[v9,23/84] KVM: x86: add .fault_gla()

Commit Message

Adalbert Lazăr July 21, 2020, 9:08 p.m. UTC

From: Mihai Donțu <[e-mail]>

This function is needed for kvmi_update_ad_flags()
and kvm_page_track_emulation_failure().

kvmi_update_ad_flags() uses the the existing guest page table walk code
to update the A/D bits and return to guest (on SPT page faults caused
by guest page table walks when the introspection tool write-protects
the guest page tables).

kvm_page_track_emulation_failure() calls the page tracking code, which
will be changed with a following patch to receive the GVA in addition to
the GPA. Both might be needed by the introspection tool.

Signed-off-by: Mihai Donțu <[e-mail]>
Co-developed-by: Nicușor Cîțu <[e-mail]>
Signed-off-by: Nicușor Cîțu <[e-mail]>
Signed-off-by: Adalbert Lazăr <[e-mail]>
---
 arch/x86/include/asm/kvm_host.h | 2 ++
 arch/x86/include/asm/vmx.h      | 2 ++
 arch/x86/kvm/svm/svm.c          | 9 +++++++++
 arch/x86/kvm/vmx/vmx.c          | 9 +++++++++
 4 files changed, 22 insertions(+)

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2530af4420cf..ccf2804f46b9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1290,6 +1290,8 @@  struct kvm_x86_ops {
 	int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu);
 
 	void (*migrate_timers)(struct kvm_vcpu *vcpu);
+
+	u64 (*fault_gla)(struct kvm_vcpu *vcpu);
 };
 
 struct kvm_x86_nested_ops {
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index cd7de4b401fe..04487eb38b5c 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -543,6 +543,7 @@  enum vm_entry_failure_code {
 #define EPT_VIOLATION_READABLE_BIT	3
 #define EPT_VIOLATION_WRITABLE_BIT	4
 #define EPT_VIOLATION_EXECUTABLE_BIT	5
+#define EPT_VIOLATION_GLA_VALID_BIT	7
 #define EPT_VIOLATION_GVA_TRANSLATED_BIT 8
 #define EPT_VIOLATION_ACC_READ		(1 << EPT_VIOLATION_ACC_READ_BIT)
 #define EPT_VIOLATION_ACC_WRITE		(1 << EPT_VIOLATION_ACC_WRITE_BIT)
@@ -550,6 +551,7 @@  enum vm_entry_failure_code {
 #define EPT_VIOLATION_READABLE		(1 << EPT_VIOLATION_READABLE_BIT)
 #define EPT_VIOLATION_WRITABLE		(1 << EPT_VIOLATION_WRITABLE_BIT)
 #define EPT_VIOLATION_EXECUTABLE	(1 << EPT_VIOLATION_EXECUTABLE_BIT)
+#define EPT_VIOLATION_GLA_VALID		(1 << EPT_VIOLATION_GLA_VALID_BIT)
 #define EPT_VIOLATION_GVA_TRANSLATED	(1 << EPT_VIOLATION_GVA_TRANSLATED_BIT)
 
 /*
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 1ec88ff241ab..86b670ff33dd 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4082,6 +4082,13 @@  static int svm_vm_init(struct kvm *kvm)
 	return 0;
 }
 
+static u64 svm_fault_gla(struct kvm_vcpu *vcpu)
+{
+	const struct vcpu_svm *svm = to_svm(vcpu);
+
+	return svm->vcpu.arch.cr2 ? svm->vcpu.arch.cr2 : ~0ull;
+}
+
 static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.hardware_unsetup = svm_hardware_teardown,
 	.hardware_enable = svm_hardware_enable,
@@ -4208,6 +4215,8 @@  static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.need_emulation_on_page_fault = svm_need_emulation_on_page_fault,
 
 	.apic_init_signal_blocked = svm_apic_init_signal_blocked,
+
+	.fault_gla = svm_fault_gla,
 };
 
 static struct kvm_x86_init_ops svm_init_ops __initdata = {
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 6554c2278176..a04c46cde5b3 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7902,6 +7902,13 @@  static bool vmx_check_apicv_inhibit_reasons(ulong bit)
 	return supported & BIT(bit);
 }
 
+static u64 vmx_fault_gla(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.exit_qualification & EPT_VIOLATION_GLA_VALID)
+		return vmcs_readl(GUEST_LINEAR_ADDRESS);
+	return ~0ull;
+}
+
 static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.hardware_unsetup = hardware_unsetup,
 
@@ -8038,6 +8045,8 @@  static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.need_emulation_on_page_fault = vmx_need_emulation_on_page_fault,
 	.apic_init_signal_blocked = vmx_apic_init_signal_blocked,
 	.migrate_timers = vmx_migrate_timers,
+
+	.fault_gla = vmx_fault_gla,
 };
 
 static __init int hardware_setup(void)