vmmon/vmnet: Build fixes for kernel 6.17.0-14-generic

[MorphyKutay]

Pull Request: vmmon/vmnet – Linux 6.17.0 Compatibility

Overview

These changes enable the vmware-host-modules project to build against Linux kernel 6.17.0-14-generic. Kernel API changes, removed symbols, and objtool warnings have been addressed.

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1. Makefile / Build System

Issue

• driver-config.h could not be found.
• SRCROOT was not propagated correctly in the kernel sub-build.

Solution

• vmmon-only/Makefile and vmnet-only/Makefile: Pass the module directory via VMWARE_MOD_ROOT=$(cd $$PWD && pwd) during the build.
• vmmon-only/Makefile.kernel and vmnet-only/Makefile.kernel: Use VMWARE_MOD_ROOT for MOD_ROOT, and pass -DVMMON/-DVMCORE and include paths via ccflags-y.

Objtool Skipped

• common/phystrack.o: objtool tail-call / fallthrough warnings
• common/task.o: objtool "unexpected end of section" for Task_Switch()
• userif.o (vmnet): objtool csum_partial_copy_nocheck uaccess warning

OBJECT_FILES_NON_STANDARD was added for these files.

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2. Timer API

Issue

• Kernel 6.10+ removed del_timer_sync; it was replaced by timer_delete_sync.
• Implicit declaration errors were produced.

Solution

• vmmon-only/include/compat_timer.h added:
  • #include <linux/timer.h>
  • For LINUX_VERSION_CODE >= KERNEL_VERSION(6, 10, 0): #define del_timer_sync timer_delete_sync
• Included compat_timer.h in driver.c and hostif.c.

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3. Page Table API

Issue

• Kernel 6.9+ removed pgd_large, p4d_large, pud_large, and pmd_large.
• The new equivalents are pgd_leaf, p4d_leaf, pud_leaf, and pmd_leaf.
• On x86 only pud_leaf and pmd_leaf exist; pgd_leaf and p4d_leaf are not defined.

Solution

• vmmon-only/include/compat_pgtable.h: For 6.9+, map compat_pud_large → pud_leaf and compat_pmd_large → pmd_leaf; use (0) for compat_pgd_large and compat_p4d_large on x86.
• vmmon-only/include/pgtbl.h: Replaced direct uses with the compat_* macros.

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4. MSR API

Issue

• rdmsrl_safe is no longer available; rdmsrq_safe should be used instead.

Solution

• hostif.c: Replaced rdmsrl_safe with rdmsrq_safe and added #include <asm/msr.h>.

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5. Crosspage Assembly (RETHUNK / objtool)

Issue

• Objtool reported: "naked return found in MITIGATION_RETHUNK build".
• Plain ret must use the return thunk (__x86_return_thunk).
• GDT_SIZE conflicted with a kernel header definition.

Solution

• crosspage.c: Added #include <asm/linkage.h> and replaced ret with ASM_RET.
• segs.h: Renamed GDT_SIZE → VMMON_GDT_SIZE and GDT_LIMIT → VMMON_GDT_LIMIT.
• crosspage.c: Updated references to use VMMON_GDT_LIMIT.

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6. random_get_entropy_fallback (vmx86.c)

Issue

• The inline function in asm/timex.h calls random_get_entropy_fallback().
• This function was not declared in the module build context.

Solution

• vmx86.c: Added extern unsigned long random_get_entropy_fallback(void); before including asm/timex.h.

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7. vmnet: dev_base_lock

Issue

• Kernel 6.6+ removed dev_base_lock.

Solution

• vmnet-only/vmnetInt.h: For 6.6+, map dev_lock_list() → rtnl_lock() and dev_unlock_list() → rtnl_unlock().

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Modified / Added Files

File	Change
vmmon-only/Makefile	VMWARE_MOD_ROOT propagation
vmmon-only/Makefile.kernel	MOD_ROOT, ccflags-y, OBJECT_FILES_NON_STANDARD
vmnet-only/Makefile	VMWARE_MOD_ROOT propagation
vmnet-only/Makefile.kernel	MOD_ROOT, OBJECT_FILES_NON_STANDARD
vmmon-only/include/compat_timer.h	New file
vmmon-only/include/compat_pgtable.h	6.9+ page table compatibility
vmmon-only/include/pgtbl.h	compat_* macro usage
vmmon-only/include/segs.h	VMMON_GDT_SIZE, VMMON_GDT_LIMIT
vmmon-only/linux/driver.c	compat_timer.h include
vmmon-only/linux/hostif.c	compat_timer.h, asm/msr.h, rdmsrq_safe
vmmon-only/common/crosspage.c	ASM_RET, linkage.h, GDT_LIMIT
vmmon-only/common/vmx86.c	random_get_entropy_fallback extern
vmnet-only/vmnetInt.h	dev_base_lock → rtnl_lock (6.6+)

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Testing

• make successfully builds both vmmon and vmnet modules.
• make install installs them under /lib/modules/6.17.0-14-generic/misc/.
• Target kernel: 6.17.0-14-generic (Ubuntu).

[eku]

I'm wondering why changes to 168 files are needed to fix some problems with kernel API?

[mkonnov]

I can confirm it worked for 6.17.0-19-generic against VMware Workstation 17.5.1 build-23298084