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A long time ago it was agreed upon that the coco stuff needs to go where
it belongs:
https://lore.kernel.org/all/Yg5nh1RknPRwIrb8@zn.tnic
and not keep it in arch/x86/kernel. TDX did that and SEV can't find time
to do so. So lemme do it. If people have trouble converting their
ongoing featuritis patches, ask me for a sed script.
No functional changes.
Move the instrumentation exclusion bits too, as helpfully caught and
reported by the 0day folks.
Closes: https://lore.kernel.org/oe-kbuild-all/202406220748.hG3qlmDx-lkp@intel.com
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202407091342.46d7dbb-oliver.sang@intel.com
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Reviewed-by: Ashish Kalra <ashish.kalra@amd.com>
Tested-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/r/20240619093014.17962-1-bp@kernel.org
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To allow execution at a level other than VMPL0, an SVSM must be present.
Allow the SEV-SNP guest to continue booting if an SVSM is detected and
the hypervisor supports the SVSM feature as indicated in the GHCB
hypervisor features bitmap.
[ bp: Massage a bit. ]
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/2ce7cf281cce1d0cba88f3f576687ef75dc3c953.1717600736.git.thomas.lendacky@amd.com
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The PVALIDATE instruction can only be performed at VMPL0. If an SVSM is
present, it will be running at VMPL0 while the guest itself is then
running at VMPL1 or a lower privilege level.
In that case, use the SVSM_CORE_PVALIDATE call to perform memory
validation instead of issuing the PVALIDATE instruction directly.
The validation of a single 4K page is now explicitly identified as such
in the function name, pvalidate_4k_page(). The pvalidate_pages()
function is used for validating 1 or more pages at either 4K or 2M in
size. Each function, however, determines whether it can issue the
PVALIDATE directly or whether the SVSM needs to be invoked.
[ bp: Touchups. ]
[ Tom: fold in a fix for Coconut SVSM:
https://lore.kernel.org/r/234bb23c-d295-76e5-a690-7ea68dc1118b@amd.com ]
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/4c4017d8b94512d565de9ccb555b1a9f8983c69c.1717600736.git.thomas.lendacky@amd.com
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During early boot phases, check for the presence of an SVSM when running
as an SEV-SNP guest.
An SVSM is present if not running at VMPL0 and the 64-bit value at offset
0x148 into the secrets page is non-zero. If an SVSM is present, save the
SVSM Calling Area address (CAA), located at offset 0x150 into the secrets
page, and set the VMPL level of the guest, which should be non-zero, to
indicate the presence of an SVSM.
[ bp: Touchups. ]
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/9d3fe161be93d4ea60f43c2a3f2c311fe708b63b.1717600736.git.thomas.lendacky@amd.com
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Currently, the enforce_vmpl0() function uses a set argument when modifying
the VMPL1 permissions used to test for VMPL0. If the guest is not running
at VMPL0, the guest self-terminates.
The function is just a wrapper for a fixed RMPADJUST function. Eliminate
the function and perform the RMPADJUST directly.
No functional change.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/ed01ddf04bfb475596b24b634fd26cffaa85173a.1713974291.git.thomas.lendacky@amd.com
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The snp_init() function in boot/compressed/sev.c is local to that file, is
not called from outside of the file and is independent of the snp_init()
function in kernel/sev.c. Change the name to better differentiate when
each function is used.
Move the renamed snp_init() and related functions up in the file to avoid
having to add a forward declaration and make the function static.
No functional change.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/afda29585c2724b9698003f24cefa77eb35f4ffb.1713974291.git.thomas.lendacky@amd.com
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There's a new conflict with Linus's upstream tree, because
in the following merge conflict resolution in <asm/coco.h>:
38b334fc767e Merge tag 'x86_sev_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Linus has resolved the conflicting placement of 'cc_mask' better
than the original commit:
1c811d403afd x86/sev: Fix position dependent variable references in startup code
... which was also done by an internal merge resolution:
2e5fc4786b7a Merge branch 'x86/sev' into x86/boot, to resolve conflicts and to pick up dependent tree
But Linus is right in 38b334fc767e, the 'cc_mask' declaration is sufficient
within the #ifdef CONFIG_ARCH_HAS_CC_PLATFORM block.
