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[SIG-CLOUD-8] Rebase custom chages to 4.18.0-553.58.1.el8_10 #392

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@PlaidCat PlaidCat commented Jul 2, 2025

Update process (This kernel CentOS base for 4.18.0-553)

  • Kernel History Rebuild Process for all src.rpms hosted by RESF
  • Create sig-cloud-8/4.18.0-553.53.1.el8_10 branch
  • Check if any maintained code is included in the new el release.
  • Cherry-pick all code from previous branch into new branch (skipping unneeded code)
    • Fix conflicts as they arise
  • Build and Test

Removed Commits

None

Rebase Results

[jmaple@devbox code]$ cat RR.553.58.log
[rolling release update] Rolling Product:  sig-cloud-8
[rolling release update] Checking out branch:  sig-cloud-8/4.18.0-553.56.1.el8_10
[rolling release update] Gathering all the RESF kernel Tags
b'1ad2baf0efe1 (tag: resf_kernel-4.18.0-553.56.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.56.1.el8_10'
b'6f9106f46020 (tag: resf_kernel-4.18.0-553.54.1.el8_10, origin/rocky8_10_rebuild) Rebuild rocky8_10 with kernel-4.18.0-553.54.1.el8_10'
b'32f87806bbd4 (tag: resf_kernel-4.18.0-553.53.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.53.1.el8_10'
b'e99974a02d4f (tag: resf_kernel-4.18.0-553.52.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.52.1.el8_10'
b'bda8b8ebc7b7 (tag: resf_kernel-4.18.0-553.51.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.51.1.el8_10'
b'32fa0f457b22 (tag: resf_kernel-4.18.0-553.50.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.50.1.el8_10'
b'01aef32f4a9b (tag: resf_kernel-4.18.0-553.47.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.47.1.el8_10'
b'e622eefa811c (tag: resf_kernel-4.18.0-553.46.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.46.1.el8_10'
b'f025379c5d08 (tag: resf_kernel-4.18.0-553.45.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.45.1.el8_10'
b'16dc63866351 (tag: resf_kernel-4.18.0-553.44.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.44.1.el8_10'
b'5b691f92af91 (tag: resf_kernel-4.18.0-553.42.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.42.1.el8_10'
b'0dbf87712115 (tag: resf_kernel-4.18.0-553.40.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.40.1.el8_10'
b'26d9a06a4a5f (tag: resf_kernel-4.18.0-553.37.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.37.1.el8_10'
b'4673f9b8360d (tag: resf_kernel-4.18.0-553.36.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.36.1.el8_10'
b'7e4fb1a14fcd (tag: resf_kernel-4.18.0-553.34.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.34.1.el8_10'
b'72ceaa9ab31e (tag: resf_kernel-4.18.0-553.33.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.33.1.el8_10'
b'0570eb3e10e4 (tag: resf_kernel-4.18.0-553.32.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.32.1.el8_10'
b'657b4d21132b (tag: resf_kernel-4.18.0-553.30.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.30.1.el8_10'
b'c1970aa3f569 (tag: resf_kernel-4.18.0-553.27.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.27.1.el8_10'
b'8bf75aa29fd0 (tag: resf_kernel-4.18.0-553.22.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.22.1.el8_10'
b'ea7f8a5da93b (tag: resf_kernel-4.18.0-553.16.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.16.1.el8_10'
b'2fd9e62e45de (tag: resf_kernel-4.18.0-553.8.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.8.1.el8_10'
b'a2d1b1a06ff8 (tag: resf_kernel-4.18.0-553.5.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.5.1.el8_10'
b'4533b19a3a3e (tag: resf_kernel-4.18.0-553.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.el8_10'
