github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-28 01:55:51 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

x86/virt/seamldr: Add module update locking

Browse Source 
TDX metadata like the version number changes during a module update.
Add functions to lock out module updates.

The current stop_machine() implementation uses worker threads. The
scheduler actually does a full, normal context switch over to that
thread. preempt_disable() obviously inhibits that context switch and
thus, locks out stop_machine() users like the module update.

Thanks to Chao for the idea of using preempt_disable().

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
This commit is contained in:
Dave Hansen 2026-05-22 08:43:02 -07:00
parent b344c50a1a
commit 6e97c234cd
2 changed files with 18 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/seamldr.h
View File

@ -32,5 +32,7 @@ static_assert(sizeof(struct seamldr_info) == 256);
int seamldr_get_info(struct seamldr_info *seamldr_info);
int seamldr_install_module(const u8 *data, u32 data_len);
void seamldr_lock_module_update(void);
void seamldr_unlock_module_update(void);
#endif /* _ASM_X86_SEAMLDR_H */

16
arch/x86/virt/vmx/tdx/seamldr.c
View File

@ -350,3 +350,19 @@ int seamldr_install_module(const u8 *data, u32 data_len)
return ret;
}
EXPORT_SYMBOL_FOR_MODULES(seamldr_install_module, "tdx-host");
/*
* stop_machine() does not interrupt preemption-disabled regions.
* Simply disabling preempt prevents updates.
*/
void seamldr_lock_module_update(void)
{
preempt_disable();
}
EXPORT_SYMBOL_FOR_MODULES(seamldr_lock_module_update, "tdx-host");
void seamldr_unlock_module_update(void)
{
preempt_enable();
}
EXPORT_SYMBOL_FOR_MODULES(seamldr_unlock_module_update, "tdx-host");