So instead of forcing Linus to do the same resolution again, merge in Linus's
tree and follow his conflict resolution.
Conflicts:
arch/x86/include/asm/coco.h
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 build updates from Ingo Molnar:
- Reduce <asm/bootparam.h> dependencies
- Simplify <asm/efi.h>
- Unify *_setup_data definitions into <asm/setup_data.h>
- Reduce the size of <asm/bootparam.h>
* tag 'x86-build-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Do not include <asm/bootparam.h> in several files
x86/efi: Implement arch_ima_efi_boot_mode() in source file
x86/setup: Move internal setup_data structures into setup_data.h
x86/setup: Move UAPI setup structures into setup_data.h
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In preparation for implementing rigorous build time checks to enforce
that only code that can support it will be called from the early 1:1
mapping of memory, move SEV init code that is called in this manner to
the .head.text section.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240227151907.387873-19-ardb+git@google.com
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It is, and will be even more useful in the future, to dump the SEV
features enabled according to SEV_STATUS. Do so:
[ 0.542753] Memory Encryption Features active: AMD SEV SEV-ES SEV-SNP
[ 0.544425] SEV: Status: SEV SEV-ES SEV-SNP DebugSwap
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://lore.kernel.org/r/20240219094216.GAZdMieDHKiI8aaP3n@fat_crate.local
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Remove the include statement for <asm/bootparam.h> from several files
that don't require it and limit the exposure of those definitions within
the Linux kernel code.
[ bp: Massage commit message. ]
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240112095000.8952-5-tzimmermann@suse.de
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Compare the opcode bytes at rIP for each #VC exit reason to verify the
instruction which raised the #VC exception is actually the right one.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240105101407.11694-1-bp@alien8.de
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm handling updates from Ingo Molnar:
- Add new NX-stack self-test
- Improve NUMA partial-CFMWS handling
- Fix #VC handler bugs resulting in SEV-SNP boot failures
- Drop the 4MB memory size restriction on minimal NUMA nodes
- Reorganize headers a bit, in preparation to header dependency
reduction efforts
- Misc cleanups & fixes
* tag 'x86-mm-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Drop the 4 MB restriction on minimal NUMA node memory size
selftests/x86/lam: Zero out buffer for readlink()
x86/sev: Drop unneeded #include
x86/sev: Move sev_setup_arch() to mem_encrypt.c
x86/tdx: Replace deprecated strncpy() with strtomem_pad()
selftests/x86/mm: Add new test that userspace stack is in fact NX
x86/sev: Make boot_ghcb_page[] static
x86/boot: Move x86_cache_alignment initialization to correct spot
x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach
x86/sev-es: Allow copy_from_kernel_nofault() in earlier boot
x86_64: Show CR4.PSE on auxiliaries like on BSP
x86/iommu/docs: Update AMD IOMMU specification document URL
x86/sev/docs: Update document URL in amd-memory-encryption.rst
x86/mm: Move arch_memory_failure() and arch_is_platform_page() definitions from <asm/processor.h> to <asm/pgtable.h>
ACPI/NUMA: Apply SRAT proximity domain to entire CFMWS window
x86/numa: Introduce numa_fill_memblks()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:
- Rework PE header generation, primarily to generate a modern, 4k
aligned kernel image view with narrower W^X permissions.
- Further refine init-lifetime annotations
- Misc cleanups & fixes
* tag 'x86-boot-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86/boot: efistub: Assign global boot_params variable
x86/boot: Rename conflicting 'boot_params' pointer to 'boot_params_ptr'
x86/head/64: Move the __head definition to <asm/init.h>
x86/head/64: Add missing __head annotation to startup_64_load_idt()
x86/head/64: Mark 'startup_gdt[]' and 'startup_gdt_descr' as __initdata
x86/boot: Harmonize the style of array-type parameter for fixup_pointer() calls
x86/boot: Fix incorrect startup_gdt_descr.size
x86/boot: Compile boot code with -std=gnu11 too
x86/boot: Increase section and file alignment to 4k/512
x86/boot: Split off PE/COFF .data section
x86/boot: Drop PE/COFF .reloc section
x86/boot: Construct PE/COFF .text section from assembler
x86/boot: Derive file size from _edata symbol
x86/boot: Define setup size in linker script
x86/boot: Set EFI handover offset directly in header asm
x86/boot: Grab kernel_info offset from zoffset header directly
x86/boot: Drop references to startup_64
x86/boot: Drop redundant code setting the root device
x86/boot: Omit compression buffer from PE/COFF image memory footprint
x86/boot: Remove the 'bugger off' message
...