[rolling release update] Old Rolling Branch Tags:  [b'1ad2baf0efe1', b'6f9106f46020', b'32f87806bbd4', b'e99974a02d4f', b'bda8b8ebc7b7', b'32fa0f457b22', b'01aef32f4a9b', b'e622eefa811c', b'f025379c5d08', b'16dc63866351', b'5b691f92af91', b'0dbf87712115', b'26d9a06a4a5f', b'4673f9b8360d', b'7e4fb1a14fcd', b'72ceaa9ab31e', b'0570eb3e10e4', b'657b4d21132b', b'c1970aa3f569', b'8bf75aa29fd0', b'ea7f8a5da93b', b'2fd9e62e45de', b'a2d1b1a06ff8', b'4533b19a3a3e']
[rolling release update] Checking out branch:  rocky8_10
[rolling release update] Gathering all the RESF kernel Tags
b'2e416d167715 (HEAD -> rocky8_10, tag: resf_kernel-4.18.0-553.58.1.el8_10, origin/rocky8_10) Rebuild rocky8_10 with kernel-4.18.0-553.58.1.el8_10'
b'1ad2baf0efe1 (tag: resf_kernel-4.18.0-553.56.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.56.1.el8_10'
b'6f9106f46020 (tag: resf_kernel-4.18.0-553.54.1.el8_10, origin/rocky8_10_rebuild) Rebuild rocky8_10 with kernel-4.18.0-553.54.1.el8_10'
b'32f87806bbd4 (tag: resf_kernel-4.18.0-553.53.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.53.1.el8_10'
b'e99974a02d4f (tag: resf_kernel-4.18.0-553.52.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.52.1.el8_10'
b'bda8b8ebc7b7 (tag: resf_kernel-4.18.0-553.51.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.51.1.el8_10'
b'32fa0f457b22 (tag: resf_kernel-4.18.0-553.50.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.50.1.el8_10'
b'01aef32f4a9b (tag: resf_kernel-4.18.0-553.47.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.47.1.el8_10'
b'e622eefa811c (tag: resf_kernel-4.18.0-553.46.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.46.1.el8_10'
b'f025379c5d08 (tag: resf_kernel-4.18.0-553.45.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.45.1.el8_10'
b'16dc63866351 (tag: resf_kernel-4.18.0-553.44.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.44.1.el8_10'
b'5b691f92af91 (tag: resf_kernel-4.18.0-553.42.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.42.1.el8_10'
b'0dbf87712115 (tag: resf_kernel-4.18.0-553.40.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.40.1.el8_10'
b'26d9a06a4a5f (tag: resf_kernel-4.18.0-553.37.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.37.1.el8_10'
b'4673f9b8360d (tag: resf_kernel-4.18.0-553.36.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.36.1.el8_10'
b'7e4fb1a14fcd (tag: resf_kernel-4.18.0-553.34.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.34.1.el8_10'
b'72ceaa9ab31e (tag: resf_kernel-4.18.0-553.33.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.33.1.el8_10'
b'0570eb3e10e4 (tag: resf_kernel-4.18.0-553.32.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.32.1.el8_10'
b'657b4d21132b (tag: resf_kernel-4.18.0-553.30.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.30.1.el8_10'
b'c1970aa3f569 (tag: resf_kernel-4.18.0-553.27.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.27.1.el8_10'
b'8bf75aa29fd0 (tag: resf_kernel-4.18.0-553.22.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.22.1.el8_10'
b'ea7f8a5da93b (tag: resf_kernel-4.18.0-553.16.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.16.1.el8_10'
b'2fd9e62e45de (tag: resf_kernel-4.18.0-553.8.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.8.1.el8_10'
b'a2d1b1a06ff8 (tag: resf_kernel-4.18.0-553.5.1.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.5.1.el8_10'
b'4533b19a3a3e (tag: resf_kernel-4.18.0-553.el8_10) Rebuild rocky8_10 with kernel-4.18.0-553.el8_10'
[rolling release update] New Base Branch Tags:  [b'2e416d167715', b'1ad2baf0efe1', b'6f9106f46020', b'32f87806bbd4', b'e99974a02d4f', b'bda8b8ebc7b7', b'32fa0f457b22', b'01aef32f4a9b', b'e622eefa811c', b'f025379c5d08', b'16dc63866351', b'5b691f92af91', b'0dbf87712115', b'26d9a06a4a5f', b'4673f9b8360d', b'7e4fb1a14fcd', b'72ceaa9ab31e', b'0570eb3e10e4', b'657b4d21132b', b'c1970aa3f569', b'8bf75aa29fd0', b'ea7f8a5da93b', b'2fd9e62e45de', b'a2d1b1a06ff8', b'4533b19a3a3e']
