| Message ID | 20240819131924.372366-16-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: Support for running as a guest in Arm CCA | expand |
On Mon, Aug 19, 2024 at 02:19:20PM +0100, Steven Price wrote: > When __change_memory_common() is purely setting the valid bit on a PTE > (e.g. via the set_memory_valid() call) there is no need for a TLBI as > either the entry isn't changing (the valid bit was already set) or the > entry was invalid and so should not have been cached in the TLB. > > Signed-off-by: Steven Price <steven.price@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 0e270a1c51e6..547a9e0b46c2 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -60,7 +60,13 @@ static int __change_memory_common(unsigned long start, unsigned long size, ret = apply_to_page_range(&init_mm, start, size, change_page_range, &data); - flush_tlb_kernel_range(start, start + size); + /* + * If the memory is being made valid without changing any other bits + * then a TLBI isn't required as a non-valid entry cannot be cached in + * the TLB. + */ + if (pgprot_val(set_mask) != PTE_VALID || pgprot_val(clear_mask)) + flush_tlb_kernel_range(start, start + size); return ret; }
When __change_memory_common() is purely setting the valid bit on a PTE (e.g. via the set_memory_valid() call) there is no need for a TLBI as either the entry isn't changing (the valid bit was already set) or the entry was invalid and so should not have been cached in the TLB. Signed-off-by: Steven Price <steven.price@arm.com> --- v4: New patch --- arch/arm64/mm/pageattr.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)