diff mbox series

[RFC,21/33] KVM: Pass memory attribute array as a MMU notifier argument

Message ID 20231108111806.92604-22-nsaenz@amazon.com
State New
Headers
Series KVM: x86: hyperv: Introduce VSM support |

Commit Message

Nicolas Saenz Julienne Nov. 8, 2023, 11:17 a.m. UTC 
  Pass the memory attribute array through struct kvm_mmu_notifier_arg and
use it in kvm_arch_post_set_memory_attributes() instead of defaulting on
kvm->mem_attr_array.

Signed-off-by: Nicolas Saenz Julienne <nsaenz@amazon.com>
---
 arch/x86/kvm/mmu/mmu.c   | 8 ++++----
 include/linux/kvm_host.h | 5 ++++-
 virt/kvm/kvm_main.c      | 1 +
 3 files changed, 9 insertions(+), 5 deletions(-)

Comments

Sean Christopherson Nov. 8, 2023, 5:08 p.m. UTC | #1 
On Wed, Nov 08, 2023, Nicolas Saenz Julienne wrote:
> Pass the memory attribute array through struct kvm_mmu_notifier_arg and
> use it in kvm_arch_post_set_memory_attributes() instead of defaulting on
> kvm->mem_attr_array.
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenz@amazon.com>
> ---
>  arch/x86/kvm/mmu/mmu.c   | 8 ++++----
>  include/linux/kvm_host.h | 5 ++++-
>  virt/kvm/kvm_main.c      | 1 +
>  3 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index c0fd3afd6be5..c2bec2be2ba9 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -7311,6 +7311,7 @@ static bool hugepage_has_attrs(struct xarray *mem_attr_array,
>  bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
>  					 struct kvm_gfn_range *range)
>  {
> +	struct xarray *mem_attr_array = range->arg.mem_attr_array;
>  	unsigned long attrs = range->arg.attributes;
>  	struct kvm_memory_slot *slot = range->slot;
>  	int level;
> @@ -7344,8 +7345,8 @@ bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
>  			 * misaligned address regardless of memory attributes.
>  			 */
>  			if (gfn >= slot->base_gfn) {
> -				if (hugepage_has_attrs(&kvm->mem_attr_array,
> -						       slot, gfn, level, attrs))
> +				if (hugepage_has_attrs(mem_attr_array, slot,
> +						       gfn, level, attrs))

This is wildly broken.  The hugepage tracking is per VM, whereas the attributes
here are per-VTL.  I.e. KVM will (dis)allow hugepages based on whatever VTL last
changed its protections.
diff mbox series

Patch

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c0fd3afd6be5..c2bec2be2ba9 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -7311,6 +7311,7 @@  static bool hugepage_has_attrs(struct xarray *mem_attr_array,
 bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
 					 struct kvm_gfn_range *range)
 {
+	struct xarray *mem_attr_array = range->arg.mem_attr_array;
 	unsigned long attrs = range->arg.attributes;
 	struct kvm_memory_slot *slot = range->slot;
 	int level;
@@ -7344,8 +7345,8 @@  bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
 			 * misaligned address regardless of memory attributes.
 			 */
 			if (gfn >= slot->base_gfn) {
-				if (hugepage_has_attrs(&kvm->mem_attr_array,
-						       slot, gfn, level, attrs))
+				if (hugepage_has_attrs(mem_attr_array, slot,
+						       gfn, level, attrs))
 					hugepage_clear_mixed(slot, gfn, level);
 				else
 					hugepage_set_mixed(slot, gfn, level);
@@ -7367,8 +7368,7 @@  bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
 		 */
 		if (gfn < range->end &&
 		    (gfn + nr_pages) <= (slot->base_gfn + slot->npages)) {
-			if (hugepage_has_attrs(&kvm->mem_attr_array, slot, gfn,
-					       level, attrs))
+			if (hugepage_has_attrs(mem_attr_array, slot, gfn, level, attrs))
 				hugepage_clear_mixed(slot, gfn, level);
 			else
 				hugepage_set_mixed(slot, gfn, level);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 32cf05637647..652656444c45 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -256,7 +256,10 @@  int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu);
 #ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
 union kvm_mmu_notifier_arg {
 	pte_t pte;
-	unsigned long attributes;
+	struct {
+		unsigned long attributes;
+		struct xarray *mem_attr_array;
+	};
 };
 
 struct kvm_gfn_range {
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6bb23eaf7aa6..f20dafaedc72 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2569,6 +2569,7 @@  static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 		.start = start,
 		.end = end,
 		.arg.attributes = attributes,
+		.arg.mem_attr_array = &kvm->mem_attr_array,
 		.handler = kvm_arch_post_set_memory_attributes,
 		.on_lock = kvm_mmu_invalidate_end,
 		.may_block = true,