[RFC PATCH 2/6] kvm: x86: Introduce guest private memory address space to memslot

[Chao Peng <chao.p.peng@linux.intel.com>]

Existing memslots functions are extended to pass a bool ‘private’
parameter to indicate whether the operation is on guest private memory
address space or not.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
---
 arch/x86/include/asm/kvm_host.h |  5 +++--
 arch/x86/include/uapi/asm/kvm.h |  4 ++++
 arch/x86/kvm/mmu/mmu.c          |  2 +-
 include/linux/kvm_host.h        | 23 ++++++++++++++++++++---
 virt/kvm/kvm_main.c             |  9 ++++++++-
 5 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 20dfcdd20e81..048089883650 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1741,9 +1741,10 @@ enum {
 #define HF_SMM_INSIDE_NMI_MASK	(1 << 7)
 
 #define __KVM_VCPU_MULTIPLE_ADDRESS_SPACE
-#define KVM_ADDRESS_SPACE_NUM 2
+#define KVM_ADDRESS_SPACE_NUM 3
 
-#define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0)
+#define kvm_arch_vcpu_memslots_id(vcpu, private)	\
+	(((vcpu)->arch.hflags & HF_SMM_MASK) ? 1 : (!!private) << 1)
 #define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm)
 
 asmlinkage void kvm_spurious_fault(void);
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 47bc1a0df5ee..65189cfd3837 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -53,6 +53,10 @@
 /* Architectural interrupt line count. */
 #define KVM_NR_INTERRUPTS 256
 
+#define KVM_DEFAULT_ADDRESS_SPACE	0
+#define KVM_SMM_ADDRESS_SPACE		1
+#define KVM_PRIVATE_ADDRESS_SPACE	2
+
 struct kvm_memory_alias {
 	__u32 slot;  /* this has a different namespace than memory slots */
 	__u32 flags;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 79d4ae465a96..8483c15eac6f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3938,7 +3938,7 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
 		return false;
 	}
 
-	/* Don't expose private memslots to L2. */
+	/* Don't expose KVM's internal memslots to L2. */
 	if (is_guest_mode(vcpu) && !kvm_is_visible_memslot(slot)) {
 		*pfn = KVM_PFN_NOSLOT;
 		*writable = false;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 597841fe3d7a..8e5b197230ed 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -442,7 +442,7 @@ struct kvm_irq_routing_table {
 #define KVM_USER_MEM_SLOTS (KVM_MEM_SLOTS_NUM - KVM_PRIVATE_MEM_SLOTS)
 
 #ifndef __KVM_VCPU_MULTIPLE_ADDRESS_SPACE
-static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu)
+static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu, bool private)
 {
 	return 0;
 }
@@ -699,13 +699,19 @@ static inline struct kvm_memslots *kvm_memslots(struct kvm *kvm)
 	return __kvm_memslots(kvm, 0);
 }
 
-static inline struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu)
+static inline struct kvm_memslots *__kvm_vcpu_memslots(struct kvm_vcpu *vcpu,
+						       bool private)
 {
-	int as_id = kvm_arch_vcpu_memslots_id(vcpu);
+	int as_id = kvm_arch_vcpu_memslots_id(vcpu, private);
 
 	return __kvm_memslots(vcpu->kvm, as_id);
 }
 
+static inline struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu)
+{
+	return __kvm_vcpu_memslots(vcpu, false);
+}
+
 static inline
 struct kvm_memory_slot *id_to_memslot(struct kvm_memslots *slots, int id)
 {
@@ -721,6 +727,15 @@ struct kvm_memory_slot *id_to_memslot(struct kvm_memslots *slots, int id)
 	return slot;
 }
 
+static inline bool memslot_is_private(const struct kvm_memory_slot *slot)
+{
+#ifdef KVM_PRIVATE_ADDRESS_SPACE
+	return slot && slot->as_id == KVM_PRIVATE_ADDRESS_SPACE;
+#else
+	return false;
+#endif
+}
+
 /*
  * KVM_SET_USER_MEMORY_REGION ioctl allows the following operations:
  * - create a new memory slot
@@ -860,6 +875,8 @@ void mark_page_dirty_in_slot(struct kvm *kvm, struct kvm_memory_slot *memslot, g
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn);
 
 struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu);
+struct kvm_memory_slot *__kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu,
+						  gfn_t gfn, bool private);
 struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn);
 kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn);
 kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8815218630dc..fe62df334054 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1721,9 +1721,16 @@ struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(gfn_to_memslot);
 
+struct kvm_memory_slot *__kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu,
+						  gfn_t gfn, bool private)
+{
+	return __gfn_to_memslot(__kvm_vcpu_memslots(vcpu, private), gfn);
+}
+EXPORT_SYMBOL_GPL(__kvm_vcpu_gfn_to_memslot);
+
 struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
-	return __gfn_to_memslot(kvm_vcpu_memslots(vcpu), gfn);
+	return __kvm_vcpu_gfn_to_memslot(vcpu, gfn, false);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_memslot);
 
-- 
2.17.1