[rolling release update] Latest RESF tag sha:  b'1ad2baf0efe1'
"1ad2baf0efe157120b3448abdfcf48736e86508f Rebuild rocky8_10 with kernel-4.18.0-553.56.1.el8_10"
[rolling release update] Checking out old rolling branch:  sig-cloud-8/4.18.0-553.56.1.el8_10
[rolling release update] Finding the CIQ Kernel and Associated Upstream commits between the last resf tag and HEAD
[rolling release update] Last RESF tag sha:  b'1ad2baf0efe1'
[rolling release update] Total Commit in old branch:  5
{ "CIQ COMMMIT" : "UPSTREAM COMMMIT" }
{
  "f7f119891ca898b58e12aa1202d21b2e8285aa50": "2a38e4ca302280fdcce370ba2bee79bac16c4587",
  "753cc5542703ccb7fcba4e491aecdd015b6a1ab6": "95bfb35269b2e85cff0dd2c957b2d42ebf95ae5f",
  "dbcaa7baf4515a446e2ed719a50a74826ae71439": "9a458198eba98b7207669a166e64d04b04cb651b",
  "44ad6a811ca31e95f14428749053727e4247ddc5": "3e32552652917f10c0aa8ac75cdc8f0b8d257dec",
  "c4f121f8c1589d8d92ba1c6e35ebe7805a977cb0": "fbf6449f84bf5e4ad09f2c09ee70ed7d629b5ff6"
}
[rolling release update] Checking out new base branch:  rocky8_10
[rolling release update] Finding the kernel version for the new rolling release
b'2e416d167715 (HEAD -> rocky8_10, tag: resf_kernel-4.18.0-553.58.1.el8_10, origin/rocky8_10) Rebuild rocky8_10 with kernel-4.18.0-553.58.1.el8_10'
<re.Match object; span=(0, 72), match=b'2e416d167715 (HEAD -> rocky8_10, tag: resf_kerne>
[rolling release update} New Branch to create  sig-cloud-8/4.18.0-553.58.1.el8_10
[rolling release update] Check if branch Exists:  sig-cloud-8/4.18.0-553.58.1.el8_10
Branch sig-cloud-8/4.18.0-553.58.1.el8_10 does not exists creating
[rolling release update] Creating new branch for PR:  jmaple_sig-cloud-8/4.18.0-553.58.1.el8_10
[rolling release update] Creating Map of all new commits from last rolling release fork
[rolling release update] Total Commit in new branch:  53
{ "CIQ COMMMIT" : "UPSTREAM COMMMIT" }
Printing first 5 and last 5 commits
{
  "2e416d1677153d818b7930066693f5b696873dc5": "",
  "77874c7fe949cc2451ff3d6861afc0c7e28c12bb": "628e6d18930bbd21f2d4562228afe27694f66da9",
  "59ff24e84dbb012b0a84503ab4f63f60690d2b43": "3c8ffcd248da34fc41e52a46e51505900115fc2a",
  "c92854d6d2e3d5c3a7612a9aae3a6b50151e7473": "482ad2a4ace2740ca0ff1cbc8f3c7f862f3ab507",
  "6510a3de91eb02c80245f9d3cee74738d6053fc3": "2034d90ae41ae93e30d492ebcf1f06f97a9cfba6"
}
{
  "25900119ca9642f3e3cc1c1f2782ea0f5a32a7b2": "bcb5d6c769039c8358a2359e7c3ea5d97ce93108",
  "d8d6896b7a4f5d1cf87103363f812fcfd19c487d": "0d48566d4b58946c8e1b0baac0347616060a81c9",
  "6bd016b86f50a58099e001af182fa8e5a4f9ff41": "12c30f33cc6769bf411088a2872843c4f9ea32f9",
  "949da0e7e5ea93e8187af71c5371bec30df802a8": "3d6cc9898efdfb062efb74dc18cfc700e082f5d5",
  "2b92079db1888ed6b5fb2d0af08da86f993afcc6": "4a74da044ec9ec8679e6beccc4306b936b62873f"
}
[rolling release update] Checking if any of the commits from the old rolling release are already present in the new base branch
[rolling release update] Removing commits from the new branch
[rolling release update] Applying the remaining commits to the new branch
Applying commit  "c4f121f8c1589d8d92ba1c6e35ebe7805a977cb0 x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach"
Applying commit  "44ad6a811ca31e95f14428749053727e4247ddc5 x86/boot: Move x86_cache_alignment initialization to correct spot"
Applying commit  "dbcaa7baf4515a446e2ed719a50a74826ae71439 x86/cpu: Allow reducing x86_phys_bits during early_identify_cpu()"
Applying commit  "753cc5542703ccb7fcba4e491aecdd015b6a1ab6 x86/cpu: Get rid of an unnecessary local variable in get_cpu_address_sizes()"
Applying commit  "f7f119891ca898b58e12aa1202d21b2e8285aa50 x86/cpu: Provide default cache line size if not enumerated"

