[PATCH v4 4/7] KVM: x86: Move nested CPU dirty logging logic to common code

[Nikunj A Dadhania <nikunj@amd.com>]

From: Kai Huang <kai.huang@intel.com>

Move nested PML dirty logging update logic from VMX-specific code to common
x86 infrastructure. Both VMX and SVM share identical logic: defer CPU dirty
logging updates when running in L2, then process pending updates when
exiting to L1.

No functional change.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Co-developed-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
 arch/x86/include/asm/kvm_host.h |  3 ++-
 arch/x86/kvm/kvm_cache_regs.h   |  7 +++++++
 arch/x86/kvm/vmx/main.c         |  4 ++--
 arch/x86/kvm/vmx/nested.c       |  5 -----
 arch/x86/kvm/vmx/vmx.c          | 23 ++++-------------------
 arch/x86/kvm/vmx/vmx.h          |  3 +--
 arch/x86/kvm/vmx/x86_ops.h      |  2 +-
 arch/x86/kvm/x86.c              | 22 +++++++++++++++++++++-
 8 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 73b16cecc06d..ca5def4f3585 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -862,6 +862,7 @@ struct kvm_vcpu_arch {
 	struct kvm_mmu_memory_cache mmu_external_spt_cache;
 
 	struct page *pml_page;
+	bool update_cpu_dirty_logging_pending;
 
 	/*
 	 * QEMU userspace and the guest each have their own FPU state.
@@ -1884,7 +1885,7 @@ struct kvm_x86_ops {
 			       struct x86_exception *exception);
 	void (*handle_exit_irqoff)(struct kvm_vcpu *vcpu);
 
-	void (*update_cpu_dirty_logging)(struct kvm_vcpu *vcpu);
+	void (*update_cpu_dirty_logging)(struct kvm_vcpu *vcpu, bool enable);
 
 	const struct kvm_x86_nested_ops *nested_ops;
 
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index 8ddb01191d6f..0c4a832a9dab 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -238,6 +238,13 @@ static inline void leave_guest_mode(struct kvm_vcpu *vcpu)
 		kvm_make_request(KVM_REQ_LOAD_EOI_EXITMAP, vcpu);
 	}
 
+	/* Also see kvm_vcpu_update_cpu_dirty_logging() */
+	if (vcpu->arch.update_cpu_dirty_logging_pending) {
+		vcpu->arch.update_cpu_dirty_logging_pending = false;
+		kvm_x86_call(update_cpu_dirty_logging)(vcpu,
+				atomic_read(&vcpu->kvm->nr_memslots_dirty_logging));
+	}
+
 	vcpu->stat.guest_mode = 0;
 }
 
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 0eb2773b2ae2..6fb97f6ce48e 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -103,7 +103,7 @@ static void vt_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	vmx_vcpu_load(vcpu, cpu);
 }
 
-static void vt_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)
+static void vt_update_cpu_dirty_logging(struct kvm_vcpu *vcpu, bool enable)
 {
 	/*
 	 * Basic TDX does not support feature PML. KVM does not enable PML in
@@ -112,7 +112,7 @@ static void vt_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)
 	if (WARN_ON_ONCE(is_td_vcpu(vcpu)))
 		return;
 
-	vmx_update_cpu_dirty_logging(vcpu);
+	vmx_update_cpu_dirty_logging(vcpu, enable);
 }
 
 static void vt_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 76271962cb70..0093fc389eae 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5202,11 +5202,6 @@ void __nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 vm_exit_reason,
 		vmx_set_virtual_apic_mode(vcpu);
 	}
 
-	if (vmx->nested.update_vmcs01_cpu_dirty_logging) {
-		vmx->nested.update_vmcs01_cpu_dirty_logging = false;
-		vmx_update_cpu_dirty_logging(vcpu);
-	}
-
 	nested_put_vmcs12_pages(vcpu);
 
 	if (vmx->nested.reload_vmcs01_apic_access_page) {
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 81216deb3959..ede5aaf24278 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -8194,27 +8194,12 @@ void vmx_cancel_hv_timer(struct kvm_vcpu *vcpu)
 }
 #endif
 
-void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)
+void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu, bool enable)
 {
-	struct vcpu_vmx *vmx = to_vmx(vcpu);
-
-	if (WARN_ON_ONCE(!enable_pml))
-		return;
-
-	if (is_guest_mode(vcpu)) {
-		vmx->nested.update_vmcs01_cpu_dirty_logging = true;
-		return;
-	}
-
-	/*
-	 * Note, nr_memslots_dirty_logging can be changed concurrent with this
-	 * code, but in that case another update request will be made and so
-	 * the guest will never run with a stale PML value.
-	 */
-	if (atomic_read(&vcpu->kvm->nr_memslots_dirty_logging))
-		secondary_exec_controls_setbit(vmx, SECONDARY_EXEC_ENABLE_PML);
+	if (enable)
+		secondary_exec_controls_setbit(to_vmx(vcpu), SECONDARY_EXEC_ENABLE_PML);
 	else
-		secondary_exec_controls_clearbit(vmx, SECONDARY_EXEC_ENABLE_PML);
+		secondary_exec_controls_clearbit(to_vmx(vcpu), SECONDARY_EXEC_ENABLE_PML);
 }
 
 void vmx_setup_mce(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index d2dd63194ee2..22bf8860add4 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -133,7 +133,6 @@ struct nested_vmx {
 
 	bool change_vmcs01_virtual_apic_mode;
 	bool reload_vmcs01_apic_access_page;
-	bool update_vmcs01_cpu_dirty_logging;
 	bool update_vmcs01_apicv_status;
 	bool update_vmcs01_hwapic_isr;
 
@@ -401,7 +400,7 @@ u64 vmx_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu);
 
 gva_t vmx_get_untagged_addr(struct kvm_vcpu *vcpu, gva_t gva, unsigned int flags);
 
-void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu);
+void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu, bool enable);
 
 u64 vmx_get_supported_debugctl(struct kvm_vcpu *vcpu, bool host_initiated);
 bool vmx_is_valid_debugctl(struct kvm_vcpu *vcpu, u64 data, bool host_initiated);
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 9697368d65b3..1ae01fa592cd 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -113,7 +113,7 @@ u64 vmx_get_l2_tsc_offset(struct kvm_vcpu *vcpu);
 u64 vmx_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu);
 void vmx_write_tsc_offset(struct kvm_vcpu *vcpu);
 void vmx_write_tsc_multiplier(struct kvm_vcpu *vcpu);
-void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu);
+void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu, bool enable);
 #ifdef CONFIG_X86_64
 int vmx_set_hv_timer(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc,
 		     bool *expired);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2b23d7721444..42479fcda688 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -149,6 +149,7 @@ struct kvm_x86_ops kvm_x86_ops __read_mostly;
 #include <asm/kvm-x86-ops.h>
 EXPORT_STATIC_CALL_GPL(kvm_x86_get_cs_db_l_bits);
 EXPORT_STATIC_CALL_GPL(kvm_x86_cache_reg);
+EXPORT_STATIC_CALL_GPL(kvm_x86_update_cpu_dirty_logging);
 
 static bool __read_mostly ignore_msrs = 0;
 module_param(ignore_msrs, bool, 0644);
@@ -11055,6 +11056,25 @@ static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
 	kvm_x86_call(set_apic_access_page_addr)(vcpu);
 }
 
+static void kvm_vcpu_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)
+{
+	if (WARN_ON_ONCE(!enable_pml))
+		return;
+
+	if (is_guest_mode(vcpu)) {
+		vcpu->arch.update_cpu_dirty_logging_pending = true;
+		return;
+	}
+
+	/*
+	 * Note, nr_memslots_dirty_logging can be changed concurrently with this
+	 * code, but in that case another update request will be made and so the
+	 * guest will never run with a stale PML value.
+	 */
+	kvm_x86_call(update_cpu_dirty_logging)(vcpu,
+			atomic_read(&vcpu->kvm->nr_memslots_dirty_logging));
+}
+
 /*
  * Called within kvm->srcu read side.
  * Returns 1 to let vcpu_run() continue the guest execution loop without
@@ -11221,7 +11241,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 			kvm_x86_call(recalc_intercepts)(vcpu);
 
 		if (kvm_check_request(KVM_REQ_UPDATE_CPU_DIRTY_LOGGING, vcpu))
-			kvm_x86_call(update_cpu_dirty_logging)(vcpu);
+			kvm_vcpu_update_cpu_dirty_logging(vcpu);
 
 		if (kvm_check_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, vcpu)) {
 			kvm_vcpu_reset(vcpu, true);
-- 
2.48.1