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The x86 decompressor is built and linked as a separate executable, but
it shares components with the kernel proper, which are either #include'd
as C files, or linked into the decompresor as a static library (e.g, the
EFI stub)
Both the kernel itself and the decompressor define a global symbol
'boot_params' to refer to the boot_params struct, but in the former
case, it refers to the struct directly, whereas in the decompressor, it
refers to a global pointer variable referring to the struct boot_params
passed by the bootloader or constructed from scratch.
This ambiguity is unfortunate, and makes it impossible to assign this
decompressor variable from the x86 EFI stub, given that declaring it as
extern results in a clash. So rename the decompressor version (whose
scope is limited) to boot_params_ptr.
[ mingo: Renamed 'boot_params_p' to 'boot_params_ptr' for clarity ]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
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Check the memory operand of INS/OUTS before emulating the instruction.
The #VC exception can get raised from user-space, but the memory operand
can be manipulated to access kernel memory before the emulation actually
begins and after the exception handler has run.
[ bp: Massage commit message. ]
Fixes: 597cfe48212a ("x86/boot/compressed/64: Setup a GHCB-based VC Exception handler")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
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Check the IO permission bitmap (if present) before emulating IOIO #VC
exceptions for user-space. These permissions are checked by hardware
already before the #VC is raised, but due to the VC-handler decoding
race it needs to be checked again in software.
Fixes: 25189d08e516 ("x86/sev-es: Add support for handling IOIO exceptions")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Dohrmann <erbse.13@gmx.de>
Cc: <stable@kernel.org>
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boot_ghcb_page is not used by any other file, so make it static.
This also resolves sparse warning:
arch/x86/boot/compressed/sev.c:28:13: warning: symbol 'boot_ghcb_page' was not declared. Should it be static?
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov:
- Handle the case where the beginning virtual address of the address
range whose SEV encryption status needs to change, is not page
aligned so that callers which round up the number of pages to be
decrypted, would mark a trailing page as decrypted and thus cause
corruption during live migration.
- Return an error from the #VC handler on AMD SEV-* guests when the
debug registers swapping is enabled as a DR7 access should not happen
then - that register is guest/host switched.
* tag 'x86_sev_for_v6.6_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev: Make enc_dec_hypercall() accept a size instead of npages
x86/sev: Do not handle #VC for DR7 read/write
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With MSR_AMD64_SEV_DEBUG_SWAP enabled, the guest is not expected to
receive a #VC for reads or writes of DR7.
Update the SNP_FEATURES_PRESENT mask with MSR_AMD64_SNP_DEBUG_SWAP so
an SNP guest doesn't gracefully terminate during SNP feature negotiation
if MSR_AMD64_SEV_DEBUG_SWAP is enabled.
Since a guest is not expected to receive a #VC on DR7 accesses when
MSR_AMD64_SEV_DEBUG_SWAP is enabled, return an error from the #VC
handler in this situation.
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Link: https://lore.kernel.org/r/20230816022122.981998-1-aik@amd.com
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Before refactoring the EFI stub boot flow to avoid the legacy bare metal
decompressor, duplicate the SNP feature check in the EFI stub before
handing over to the kernel proper.
The SNP feature check can be performed while running under the EFI boot
services, which means it can force the boot to fail gracefully and
return an error to the bootloader if the loaded kernel does not
implement support for all the features that the hypervisor enabled.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-23-ardb@kernel.org
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Tao Liu reported a boot hang on an Intel Atom machine due to an unmapped
EFI config table. The reason being that the CC blob which contains the
CPUID page for AMD SNP guests is parsed for before even checking
whether the machine runs on AMD hardware.