Build

[jmaple@devbox code]$ egrep -B 5 -A 5 "\[TIMER\]|^Starting Build" kbuild.SCN8.resf_kernel-4.18.0-553.58.1.el8_10.log
/mnt/code/kernel-src-tree
no .config file found, moving on
[TIMER]{MRPROPER}: 0s
x86_64 architecture detected, copying config
'configs/kernel-x86_64.config' -> '.config'
Setting Local Version for build
CONFIG_LOCALVERSION="-jmaple_sig-cloud-8_4.18.0-553.58.1.el8_10-7e20e9e9cbf5"
Making olddefconfig
--
  HOSTLD  scripts/kconfig/conf
scripts/kconfig/conf  --olddefconfig Kconfig
#
# configuration written to .config
#
Starting Build
scripts/kconfig/conf  --syncconfig Kconfig
  SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
  SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
--
  LD [M]  sound/usb/usx2y/snd-usb-usx2y.ko
  LD [M]  sound/virtio/virtio_snd.ko
  LD [M]  sound/x86/snd-hdmi-lpe-audio.ko
  LD [M]  sound/xen/snd_xen_front.ko
  LD [M]  virt/lib/irqbypass.ko
[TIMER]{BUILD}: 1913s
Making Modules
  INSTALL arch/x86/crypto/blowfish-x86_64.ko
  INSTALL arch/x86/crypto/camellia-aesni-avx-x86_64.ko
  INSTALL arch/x86/crypto/camellia-x86_64.ko
  INSTALL arch/x86/crypto/camellia-aesni-avx2.ko
--
  INSTALL sound/virtio/virtio_snd.ko
  INSTALL sound/x86/snd-hdmi-lpe-audio.ko
  INSTALL sound/xen/snd_xen_front.ko
  INSTALL virt/lib/irqbypass.ko
  DEPMOD  4.18.0-jmaple_sig-cloud-8_4.18.0-553.58.1.el8_10-7e20e9e9cbf5+
[TIMER]{MODULES}: 13s
Making Install
sh ./arch/x86/boot/install.sh 4.18.0-jmaple_sig-cloud-8_4.18.0-553.58.1.el8_10-7e20e9e9cbf5+ arch/x86/boot/bzImage \
	System.map "/boot"
[TIMER]{INSTALL}: 20s
Checking kABI
Checking kABI
kABI check passed
Setting Default Kernel to /boot/vmlinuz-4.18.0-jmaple_sig-cloud-8_4.18.0-553.58.1.el8_10-7e20e9e9cbf5+ and Index to 0
Hopefully Grub2.0 took everything ... rebooting after time metrices
[TIMER]{MRPROPER}: 0s
[TIMER]{BUILD}: 1913s
[TIMER]{MODULES}: 13s
[TIMER]{INSTALL}: 20s
[TIMER]{TOTAL} 1950s
Rebooting in 10 seconds

