Re: [PATCH v4 27/30] x86/tlb: Make __flush_tlb_local() noinstr-compliant

Sean Christopherson
2025-01-14T21:24:23Z

On Tue, Jan 14, 2025, Valentin Schneider wrote:
> Later patches will require issuing a __flush_tlb_all() from noinstr code.
> This requires making both __flush_tlb_local() and __flush_tlb_global()
> noinstr-compliant.
>
> For __flush_tlb_local(), xen_flush_tlb() has already been made noinstr, so
> it's just native_flush_tlb_global(), and simply __always_inline'ing
> invalidate_user_asid() gets us there
>
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---

...

> @@ -1206,7 +1206,7 @@ STATIC_NOPV noinstr void native_flush_tlb_global(void)
> /*
> * Flush the entire current user mapping
> */
> -STATIC_NOPV void native_flush_tlb_local(void)
> +STATIC_NOPV noinstr void native_flush_tlb_local(void)

native_write_cr3() and __native_read_cr3() need to be __always_inline.

vmlinux.o: warning: objtool: native_flush_tlb_local+0x8: call to __native_read_cr3() leaves .noinstr.text section