diff mbox series

[v8,02/12] KVM: arm64: Add KVM_PGTABLE_WALK flags for skipping CMOs and BBM TLBIs

Message ID 20230426172330.1439644-3-ricarkol@google.com (mailing list archive)
State New, archived
Headers show
Series Implement Eager Page Splitting for ARM | expand

Commit Message

Ricardo Koller April 26, 2023, 5:23 p.m. UTC 
Add two flags to kvm_pgtable_visit_ctx, KVM_PGTABLE_WALK_SKIP_BBM_TLBI
and KVM_PGTABLE_WALK_SKIP_CMO, to indicate that the walk should not
perform TLB invalidations (TLBIs) in break-before-make (BBM) nor cache
maintenance operations (CMO). This will be used by a future commit to
create unlinked tables not accessible to the HW page-table walker.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
---
 arch/arm64/include/asm/kvm_pgtable.h |  8 ++++++
 arch/arm64/kvm/hyp/pgtable.c         | 37 +++++++++++++++++++---------
 2 files changed, 34 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 965fddcd53b8b..7bbd77e9b7b47 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -195,6 +195,12 @@  typedef bool (*kvm_pgtable_force_pte_cb_t)(u64 addr, u64 end,
  *					with other software walkers.
  * @KVM_PGTABLE_WALK_HANDLE_FAULT:	Indicates the page-table walk was
  *					invoked from a fault handler.
+ * @KVM_PGTABLE_WALK_SKIP_BBM_TLBI:	Visit and update table entries
+ *					without Break-before-make's
+ *					TLB invalidation.
+ * @KVM_PGTABLE_WALK_SKIP_CMO:		Visit and update table entries
+ *					without Cache maintenance
+ *					operations required.
  */
 enum kvm_pgtable_walk_flags {
 	KVM_PGTABLE_WALK_LEAF			= BIT(0),
@@ -202,6 +208,8 @@  enum kvm_pgtable_walk_flags {
 	KVM_PGTABLE_WALK_TABLE_POST		= BIT(2),
 	KVM_PGTABLE_WALK_SHARED			= BIT(3),
 	KVM_PGTABLE_WALK_HANDLE_FAULT		= BIT(4),
+	KVM_PGTABLE_WALK_SKIP_BBM_TLBI		= BIT(5),
+	KVM_PGTABLE_WALK_SKIP_CMO		= BIT(6),
 };
 
 struct kvm_pgtable_visit_ctx {
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 1dfbc4848ae52..64c96f9116171 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -63,6 +63,16 @@  struct kvm_pgtable_walk_data {
 	const u64			end;
 };
 
+static bool kvm_pgtable_walk_skip_bbm_tlbi(const struct kvm_pgtable_visit_ctx *ctx)
+{
+	return unlikely(ctx->flags & KVM_PGTABLE_WALK_SKIP_BBM_TLBI);
+}
+
+static bool kvm_pgtable_walk_skip_cmo(const struct kvm_pgtable_visit_ctx *ctx)
+{
+	return unlikely(ctx->flags & KVM_PGTABLE_WALK_SKIP_CMO);
+}
+
 static bool kvm_phys_is_valid(u64 phys)
 {
 	return phys < BIT(id_aa64mmfr0_parange_to_phys_shift(ID_AA64MMFR0_EL1_PARANGE_MAX));
@@ -743,14 +753,17 @@  static bool stage2_try_break_pte(const struct kvm_pgtable_visit_ctx *ctx,
 	if (!stage2_try_set_pte(ctx, KVM_INVALID_PTE_LOCKED))
 		return false;
 
-	/*
-	 * Perform the appropriate TLB invalidation based on the evicted pte
-	 * value (if any).
-	 */
-	if (kvm_pte_table(ctx->old, ctx->level))
-		kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
-	else if (kvm_pte_valid(ctx->old))
-		kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr, ctx->level);
+	if (!kvm_pgtable_walk_skip_bbm_tlbi(ctx)) {
+		/*
+		 * Perform the appropriate TLB invalidation based on the
+		 * evicted pte value (if any).
+		 */
+		if (kvm_pte_table(ctx->old, ctx->level))
+			kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
+		else if (kvm_pte_valid(ctx->old))
+			kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu,
+				     ctx->addr, ctx->level);
+	}
 
 	if (stage2_pte_is_counted(ctx->old))
 		mm_ops->put_page(ctx->ptep);
@@ -857,11 +870,13 @@  static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
 		return -EAGAIN;
 
 	/* Perform CMOs before installation of the guest stage-2 PTE */
-	if (mm_ops->dcache_clean_inval_poc && stage2_pte_cacheable(pgt, new))
+	if (!kvm_pgtable_walk_skip_cmo(ctx) && mm_ops->dcache_clean_inval_poc &&
+	    stage2_pte_cacheable(pgt, new))
 		mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops),
-						granule);
+					       granule);
 
-	if (mm_ops->icache_inval_pou && stage2_pte_executable(new))
+	if (!kvm_pgtable_walk_skip_cmo(ctx) && mm_ops->icache_inval_pou &&
+	    stage2_pte_executable(new))
 		mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule);
 
 	stage2_make_pte(ctx, new);