KSelfTest

[jmaple@devbox code]$ ls kselftest.4.18.0-jmaple_sig-cloud-8_4.18.0-553.56.1.el8_10-f7f119891ca8+.log kselftest.SCN8.4.18.0-jmaple_sig-cloud-8_4.18.0-553.58.1.el8_10-7e20e9e9cbf5+.log | while read line; do echo $line; grep '^ok ' $line | wc -l; done
kselftest.4.18.0-jmaple_sig-cloud-8_4.18.0-553.56.1.el8_10-f7f119891ca8+.log
206
kselftest.SCN8.4.18.0-jmaple_sig-cloud-8_4.18.0-553.58.1.el8_10-7e20e9e9cbf5+.log
206

ciq-sahlberg and others added 5 commits July 1, 2025 18:27
…tead of a two-phase approach

jira roc-2673
commit fbf6449

Instead of setting x86_virt_bits to a possibly-correct value and then
correcting it later, do all the necessary checks before setting it.

At this point, the #VC handler references boot_cpu_data.x86_virt_bits,
and in the previous version, it would be triggered by the CPUIDs between
the point at which it is set to 48 and when it is set to the correct
value.

    Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
    Signed-off-by: Adam Dunlap <acdunlap@google.com>
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Tested-by: Jacob Xu <jacobhxu@google.com>
    Link: https://lore.kernel.org/r/20230912002703.3924521-3-acdunlap@google.com

Signed-off-by: Ronnie Sahlberg <rsahlberg@ciq.com>
Signed-off-by: Jonathan Maple <jmaple@ciq.com>
jira roc-2673
commit 3e32552

c->x86_cache_alignment is initialized from c->x86_clflush_size.
However, commit fbf6449 moved c->x86_clflush_size initialization
to later in boot without moving the c->x86_cache_alignment assignment:

  fbf6449 ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")

This presumably left c->x86_cache_alignment set to zero for longer
than it should be.

The result was an oops on 32-bit kernels while accessing a pointer
at 0x20.  The 0x20 came from accessing a structure member at offset
0x10 (buffer->cpumask) from a ZERO_SIZE_PTR=0x10.  kmalloc() can
evidently return ZERO_SIZE_PTR when it's given 0 as its alignment
requirement.

Move the c->x86_cache_alignment initialization to be after
c->x86_clflush_size has an actual value.

    Fixes: fbf6449 ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")
    Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Tested-by: Nathan Chancellor <nathan@kernel.org>
    Link: https://lore.kernel.org/r/20231002220045.1014760-1-dave.hansen@linux.intel.com
    (cherry picked from commit 3e32552)
Signed-off-by: Ronnie Sahlberg <rsahlberg@ciq.com>

Signed-off-by: Jonathan Maple <jmaple@ciq.com>
jira LE-2183
bug-fix x86/sev-es: Set x86_virt_bits
commit-author Paolo Bonzini <pbonzini@redhat.com>
commit 9a45819

In commit fbf6449 ("x86/sev-es: Set x86_virt_bits to the correct
value straight away, instead of a two-phase approach"), the initialization
of c->x86_phys_bits was moved after this_cpu->c_early_init(c).  This is
incorrect because early_init_amd() expected to be able to reduce the
value according to the contents of CPUID leaf 0x8000001f.

Fortunately, the bug was negated by init_amd()'s call to early_init_amd(),
which does reduce x86_phys_bits in the end.  However, this is very
late in the boot process and, most notably, the wrong value is used for
x86_phys_bits when setting up MTRRs.

