diff mbox series

[v5,1/6] KVM: arm64: Introduce KVM_PGTABLE_S2_GUEST stage-2 flag

Message ID 20210415115032.35760-2-wangyanan55@huawei.com (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: Improve efficiency of stage2 page table | expand

Commit Message

Yanan Wang April 15, 2021, 11:50 a.m. UTC 
The stage-2 page table code in pgtable.c now is generally used for
guest stage-2 and host stage-2. There may be some different issues
between guest S2 page-table and host S2 page-table that we should
consider, e.g., whether CMOs are needed when creating a new mapping.

So introduce the KVM_PGTABLE_S2_GUEST flag to determine if we are
doing something about guest stage-2. This flag will be used in a
coming patch, in which we will move CMOs for guest to pgtable.c.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
---
 arch/arm64/include/asm/kvm_pgtable.h | 38 ++++++++++++++++++----------
 arch/arm64/kvm/mmu.c                 |  3 ++-
 2 files changed, 26 insertions(+), 15 deletions(-)

Comments

Quentin Perret June 2, 2021, 10:43 a.m. UTC | #1 
Hi Yanan,

On Thursday 15 Apr 2021 at 19:50:27 (+0800), Yanan Wang wrote:
> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> index c3674c47d48c..a43cbe697b37 100644
> --- a/arch/arm64/include/asm/kvm_pgtable.h
> +++ b/arch/arm64/include/asm/kvm_pgtable.h
> @@ -61,10 +61,12 @@ struct kvm_pgtable_mm_ops {
>   * @KVM_PGTABLE_S2_NOFWB:	Don't enforce Normal-WB even if the CPUs have
>   *				ARM64_HAS_STAGE2_FWB.
>   * @KVM_PGTABLE_S2_IDMAP:	Only use identity mappings.
> + * @KVM_PGTABLE_S2_GUEST:	Whether the page-tables are guest stage-2.
>   */
>  enum kvm_pgtable_stage2_flags {
>  	KVM_PGTABLE_S2_NOFWB			= BIT(0),
>  	KVM_PGTABLE_S2_IDMAP			= BIT(1),
> +	KVM_PGTABLE_S2_GUEST			= BIT(2),

Assuming that we need this flag (maybe not given Marc's suggestion on
another patch), I'd recommend re-naming it to explain _what_ it does,
rather than _who_ is using it.

That's the principle we followed for e.g. KVM_PGTABLE_S2_IDMAP, so we
should be consistent here as well.

Thanks,
Quentin
Yanan Wang June 3, 2021, 12:36 p.m. UTC | #2 
Hi Quentin,

On 2021/6/2 18:43, Quentin Perret wrote:
> Hi Yanan,
>
> On Thursday 15 Apr 2021 at 19:50:27 (+0800), Yanan Wang wrote:
>> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
>> index c3674c47d48c..a43cbe697b37 100644
>> --- a/arch/arm64/include/asm/kvm_pgtable.h
>> +++ b/arch/arm64/include/asm/kvm_pgtable.h
>> @@ -61,10 +61,12 @@ struct kvm_pgtable_mm_ops {
>>    * @KVM_PGTABLE_S2_NOFWB:	Don't enforce Normal-WB even if the CPUs have
>>    *				ARM64_HAS_STAGE2_FWB.
>>    * @KVM_PGTABLE_S2_IDMAP:	Only use identity mappings.
>> + * @KVM_PGTABLE_S2_GUEST:	Whether the page-tables are guest stage-2.
>>    */
>>   enum kvm_pgtable_stage2_flags {
>>   	KVM_PGTABLE_S2_NOFWB			= BIT(0),
>>   	KVM_PGTABLE_S2_IDMAP			= BIT(1),
>> +	KVM_PGTABLE_S2_GUEST			= BIT(2),
> Assuming that we need this flag (maybe not given Marc's suggestion on
> another patch), I'd recommend re-naming it to explain _what_ it does,
> rather than _who_ is using it.
I agree with this.
> That's the principle we followed for e.g. KVM_PGTABLE_S2_IDMAP, so we
> should be consistent here as well.
But I think maybe we don't need the new flag anymore with Marc's suggestion.
Currently the CMOs right before installation or update of a PTE are 
guest-specific.
So if we also take the new optional callbacks as guest specific, then a 
new flag is
not necessary because we can check whether the callbacks have been 
initialized
to determine if we are managing a guest S2 PTE.

Thanks,
Yanan
> Thanks,
> Quentin
> .
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index c3674c47d48c..a43cbe697b37 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -61,10 +61,12 @@  struct kvm_pgtable_mm_ops {
  * @KVM_PGTABLE_S2_NOFWB:	Don't enforce Normal-WB even if the CPUs have
  *				ARM64_HAS_STAGE2_FWB.
  * @KVM_PGTABLE_S2_IDMAP:	Only use identity mappings.
+ * @KVM_PGTABLE_S2_GUEST:	Whether the page-tables are guest stage-2.
  */
 enum kvm_pgtable_stage2_flags {
 	KVM_PGTABLE_S2_NOFWB			= BIT(0),
 	KVM_PGTABLE_S2_IDMAP			= BIT(1),
+	KVM_PGTABLE_S2_GUEST			= BIT(2),
 };
 
 /**
@@ -221,12 +223,10 @@  int kvm_pgtable_stage2_init_flags(struct kvm_pgtable *pgt, struct kvm_arch *arch
 				  struct kvm_pgtable_mm_ops *mm_ops,
 				  enum kvm_pgtable_stage2_flags flags);
 
-#define kvm_pgtable_stage2_init(pgt, arch, mm_ops) \
-	kvm_pgtable_stage2_init_flags(pgt, arch, mm_ops, 0)
-
 /**
  * kvm_pgtable_stage2_destroy() - Destroy an unused guest stage-2 page-table.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  *
  * The page-table is assumed to be unreachable by any hardware walkers prior
  * to freeing and therefore no TLB invalidation is performed.
@@ -235,7 +235,8 @@  void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt);
 
 /**
  * kvm_pgtable_stage2_map() - Install a mapping in a guest stage-2 page-table.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Intermediate physical address at which to place the mapping.
  * @size:	Size of the mapping.
  * @phys:	Physical address of the memory to map.
@@ -268,7 +269,8 @@  int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
 /**
  * kvm_pgtable_stage2_set_owner() - Unmap and annotate pages in the IPA space to
  *				    track ownership.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @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
@@ -287,7 +289,8 @@  int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
 
 /**
  * kvm_pgtable_stage2_unmap() - Remove a mapping from a guest stage-2 page-table.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Intermediate physical address from which to remove the mapping.
  * @size:	Size of the mapping.
  *
@@ -307,7 +310,8 @@  int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size);
 /**
  * kvm_pgtable_stage2_wrprotect() - Write-protect guest stage-2 address range
  *                                  without TLB invalidation.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Intermediate physical address from which to write-protect,
  * @size:	Size of the range.
  *
@@ -324,7 +328,8 @@  int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size);
 
 /**
  * kvm_pgtable_stage2_mkyoung() - Set the access flag in a page-table entry.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Intermediate physical address to identify the page-table entry.
  *
  * The offset of @addr within a page is ignored.
@@ -338,7 +343,8 @@  kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr);
 
 /**
  * kvm_pgtable_stage2_mkold() - Clear the access flag in a page-table entry.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Intermediate physical address to identify the page-table entry.
  *
  * The offset of @addr within a page is ignored.
@@ -357,7 +363,8 @@  kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr);
 /**
  * kvm_pgtable_stage2_relax_perms() - Relax the permissions enforced by a
  *				      page-table entry.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Intermediate physical address to identify the page-table entry.
  * @prot:	Additional permissions to grant for the mapping.
  *
@@ -376,7 +383,8 @@  int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
 /**
  * kvm_pgtable_stage2_is_young() - Test whether a page-table entry has the
  *				   access flag set.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Intermediate physical address to identify the page-table entry.
  *
  * The offset of @addr within a page is ignored.
@@ -389,7 +397,8 @@  bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr);
  * kvm_pgtable_stage2_flush_range() - Clean and invalidate data cache to Point
  * 				      of Coherency for guest stage-2 address
  *				      range.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Intermediate physical address from which to flush.
  * @size:	Size of the range.
  *
@@ -428,7 +437,8 @@  int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
  * kvm_pgtable_stage2_find_range() - Find a range of Intermediate Physical
  *				     Addresses with compatible permission
  *				     attributes.
- * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
+ * @pgt:	Page-table structure initialised by function
+ *		kvm_pgtable_stage2_init_flags().
  * @addr:	Address that must be covered by the range.
  * @prot:	Protection attributes that the range must be compatible with.
  * @range:	Range structure used to limit the search space at call time and
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index cd4d51ae3d4a..2cfcfc5f4e4e 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -457,7 +457,8 @@  int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu)
 	if (!pgt)
 		return -ENOMEM;
 
-	err = kvm_pgtable_stage2_init(pgt, &kvm->arch, &kvm_s2_mm_ops);
+	err = kvm_pgtable_stage2_init_flags(pgt, &kvm->arch, &kvm_s2_mm_ops,
+					    KVM_PGTABLE_S2_GUEST);
 	if (err)
 		goto out_free_pgtable;