x86/mm: Fix flush_tlb_page() on Xen

amluto · Ingo Molnar · commit dbd68d8e84c6 · 2017-04-26T10:02:06.000+02:00
flush_tlb_page() passes a bogus range to flush_tlb_others() and expects the latter to fix it up. native_flush_tlb_others() has the fixup but Xen's version doesn't. Move the fixup to flush_tlb_others(). AFAICS the only real effect is that, without this fix, Xen would flush everything instead of just the one page on remote vCPUs in when flush_tlb_page() was called. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Nadav Amit <namit@vmware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: e7b52ff ("x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range") Link: http://lkml.kernel.org/r/10ed0e4dfea64daef10b87fb85df1746999b4dba.1492844372.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
@@ -263,8 +263,6 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
 {
 	struct flush_tlb_info info;
 
-	if (end == 0)
-		end = start + PAGE_SIZE;
 	info.flush_mm = mm;
 	info.flush_start = start;
 	info.flush_end = end;
@@ -378,7 +376,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long start)
 	}
 
 	if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)
-		flush_tlb_others(mm_cpumask(mm), mm, start, 0UL);
+		flush_tlb_others(mm_cpumask(mm), mm, start, start + PAGE_SIZE);
 
 	preempt_enable();
 }

Original file line number	Diff line number	Diff line change
`@@ -263,8 +263,6 @@ void native_flush_tlb_others(const struct cpumask *cpumask,`
`263`	`263`	`{`
`264`	`264`	`struct flush_tlb_info info;`
`265`	`265`
`266`		`- if (end == 0)`
`267`		`- end = start + PAGE_SIZE;`
`268`	`266`	`info.flush_mm = mm;`
`269`	`267`	`info.flush_start = start;`
`270`	`268`	`info.flush_end = end;`
`@@ -378,7 +376,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long start)`
`378`	`376`	`}`
`379`	`377`
`380`	`378`	`if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)`
`381`		`- flush_tlb_others(mm_cpumask(mm), mm, start, 0UL);`
	`379`	`+ flush_tlb_others(mm_cpumask(mm), mm, start, start + PAGE_SIZE);`
`382`	`380`
`383`	`381`	`preempt_enable();`
`384`	`382`	`}`