Usually that's not a problem on !AMD hw - it simply won't find the CC
blob's GUID and return. However, if any parts of the config table
pointers array is not mapped, the kernel will #PF very early in the
decompressor stage without any opportunity to recover.
Therefore, do a superficial CPUID check before poking for the CC blob.
This will fix the current issue on real hardware. It would also work as
a guest on a non-lying hypervisor.
For the lying hypervisor, the check is done again, *after* parsing the
CC blob as the real CPUID page will be present then.
Clear the #VC handler in case SEV-{ES,SNP} hasn't been detected, as
a precaution.
Fixes: c01fce9cef84 ("x86/compressed: Add SEV-SNP feature detection/setup")
Reported-by: Tao Liu <ltao@redhat.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Tao Liu <ltao@redhat.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230601072043.24439-1-ltao@redhat.com
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Add SNP-specific hooks to the unaccepted memory support in the boot
path (__accept_memory()) and the core kernel (accept_memory()) in order
to support booting SNP guests when unaccepted memory is present. Without
this support, SNP guests will fail to boot and/or panic() when unaccepted
memory is present in the EFI memory map.
The process of accepting memory under SNP involves invoking the hypervisor
to perform a page state change for the page to private memory and then
issuing a PVALIDATE instruction to accept the page.
Since the boot path and the core kernel paths perform similar operations,
move the pvalidate_pages() and vmgexit_psc() functions into sev-shared.c
to avoid code duplication.
Create the new header file arch/x86/boot/compressed/sev.h because adding
the function declaration to any of the existing SEV related header files
pulls in too many other header files, causing the build to fail.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/a52fa69f460fd1876d70074b20ad68210dfc31dd.1686063086.git.thomas.lendacky@amd.com
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Replace multiple __pa()/__va() definitions with a single one in misc.h.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230330114956.20342-2-kirill.shutemov%40linux.intel.com
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The hypervisor can enable various new features (SEV_FEATURES[1:63]) and start a
SNP guest. Some of these features need guest side implementation. If any of
these features are enabled without it, the behavior of the SNP guest will be
undefined. It may fail booting in a non-obvious way making it difficult to
debug.
Instead of allowing the guest to continue and have it fail randomly later,
detect this early and fail gracefully.
The SEV_STATUS MSR indicates features which the hypervisor has enabled. While
booting, SNP guests should ascertain that all the enabled features have guest
side implementation. In case a feature is not implemented in the guest, the
guest terminates booting with GHCB protocol Non-Automatic Exit(NAE) termination
request event, see "SEV-ES Guest-Hypervisor Communication Block Standardization"
document (currently at https://developer.amd.com/wp-content/resources/56421.pdf),
section "Termination Request".
Populate SW_EXITINFO2 with mask of unsupported features that the hypervisor can
easily report to the user.
More details in the AMD64 APM Vol 2, Section "SEV_STATUS MSR".
[ bp:
- Massage.
- Move snp_check_features() call to C code.
Note: the CC:stable@ aspect here is to be able to protect older, stable
kernels when running on newer hypervisors. Or not "running" but fail
reliably and in a well-defined manner instead of randomly. ]
Fixes: cbd3d4f7c4e5 ("x86/sev: Check SEV-SNP features support")
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230118061943.534309-1-nikunj@amd.com
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In some cases, bootloaders will leave boot_params->cc_blob_address
uninitialized rather than zeroing it out. This field is only meant to be
set by the boot/compressed kernel in order to pass information to the
uncompressed kernel when SEV-SNP support is enabled.
Therefore, there are no cases where the bootloader-provided values
should be treated as anything other than garbage. Otherwise, the
uncompressed kernel may attempt to access this bogus address, leading to
a crash during early boot.
Normally, sanitize_boot_params() would be used to clear out such fields
but that happens too late: sev_enable() may have already initialized
it to a valid value that should not be zeroed out. Instead, have
sev_enable() zero it out unconditionally beforehand.
Also ensure this happens for !CONFIG_AMD_MEM_ENCRYPT as well by also
including this handling in the sev_enable() stub function.
