Hi Ricardo,
On 3/2/23 05:09, Ricardo Koller wrote:
Add two flags to kvm_pgtable_visit_ctx, KVM_PGTABLE_WALK_SKIP_BBM and
KVM_PGTABLE_WALK_SKIP_CMO, to indicate that the walk should not
perform break-before-make (BBM) nor cache maintenance operations
(CMO). This will by a future commit to create unlinked tables not
accessible to the HW page-table walker. This is safe as these removed
/s/removed/unlinked
And how about switch the sequence of the Patch 1 and 2, I think first
Rename the removed to unlinked, and then use the unlinked make more sense.
tables are not visible to the HW page-table walker.
But anyway, this patch LGTM.
Reviewed-by: Shaoqin Huang <shahuang@xxxxxxxxxx>
Thanks,
Shaoqin
Signed-off-by: Ricardo Koller <ricarkol@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_pgtable.h | 18 ++++++++++++++++++
arch/arm64/kvm/hyp/pgtable.c | 27 ++++++++++++++++-----------
2 files changed, 34 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 63f81b27a4e3..252b651f743d 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -188,12 +188,20 @@ typedef bool (*kvm_pgtable_force_pte_cb_t)(u64 addr, u64 end,
* children.
* @KVM_PGTABLE_WALK_SHARED: Indicates the page-tables may be shared
* with other software walkers.
+ * @KVM_PGTABLE_WALK_SKIP_BBM: Visit and update table entries
+ * without Break-before-make
+ * requirements.
+ * @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),
KVM_PGTABLE_WALK_TABLE_PRE = BIT(1),
KVM_PGTABLE_WALK_TABLE_POST = BIT(2),
KVM_PGTABLE_WALK_SHARED = BIT(3),
+ KVM_PGTABLE_WALK_SKIP_BBM = BIT(4),
+ KVM_PGTABLE_WALK_SKIP_CMO = BIT(5),
};
struct kvm_pgtable_visit_ctx {
@@ -215,6 +223,16 @@ static inline bool kvm_pgtable_walk_shared(const struct kvm_pgtable_visit_ctx *c
return ctx->flags & KVM_PGTABLE_WALK_SHARED;
}
+static inline bool kvm_pgtable_walk_skip_bbm(const struct kvm_pgtable_visit_ctx *ctx)
+{
+ return ctx->flags & KVM_PGTABLE_WALK_SKIP_BBM;
+}
+
+static inline bool kvm_pgtable_walk_skip_cmo(const struct kvm_pgtable_visit_ctx *ctx)
+{
+ return ctx->flags & KVM_PGTABLE_WALK_SKIP_CMO;
+}
+
/**
* struct kvm_pgtable_walker - Hook into a page-table walk.
* @cb: Callback function to invoke during the walk.
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index b11cf2c618a6..e093e222daf3 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -717,14 +717,17 @@ 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(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);
@@ -808,11 +811,13 @@ 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);
--
Shaoqin
