabled
with "virt-install ... --tpm none".

The kernel driver for tpm-crb uses memcpy_to/from_io() functions to
access MMIO memory, resulting in a page-fault injected by KVM and
crashing the kernel at boot.

  [ bp: Massage and extend commit message. ]

Fixes: d8aa7eea78 ('x86/mm: Add Secure Encrypted Virtualization (SEV) support')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220321093351.23976-1-joro@8bytes.org
2022-03-29 15:59:16 +02:00
..
.gitignore
atomic64_32.c
atomic64_386_32.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
atomic64_cx8_32.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
cache-smp.c
checksum_32.S x86/checksum_32: Remove .fixup usage 2021-12-11 09:09:49 +01:00
clear_page_64.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
cmdline.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
cmpxchg8b_emu.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
cmpxchg16b_emu.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
copy_mc.c x86, libnvdimm/test: Remove COPY_MC_TEST 2020-10-26 18:08:35 +01:00
copy_mc_64.S x86/copy_mc_64: Remove .fixup usage 2021-12-11 09:09:46 +01:00
copy_page_64.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
copy_user_64.S - Get rid of all the .fixup sections because this generates 2022-01-12 16:31:19 -08:00
cpu.c
csum-copy_64.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
csum-partial_64.c x86/csum: Rewrite/optimize csum_partial() 2021-12-08 11:26:09 +01:00
csum-wrappers_64.c amd64: switch csum_partial_copy_generic() to new calling conventions 2020-08-20 15:45:22 -04:00
delay.c
error-inject.c x86: Prepare inline-asm for straight-line-speculation 2021-12-08 19:23:12 +01:00
getuser.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
hweight.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
inat.c x86/insn: Add a __ignore_sync_check__ marker 2021-03-15 11:00:57 +01:00
insn-eval.c - Get rid of all the .fixup sections because this generates 2022-01-12 16:31:19 -08:00
insn.c x86/insn: Use get_unaligned() instead of memcpy() 2021-10-06 11:56:37 +02:00
iomap_copy_64.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
iomem.c x86/sev: Unroll string mmio with CC_ATTR_GUEST_UNROLL_STRING_IO 2022-03-29 15:59:16 +02:00
kaslr.c x86/boot: Allow a "silent" kaslr random byte fetch 2021-10-27 11:07:58 +02:00
Makefile x86/mmx_32: Remove X86_USE_3DNOW 2021-12-11 09:09:45 +01:00
memcpy_32.c x86/mmx_32: Remove X86_USE_3DNOW 2021-12-11 09:09:45 +01:00
memcpy_64.S x86: clean up symbol aliasing 2022-02-22 16:21:34 +00:00
memmove_64.S x86: clean up symbol aliasing 2022-02-22 16:21:34 +00:00
memset_64.S x86: clean up symbol aliasing 2022-02-22 16:21:34 +00:00
misc.c
mmx_32.c x86/mmx_32: Remove X86_USE_3DNOW 2021-12-11 09:09:45 +01:00
msr-reg-export.c
msr-reg.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
msr-smp.c x86/msr: Fix wr/rdmsr_safe_regs_on_cpu() prototypes 2021-03-22 21:37:03 +01:00
msr.c x86/msr: Make locally used functions static 2021-04-08 11:57:40 +02:00
pc-conf-reg.c x86: Add support for 0x22/0x23 port I/O configuration space 2021-08-10 23:31:43 +02:00
putuser.S x86: Prepare asm files for straight-line-speculation 2021-12-08 12:25:37 +01:00
retpoline.S x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE 2022-02-21 10:21:28 +01:00
string_32.c lib/string: Move helper functions out of string.c 2021-09-25 08:20:49 -07:00
strstr_32.c
usercopy.c x86/uaccess: Document copy_from_user_nmi() 2020-11-18 13:19:01 +01:00
usercopy_32.c x86/usercopy: Remove .fixup usage 2021-12-11 09:09:50 +01:00
usercopy_64.c x86/usercopy: Remove .fixup usage 2021-12-11 09:09:50 +01:00
x86-opcode-map.txt x86/insn: Add AVX512-FP16 instructions to the x86 instruction decoder 2022-01-23 20:38:01 +01:00