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From:   Marc Zyngier <maz@kernel.org>
To:     linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     will@kernel.org, qperret@google.com, dbrazdil@google.com,
        Srivatsa Vaddagiri <vatsa@codeaurora.org>,
        Shanker R Donthineni <sdonthineni@nvidia.com>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        kernel-team@android.com
Subject: [PATCH 03/16] KVM: arm64: Turn kvm_pgtable_stage2_set_owner into kvm_pgtable_stage2_annotate
Date:   Thu, 15 Jul 2021 17:31:46 +0100
Message-Id: <20210715163159.1480168-4-maz@kernel.org>
In-Reply-To: <20210715163159.1480168-1-maz@kernel.org>
References: <20210715163159.1480168-1-maz@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
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kvm_pgtable_stage2_set_owner() could be generalised into a way
to store up to 63 bits in the page tables, as long as we don't
set bit 0.

Let's just do that.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/kvm_pgtable.h  | 12 +++++++-----
 arch/arm64/kvm/hyp/nvhe/mem_protect.c | 14 ++++++++++++--
 arch/arm64/kvm/hyp/pgtable.c          | 20 ++++++--------------
 3 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index f004c0115d89..9579e8c2793b 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -274,14 +274,16 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
 			   void *mc);
 
 /**
- * kvm_pgtable_stage2_set_owner() - Unmap and annotate pages in the IPA space to
- *				    track ownership.
+ * kvm_pgtable_stage2_annotate() - Unmap and annotate pages in the IPA space
+ *				   to track ownership (and more).
  * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
  * @addr:	Base intermediate physical address to annotate.
  * @size:	Size of the annotated range.
  * @mc:		Cache of pre-allocated and zeroed memory from which to allocate
  *		page-table pages.
- * @owner_id:	Unique identifier for the owner of the page.
+ * @annotation:	A 63 bit value that will be stored in the page tables.
+ *		@annotation[0] must be 0, and @annotation[63:1] is stored
+ *		in the page tables. @annotation as a whole must not be 0.
  *
  * By default, all page-tables are owned by identifier 0. This function can be
  * used to mark portions of the IPA space as owned by other entities. When a
@@ -290,8 +292,8 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
  *
  * Return: 0 on success, negative error code on failure.
  */
-int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
-				 void *mc, u8 owner_id);
+int kvm_pgtable_stage2_annotate(struct kvm_pgtable *pgt, u64 addr, u64 size,
+				void *mc, kvm_pte_t annotation);
 
 /**
  * kvm_pgtable_stage2_unmap() - Remove a mapping from a guest stage-2 page-table.
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index d938ce95d3bd..ffe482c3b818 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -245,6 +245,15 @@ static int host_stage2_idmap(u64 addr)
 	return ret;
 }
 
+#define KVM_INVALID_PTE_OWNER_MASK	GENMASK(63, 56)
+#define KVM_MAX_OWNER_ID		1
+
+static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id)
+{
+	BUG_ON(owner_id > KVM_MAX_OWNER_ID);
+	return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id);
+}
+
 int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end)
 {
 	int ret;
@@ -257,8 +266,9 @@ int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end)
 		return -EINVAL;
 
 	hyp_spin_lock(&host_kvm.lock);
-	ret = kvm_pgtable_stage2_set_owner(&host_kvm.pgt, start, end - start,
-					   &host_s2_pool, pkvm_hyp_id);
+	ret = kvm_pgtable_stage2_annotate(&host_kvm.pgt, start, end - start,
+					  &host_s2_pool,
+					  kvm_init_invalid_leaf_owner(pkvm_hyp_id));
 	hyp_spin_unlock(&host_kvm.lock);
 
 	return ret != -EAGAIN ? ret : 0;
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index a5874ebd0354..a065f6d960af 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -50,9 +50,6 @@
 
 #define KVM_PTE_LEAF_ATTR_S2_IGNORED	GENMASK(58, 55)
 
-#define KVM_INVALID_PTE_OWNER_MASK	GENMASK(63, 56)
-#define KVM_MAX_OWNER_ID		1
-
 struct kvm_pgtable_walk_data {
 	struct kvm_pgtable		*pgt;
 	struct kvm_pgtable_walker	*walker;
@@ -206,11 +203,6 @@ static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, u32 level)
 	return pte;
 }
 
-static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id)
-{
-	return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id);
-}
-
 static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data, u64 addr,
 				  u32 level, kvm_pte_t *ptep,
 				  enum kvm_pgtable_walk_flags flag)
@@ -466,7 +458,7 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
 struct stage2_map_data {
 	u64				phys;
 	kvm_pte_t			attr;
-	u8				owner_id;
+	u64				annotation;
 
 	kvm_pte_t			*anchor;
 	kvm_pte_t			*childp;
@@ -603,7 +595,7 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
 	if (kvm_phys_is_valid(phys))
 		new = kvm_init_valid_leaf_pte(phys, data->attr, level);
 	else
-		new = kvm_init_invalid_leaf_owner(data->owner_id);
+		new = data->annotation;
 
 	if (stage2_pte_is_counted(old)) {
 		/*
@@ -796,8 +788,8 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
 	return ret;
 }
 
-int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
-				 void *mc, u8 owner_id)
+int kvm_pgtable_stage2_annotate(struct kvm_pgtable *pgt, u64 addr, u64 size,
+				void *mc, kvm_pte_t annotation)
 {
 	int ret;
 	struct stage2_map_data map_data = {
@@ -805,7 +797,7 @@ int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
 		.mmu		= pgt->mmu,
 		.memcache	= mc,
 		.mm_ops		= pgt->mm_ops,
-		.owner_id	= owner_id,
+		.annotation	= annotation,
 	};
 	struct kvm_pgtable_walker walker = {
 		.cb		= stage2_map_walker,
@@ -815,7 +807,7 @@ int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
 		.arg		= &map_data,
 	};
 
-	if (owner_id > KVM_MAX_OWNER_ID)
+	if (!annotation || (annotation & PTE_VALID))
 		return -EINVAL;
 
 	ret = kvm_pgtable_walk(pgt, addr, size, &walker);
-- 
2.30.2