Currently, during the operations such as a hugepage collapse,
KVM would flush the entire VM's context using 'vmalls12e1is'
TLBI operation. Specifically, if the VM is faulting on many
hugepages (say after dirty-logging), it creates a performance
penalty for the guest whose pages have already been faulted
earlier as they would have to refill their TLBs again.

Instead, leverage kvm_tlb_flush_vmid_range() for table entries.
If the system supports it, only the required range will be
flushed. Else, it'll fallback to the previous mechanism.

Signed-off-by: Raghavendra Rao Ananta <redacted>
Reviewed-by: Gavin Shan <redacted>
---
 arch/arm64/kvm/hyp/pgtable.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 5d14d5d5819a..5ef098af1736 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c

@@ -806,7 +806,8 @@ static bool stage2_try_break_pte(const struct kvm_pgtable_visit_ctx *ctx,
 		 * evicted pte value (if any).
 		 */
 		if (kvm_pte_table(ctx->old, ctx->level))
-			kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
+			kvm_tlb_flush_vmid_range(mmu, ctx->addr,
+						kvm_granule_size(ctx->level));
 		else if (kvm_pte_valid(ctx->old))
 			kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu,
 				     ctx->addr, ctx->level);

-- 
2.41.0.455.g037347b96a-goog


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel