From: Patrick Roy patrick.roy@linux.dev
After direct map removal, a TLB flush must be done to ensure that the just-unmapped memory cannot be accessed through stale TLB entries.
This export is only needed on x86, as arm64 (the only other architecture supporting guest_memfd currently) does not allow building KVM as a module.
Cc: Thomas Gleixner tglx@linutronix.de Signed-off-by: Patrick Roy patrick.roy@linux.dev Signed-off-by: Nikita Kalyazin kalyazin@amazon.com --- arch/x86/include/asm/tlbflush.h | 3 ++- arch/x86/mm/tlb.c | 1 + 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 00daedfefc1b..6f57f7eb621b 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -317,7 +317,6 @@ extern void flush_tlb_all(void); extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, unsigned long end, unsigned int stride_shift, bool freed_tables); -extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a) { @@ -483,6 +482,8 @@ static inline void cpu_tlbstate_update_lam(unsigned long lam, u64 untag_mask) #endif #endif /* !MODULE */
+extern void flush_tlb_kernel_range(unsigned long start, unsigned long end); + static inline void __native_tlb_flush_global(unsigned long cr4) { native_write_cr4(cr4 ^ X86_CR4_PGE); diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 5d221709353e..cce591d26e4c 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -1561,6 +1561,7 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end)
put_flush_tlb_info(); } +EXPORT_SYMBOL_FOR_MODULES(flush_tlb_kernel_range, "kvm");
/* * This can be used from process context to figure out what the value of