KVM: arm64: Invalidate the table entries upon a range

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 <rananta@google.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230811045127.3308641-14-rananta@google.com

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index fb58a22..1a4af37 100644 (file)
--- 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);