[RFC 16/33] KVM: x86/mmu: Expose R/W/X flags during memory fault exits

[Nicolas Saenz Julienne]

Include the fault's read, write and execute status when exiting to
user-space.

Signed-off-by: Nicolas Saenz Julienne <nsa...@amazon.com>
---
 arch/x86/kvm/mmu/mmu.c   | 4 ++--
 include/linux/kvm_host.h | 9 +++++++--
 include/uapi/linux/kvm.h | 6 ++++++
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 4e02d506cc25..feca077c0210 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4300,8 +4300,8 @@ static inline u8 kvm_max_level_for_order(int order)
 static void kvm_mmu_prepare_memory_fault_exit(struct kvm_vcpu *vcpu,
                                              struct kvm_page_fault *fault)
 {
-       kvm_prepare_memory_fault_exit(vcpu, fault->gfn << PAGE_SHIFT,
-                                     PAGE_SIZE, fault->write, fault->exec,
+       kvm_prepare_memory_fault_exit(vcpu, fault->gfn << PAGE_SHIFT, PAGE_SIZE,
+                                     fault->write, fault->exec, fault->user,
                                      fault->is_private);
 }
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 71e1e8cf8936..631fd532c97a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2367,14 +2367,19 @@ static inline void kvm_account_pgtable_pages(void 
*virt, int nr)
 static inline void kvm_prepare_memory_fault_exit(struct kvm_vcpu *vcpu,
                                                 gpa_t gpa, gpa_t size,
                                                 bool is_write, bool is_exec,
-                                                bool is_private)
+                                                bool is_read, bool is_private)
 {
        vcpu->run->exit_reason = KVM_EXIT_MEMORY_FAULT;
        vcpu->run->memory_fault.gpa = gpa;
        vcpu->run->memory_fault.size = size;
 
-       /* RWX flags are not (yet) defined or communicated to userspace. */
        vcpu->run->memory_fault.flags = 0;
+       if (is_read)
+               vcpu->run->memory_fault.flags |= KVM_MEMORY_EXIT_FLAG_READ;
+       if (is_write)
+               vcpu->run->memory_fault.flags |= KVM_MEMORY_EXIT_FLAG_WRITE;
+       if (is_exec)
+               vcpu->run->memory_fault.flags |= KVM_MEMORY_EXIT_FLAG_EXECUTE;
        if (is_private)
                vcpu->run->memory_fault.flags |= KVM_MEMORY_EXIT_FLAG_PRIVATE;
 }
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 03f5c08fd7aa..0ddffb8b0c99 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -533,7 +533,13 @@ struct kvm_run {
                } notify;
                /* KVM_EXIT_MEMORY_FAULT */
                struct {
+#define KVM_MEMORY_EXIT_FLAG_READ      (1ULL << 0)
+#define KVM_MEMORY_EXIT_FLAG_WRITE     (1ULL << 1)
+#define KVM_MEMORY_EXIT_FLAG_EXECUTE   (1ULL << 2)
 #define KVM_MEMORY_EXIT_FLAG_PRIVATE   (1ULL << 3)
+#define KVM_MEMORY_EXIT_NO_ACCESS                            \
+       (KVM_MEMORY_EXIT_FLAG_NR | KVM_MEMORY_EXIT_FLAG_NW | \
+        KVM_MEMORY_EXIT_FLAG_NX)
                        __u64 flags;
                        __u64 gpa;
                        __u64 size;
-- 
2.40.1