linux.git/arch/x86/include/uapi/asm/bootparam.h, branch v5.19

x86/boot: Fix the setup data types max limit

2022-07-10T09:17:40+00:00

Commit in Fixes forgot to change the SETUP_TYPE_MAX definition which
contains the highest valid setup data type.

Correct that.

Fixes: 5ea98e01ab52 ("x86/boot: Add Confidential Computing type to setup_data")
Signed-off-by: Borislav Petkov 
Link: https://lore.kernel.org/r/ddba81dd-cc92-699c-5274-785396a17fb5@zytor.com

x86/boot: Add a pointer to Confidential Computing blob in bootparams

2022-04-07T14:47:11+00:00

The previously defined Confidential Computing blob is provided to the
kernel via a setup_data structure or EFI config table entry. Currently,
these are both checked for by boot/compressed kernel to access the CPUID
table address within it for use with SEV-SNP CPUID enforcement.

To also enable that enforcement for the run-time kernel, similar
access to the CPUID table is needed early on while it's still using
the identity-mapped page table set up by boot/compressed, where global
pointers need to be accessed via fixup_pointer().

This isn't much of an issue for accessing setup_data, and the EFI config
table helper code currently used in boot/compressed *could* be used in
this case as well since they both rely on identity-mapping. However, it
has some reliance on EFI helpers/string constants that would need to be
accessed via fixup_pointer(), and fixing it up while making it shareable
between boot/compressed and run-time kernel is fragile and introduces a
good bit of ugliness.

Instead, add a boot_params->cc_blob_address pointer that the
boot/compressed kernel can initialize so that the run-time kernel can
access the CC blob from there instead of re-scanning the EFI config
table.

Also document these in Documentation/x86/zero-page.rst. While there,
add missing documentation for the acpi_rsdp_addr field, which serves a
similar purpose in providing the run-time kernel a pointer to the ACPI
RSDP table so that it does not need to [re-]scan the EFI configuration
table.

  [ bp: Fix typos, massage commit message. ]

Signed-off-by: Michael Roth 
Signed-off-by: Brijesh Singh 
Signed-off-by: Borislav Petkov 
Link: https://lore.kernel.org/r/20220307213356.2797205-34-brijesh.singh@amd.com

x86/boot: Add Confidential Computing type to setup_data

2022-04-07T14:46:33+00:00

While launching encrypted guests, the hypervisor may need to provide
some additional information during the guest boot. When booting under an
EFI-based BIOS, the EFI configuration table contains an entry for the
confidential computing blob that contains the required information.

To support booting encrypted guests on non-EFI VMs, the hypervisor
needs to pass this additional information to the guest kernel using a
different method.

For this purpose, introduce SETUP_CC_BLOB type in setup_data to hold
the physical address of the confidential computing blob location. The
boot loader or hypervisor may choose to use this method instead of an
EFI configuration table. The CC blob location scanning should give
preference to a setup_data blob over an EFI configuration table.

In AMD SEV-SNP, the CC blob contains the address of the secrets and
CPUID pages. The secrets page includes information such as a VM to PSP
communication key and the CPUID page contains PSP-filtered CPUID values.
Define the AMD SEV confidential computing blob structure.

While at it, define the EFI GUID for the confidential computing blob.

  [ bp: Massage commit message, mark struct __packed. ]

Signed-off-by: Brijesh Singh 
Signed-off-by: Borislav Petkov 
Acked-by: Ard Biesheuvel 
Link: https://lore.kernel.org/r/20220307213356.2797205-30-brijesh.singh@amd.com

x86: Fix various typos in comments

2021-03-18T14:31:53+00:00

Fix ~144 single-word typos in arch/x86/ code comments.

Doing this in a single commit should reduce the churn.

Signed-off-by: Ingo Molnar 
Cc: Borislav Petkov 
Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Paolo Bonzini 
Cc: Bjorn Helgaas 
Cc: linux-kernel@vger.kernel.org

x86: bootparam.h: Delete duplicated word

2020-07-26T10:47:22+00:00

Delete the repeated word "for".