[ bp: Massage commit message and comments. ]
Fixes: b190a043c49a ("x86/sev: Add SEV-SNP feature detection/setup")
Reported-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Reported-by: watnuss@gmx.de
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216387
Link: https://lore.kernel.org/r/20220823160734.89036-1-michael.roth@amd.com
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SEV-SNP guests will be provided the location of special 'secrets' and
'CPUID' pages via the Confidential Computing blob. This blob is
provided to the run-time kernel either through a boot_params field that
was initialized by the boot/compressed kernel, or via a setup_data
structure as defined by the Linux Boot Protocol.
Locate the Confidential Computing blob from these sources and, if found,
use the provided CPUID page/table address to create a copy that the
run-time kernel will use when servicing CPUID instructions via a #VC
handler.
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-40-brijesh.singh@amd.com
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Initial/preliminary detection of SEV-SNP is done via the Confidential
Computing blob. Check for it prior to the normal SEV/SME feature
initialization, and add some sanity checks to confirm it agrees with
SEV-SNP CPUID/MSR bits.
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-39-brijesh.singh@amd.com
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The run-time kernel will need to access the Confidential Computing blob
very early during boot to access the CPUID table it points to. At that
stage, it will be relying on the identity-mapped page table set up by
the boot/compressed kernel, so make sure the blob and the CPUID table it
points to are mapped in advance.
[ bp: Massage. ]
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-38-brijesh.singh@amd.com
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SEV-SNP guests will be provided the location of special 'secrets'
'CPUID' pages via the Confidential Computing blob. This blob is
provided to the boot kernel either through an EFI config table entry,
or via a setup_data structure as defined by the Linux Boot Protocol.
Locate the Confidential Computing from these sources and, if found,
use the provided CPUID page/table address to create a copy that the
boot kernel will use when servicing CPUID instructions via a #VC CPUID
handler.
[ bp: s/cpuid/CPUID/ ]
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-36-brijesh.singh@amd.com
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Initial/preliminary detection of SEV-SNP is done via the Confidential
Computing blob. Check for it prior to the normal SEV/SME feature
initialization, and add some sanity checks to confirm it agrees with
SEV-SNP CPUID/MSR bits.
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-35-brijesh.singh@amd.com
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This code will also be used later for SEV-SNP-validated CPUID code in
some cases, so move it to a common helper.
While here, also add a check to terminate in cases where the CPUID
function/subfunction is indexed and the subfunction is non-zero, since
the GHCB MSR protocol does not support non-zero subfunctions.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-32-brijesh.singh@amd.com
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The SEV-SNP guest is required by the GHCB spec to register the GHCB's
Guest Physical Address (GPA). This is because the hypervisor may prefer
that a guest use a consistent and/or specific GPA for the GHCB associated
with a vCPU. For more information, see the GHCB specification section
"GHCB GPA Registration".
If hypervisor can not work with the guest provided GPA then terminate the
guest boot.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lore.kernel.org/r/20220307213356.2797205-17-brijesh.singh@amd.com
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Many of the integrity guarantees of SEV-SNP are enforced through the
Reverse Map Table (RMP). Each RMP entry contains the GPA at which a
particular page of DRAM should be mapped. The VMs can request the
hypervisor to add pages in the RMP table via the Page State Change
VMGEXIT defined in the GHCB specification.
Inside each RMP entry is a Validated flag; this flag is automatically
cleared to 0 by the CPU hardware when a new RMP entry is created for a
guest. Each VM page can be either validated or invalidated, as indicated
by the Validated flag in the RMP entry. Memory access to a private page
that is not validated generates a #VC. A VM must use the PVALIDATE
instruction to validate a private page before using it.
To maintain the security guarantee of SEV-SNP guests, when transitioning
pages from private to shared, the guest must invalidate the pages before
asking the hypervisor to change the page state to shared in the RMP table.
After the pages are mapped private in the page table, the guest must
issue a page state change VMGEXIT to mark the pages private in the RMP
table and validate them.
Upon boot, BIOS should have validated the entire system memory.
During the kernel decompression stage, early_setup_ghcb() uses
set_page_decrypted() to make the GHCB page shared (i.e. clear encryption
attribute). And while exiting from the decompression, it calls
set_page_encrypted() to make the page private.
Add snp_set_page_{private,shared}() helpers that are used by
set_page_{decrypted,encrypted}() to change the page state in the RMP
table.
[ bp: Massage commit message and comments. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-16-brijesh.singh@amd.com
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The Virtual Machine Privilege Level (VMPL) feature in the SEV-SNP
architecture allows a guest VM to divide its address space into four
levels. The level can be used to provide hardware isolated abstraction
layers within a VM. VMPL0 is the highest privilege level, and VMPL3 is
the least privilege level. Certain operations must be done by the VMPL0
software, such as:
* Validate or invalidate memory range (PVALIDATE instruction)
* Allocate VMSA page (RMPADJUST instruction when VMSA=1)
The initial SNP support requires that the guest kernel is running at
VMPL0. Add such a check to verify the guest is running at level 0 before
continuing the boot. There is no easy method to query the current VMPL
level, so use the RMPADJUST instruction to determine whether the guest
is running at the VMPL0.
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-15-brijesh.singh@amd.com
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Version 2 of the GHCB specification added the advertisement of features
that are supported by the hypervisor. If the hypervisor supports SEV-SNP
then it must set the SEV-SNP features bit to indicate that the base
functionality is supported.
Check that feature bit while establishing the GHCB; if failed, terminate
the guest.
Version 2 of the GHCB specification adds several new Non-Automatic Exits
(NAEs), most of them are optional except the hypervisor feature. Now
that the hypervisor feature NAE is implemented, bump the GHCB maximum
supported protocol version.
While at it, move the GHCB protocol negotiation check from the #VC
exception handler to sev_enable() so that all feature detection happens
before the first #VC exception.
While at it, document why the GHCB page cannot be setup from
load_stage2_idt().
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-13-brijesh.singh@amd.com
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The GHCB specification defines the reason code for reason set 0. The
reason codes defined in the set 0 do not cover all possible causes for a
guest to request termination.
The reason sets 1 to 255 are reserved for the vendor-specific codes.
Reserve the reason set 1 for the Linux guest. Define the error codes for
reason set 1 so that one can have meaningful termination reasons and thus
better guest failure diagnosis.
While at it, change sev_es_terminate() to accept a reason set parameter.
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lore.kernel.org/r/20220307213356.2797205-11-brijesh.singh@amd.com
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With upcoming SEV-SNP support, SEV-related features need to be
initialized earlier during boot, at the same point the initial #VC
handler is set up, so that the SEV-SNP CPUID table can be utilized
during the initial feature checks. Also, SEV-SNP feature detection
will rely on EFI helper functions to scan the EFI config table for the
Confidential Computing blob, and so would need to be implemented at
least partially in C.
Currently set_sev_encryption_mask() is used to initialize the
sev_status and sme_me_mask globals that advertise what SEV/SME features
are available in a guest. Rename it to sev_enable() to better reflect
that (SME is only enabled in the case of SEV guests in the
boot/compressed kernel), and move it to just after the stage1 #VC
handler is set up so that it can be used to initialize SEV-SNP as well
in future patches.
While at it, re-implement it as C code so that all SEV feature
detection can be better consolidated with upcoming SEV-SNP feature
detection, which will also be in C.
The 32-bit entry path remains unchanged, as it never relied on the
set_sev_encryption_mask() initialization to begin with.
[ bp: Massage commit message. ]
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-8-brijesh.singh@amd.com
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Update all C code to use the new boot_rdmsr()/boot_wrmsr() helpers
instead of relying on inline assembly.
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-7-brijesh.singh@amd.com
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Shorten macro names for improved readability.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lkml.kernel.org/r/20211110220731.2396491-5-brijesh.singh@amd.com
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SEV-SNP builds upon the SEV-ES functionality while adding new hardware
protection. Version 2 of the GHCB specification adds new NAE events that
are SEV-SNP specific. Rename the sev-es.{ch} to sev.{ch} so that all
SEV* functionality can be consolidated in one place.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Link: https://lkml.kernel.org/r/20210427111636.1207-2-brijesh.singh@amd.com
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