To fix this, call get_cpu_address_sizes() as soon as X86_FEATURE_CPUID is
set/cleared, and c->extended_cpuid_level is retrieved.

Fixes: fbf6449 ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")
	Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
	Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
	Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240131230902.1867092-2-pbonzini%40redhat.com
(cherry picked from commit 9a45819)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>
Signed-off-by: Jonathan Maple <jmaple@ciq.com>
…sizes()

jira LE-2183
bug-fix-prereq x86/sev-es: Set x86_virt_bits
commit-author Borislav Petkov (AMD) <bp@alien8.de>
commit 95bfb35

Drop 'vp_bits_from_cpuid' as it is not really needed.

No functional changes.

	Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
	Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240316120706.4352-1-bp@alien8.de
(cherry picked from commit 95bfb35)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>
Signed-off-by: Jonathan Maple <jmaple@ciq.com>
jira LE-2183
bug-fix x86/sev-es: Set x86_virt_bits
commit-author Dave Hansen <dave.hansen@linux.intel.com>
commit 2a38e4c

tl;dr: CPUs with CPUID.80000008H but without CPUID.01H:EDX[CLFSH]
will end up reporting cache_line_size()==0 and bad things happen.
Fill in a default on those to avoid the problem.

Long Story:

The kernel dies a horrible death if c->x86_cache_alignment (aka.
cache_line_size() is 0.  Normally, this value is populated from
c->x86_clflush_size.

Right now the code is set up to get c->x86_clflush_size from two
places.  First, modern CPUs get it from CPUID.  Old CPUs that don't
have leaf 0x80000008 (or CPUID at all) just get some sane defaults
from the kernel in get_cpu_address_sizes().

The vast majority of CPUs that have leaf 0x80000008 also get
->x86_clflush_size from CPUID.  But there are oddballs.

Intel Quark CPUs[1] and others[2] have leaf 0x80000008 but don't set
CPUID.01H:EDX[CLFSH], so they skip over filling in ->x86_clflush_size:

	cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
	if (cap0 & (1<<19))
		c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;

So they: land in get_cpu_address_sizes() and see that CPUID has level
0x80000008 and jump into the side of the if() that does not fill in
c->x86_clflush_size.  That assigns a 0 to c->x86_cache_alignment, and
hilarity ensues in code like:

        buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
                         GFP_KERNEL);

To fix this, always provide a sane value for ->x86_clflush_size.

Big thanks to Andy Shevchenko for finding and reporting this and also
providing a first pass at a fix. But his fix was only partial and only
worked on the Quark CPUs.  It would not, for instance, have worked on
the QEMU config.

1. https://github.com/InstLatx64/InstLatx64/master/GenuineIntel/GenuineIntel0000590_Clanton_03_CPUID.txt
2. You can also get this behavior if you use "-cpu 486,+clzero"
   in QEMU.

[ dhansen: remove 'vp_bits_from_cpuid' reference in changelog
	   because bpetkov brutally murdered it recently. ]

Fixes: fbf6449 ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")
	Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
	Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
	Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
	Tested-by: Jörn Heusipp <osmanx@heusipp.de>
	Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240516173928.3960193-1-andriy.shevchenko@linux.intel.com/
Link: https://lore.kernel.org/lkml/5e31cad3-ad4d-493e-ab07-724cfbfaba44@heusipp.de/
Link: https://lore.kernel.org/all/20240517200534.8EC5F33E%40davehans-spike.ostc.intel.com
(cherry picked from commit 2a38e4c)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>
Signed-off-by: Jonathan Maple <jmaple@ciq.com>
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@PlaidCat PlaidCat merged commit 7e20e9e into sig-cloud-8/4.18.0-553.58.1.el8_10 Jul 2, 2025
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@PlaidCat PlaidCat deleted the jmaple_sig-cloud-8/4.18.0-553.58.1.el8_10 branch July 2, 2025 19:16
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