[SIG CLOUD 8] rebase custom changes to 4.18.0-553.47.1.el8_10 #208
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…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://raw.githubusercontent.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>
PlaidCat
requested review from
Kemotaha,
bmastbergen,
kerneltoast and
thefossguy-ciq
bmastbergen
approved these changes
Apr 10, 2025
|
@bmastbergen, since @PlaidCat is out, do you mind if I go ahead and merge this? I'm working on the dist-git side of things. |
bmastbergen
merged commit 4727168
into
sig-cloud-8/4.18.0-553.47.1.el8_10
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