Signed-off-by: Randy Dunlap 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20200726004124.20618-2-rdunlap@infradead.org

Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-11-26T17:52:37+00:00

Pull x86 platform updates from Ingo Molnar:
 "UV platform updates (with a 'hubless' variant) and Jailhouse updates
  for better UART support"

* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/jailhouse: Only enable platform UARTs if available
  x86/jailhouse: Improve setup data version comparison
  x86/platform/uv: Account for UV Hubless in is_uvX_hub Ops
  x86/platform/uv: Check EFI Boot to set reboot type
  x86/platform/uv: Decode UVsystab Info
  x86/platform/uv: Add UV Hubbed/Hubless Proc FS Files
  x86/platform/uv: Setup UV functions for Hubless UV Systems
  x86/platform/uv: Add return code to UV BIOS Init function
  x86/platform/uv: Return UV Hubless System Type
  x86/platform/uv: Save OEM_ID from ACPI MADT probe

x86/boot: Introduce setup_indirect

2019-11-12T15:21:15+00:00

The setup_data is a bit awkward to use for extremely large data objects,
both because the setup_data header has to be adjacent to the data object
and because it has a 32-bit length field. However, it is important that
intermediate stages of the boot process have a way to identify which
chunks of memory are occupied by kernel data. Thus introduce an uniform
way to specify such indirect data as setup_indirect struct and
SETUP_INDIRECT type.

And finally bump setup_header version in arch/x86/boot/header.S.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Acked-by: Konrad Rzeszutek Wilk 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-4-daniel.kiper@oracle.com

x86/boot: Introduce kernel_info.setup_type_max

2019-11-12T15:16:54+00:00

This field contains maximal allowed type for setup_data.

Do not bump setup_header version in arch/x86/boot/header.S because it
will be followed by additional changes coming into the Linux/x86 boot
protocol.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-3-daniel.kiper@oracle.com

x86/boot: Introduce kernel_info

2019-11-12T15:10:34+00:00

The relationships between the headers are analogous to the various data
sections:

  setup_header = .data
  boot_params/setup_data = .bss

What is missing from the above list? That's right:

  kernel_info = .rodata

We have been (ab)using .data for things that could go into .rodata or .bss for
a long time, for lack of alternatives and -- especially early on -- inertia.
Also, the BIOS stub is responsible for creating boot_params, so it isn't
available to a BIOS-based loader (setup_data is, though).

setup_header is permanently limited to 144 bytes due to the reach of the
2-byte jump field, which doubles as a length field for the structure, combined
with the size of the "hole" in struct boot_params that a protected-mode loader
or the BIOS stub has to copy it into. It is currently 119 bytes long, which
leaves us with 25 very precious bytes. This isn't something that can be fixed
without revising the boot protocol entirely, breaking backwards compatibility.

boot_params proper is limited to 4096 bytes, but can be arbitrarily extended
by adding setup_data entries. It cannot be used to communicate properties of
the kernel image, because it is .bss and has no image-provided content.

kernel_info solves this by providing an extensible place for information about
the kernel image. It is readonly, because the kernel cannot rely on a
bootloader copying its contents anywhere, but that is OK; if it becomes
necessary it can still contain data items that an enabled bootloader would be
expected to copy into a setup_data chunk.

Do not bump setup_header version in arch/x86/boot/header.S because it
will be followed by additional changes coming into the Linux/x86 boot
protocol.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-2-daniel.kiper@oracle.com

x86/jailhouse: Only enable platform UARTs if available

2019-10-10T13:43:59+00:00

ACPI tables aren't available if Linux runs as guest of the hypervisor
Jailhouse. This makes the 8250 driver probe for all platform UARTs as it
assumes that all UARTs are present in case of !ACPI. Jailhouse will stop
execution of Linux guest due to port access violation.

So far, these access violations were solved by tuning the 8250.nr_uarts
cmdline parameter, but this has limitations: Only consecutive platform
UARTs can be mapped to Linux, and only in the sequence 0x3f8, 0x2f8,
0x3e8, 0x2e8.

Beginning from setup_data version 2, Jailhouse will place information of
available platform UARTs in setup_data. This allows for selective
activation of platform UARTs.

Query setup_data version and only activate available UARTS. This
patch comes with backward compatibility, and will still support older
setup_data versions. In case of older setup_data versions, Linux falls
back to the old behaviour.

Signed-off-by: Ralf Ramsauer 
Signed-off-by: Borislav Petkov 
Reviewed-by: Jan Kiszka 
Cc: Baoquan He 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: jailhouse-dev@googlegroups.com
Cc: Juergen Gross 
Cc: "Kirill A. Shutemov" 
Cc: Thomas Gleixner 
Cc: x86-ml 
Link: https://lkml.kernel.org/r/20191010102102.421035-3-ralf.ramsauer@oth-regensburg.de