[PATCH 02/16] KVM: VMX: Remove use of struct vcpu_vmx from posted_intr.c

[Binbin Wu]

From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

Unify the layout for vcpu_vmx and vcpu_tdx at the top of the structure
with members needed in posted-intr.c, and introduce a struct vcpu_pi to
have the common part.  Use vcpu_pi instead of vcpu_vmx to enable TDX
compatibility with posted_intr.c.

To minimize the diff size, code conversion such as changing vmx->pi_desc
to vmx->common->pi_desc is avoided.  Instead, compile-time checks are
added to ensure the layout is as expected.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Co-developed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
---
TDX interrupts breakout:
- Renamed from "KVM: TDX: remove use of struct vcpu_vmx from posted_interrupt.c"
  to "KVM: VMX: Remove use of struct vcpu_vmx from posted_intr.c".
- Use vcpu_pi instead vcpu_vmx in pi_wakeup_handler(). (Binbin)
- Update change log.
- Remove functional change from the code refactor patch, move into its
  own separate patch. (Chao)
---
 arch/x86/kvm/vmx/posted_intr.c | 43 +++++++++++++++++++++++++---------
 arch/x86/kvm/vmx/posted_intr.h | 11 +++++++++
 arch/x86/kvm/vmx/tdx.c         |  1 +
 arch/x86/kvm/vmx/tdx.h         | 11 +++++++++
 arch/x86/kvm/vmx/vmx.h         | 14 ++++++-----
 5 files changed, 63 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c
index ec08fa3caf43..8951c773a475 100644
--- a/arch/x86/kvm/vmx/posted_intr.c
+++ b/arch/x86/kvm/vmx/posted_intr.c
@@ -11,6 +11,7 @@
 #include "posted_intr.h"
 #include "trace.h"
 #include "vmx.h"
+#include "tdx.h"
 
 /*
  * Maintain a per-CPU list of vCPUs that need to be awakened by wakeup_handler()
@@ -31,9 +32,29 @@ static DEFINE_PER_CPU(struct list_head, wakeup_vcpus_on_cpu);
  */
 static DEFINE_PER_CPU(raw_spinlock_t, wakeup_vcpus_on_cpu_lock);
 
+/*
+ * The layout of the head of struct vcpu_vmx and struct vcpu_tdx must match with
+ * struct vcpu_pi.
+ */
+static_assert(offsetof(struct vcpu_pi, pi_desc) ==
+	      offsetof(struct vcpu_vmx, pi_desc));
+static_assert(offsetof(struct vcpu_pi, pi_wakeup_list) ==
+	      offsetof(struct vcpu_vmx, pi_wakeup_list));
+#ifdef CONFIG_INTEL_TDX_HOST
+static_assert(offsetof(struct vcpu_pi, pi_desc) ==
+	      offsetof(struct vcpu_tdx, pi_desc));
+static_assert(offsetof(struct vcpu_pi, pi_wakeup_list) ==
+	      offsetof(struct vcpu_tdx, pi_wakeup_list));
+#endif
+
+static inline struct vcpu_pi *vcpu_to_pi(struct kvm_vcpu *vcpu)
+{
+	return (struct vcpu_pi *)vcpu;
+}
+
 static inline struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu *vcpu)
 {
-	return &(to_vmx(vcpu)->pi_desc);
+	return &vcpu_to_pi(vcpu)->pi_desc;
 }
 
 static int pi_try_set_control(struct pi_desc *pi_desc, u64 *pold, u64 new)
@@ -52,8 +73,8 @@ static int pi_try_set_control(struct pi_desc *pi_desc, u64 *pold, u64 new)
 
 void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu)
 {
-	struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
-	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	struct vcpu_pi *vcpu_pi = vcpu_to_pi(vcpu);
+	struct pi_desc *pi_desc = &vcpu_pi->pi_desc;
 	struct pi_desc old, new;
 	unsigned long flags;
 	unsigned int dest;
@@ -90,7 +111,7 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu)
 	 */
 	if (pi_desc->nv == POSTED_INTR_WAKEUP_VECTOR) {
 		raw_spin_lock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu));
-		list_del(&vmx->pi_wakeup_list);
+		list_del(&vcpu_pi->pi_wakeup_list);
 		raw_spin_unlock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu));
 	}
 
@@ -145,15 +166,15 @@ static bool vmx_can_use_vtd_pi(struct kvm *kvm)
  */
 static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu)
 {
-	struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
-	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	struct vcpu_pi *vcpu_pi = vcpu_to_pi(vcpu);
+	struct pi_desc *pi_desc = &vcpu_pi->pi_desc;
 	struct pi_desc old, new;
 	unsigned long flags;
 
 	local_irq_save(flags);
 
 	raw_spin_lock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu));
-	list_add_tail(&vmx->pi_wakeup_list,
+	list_add_tail(&vcpu_pi->pi_wakeup_list,
 		      &per_cpu(wakeup_vcpus_on_cpu, vcpu->cpu));
 	raw_spin_unlock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu));
 
@@ -220,13 +241,13 @@ void pi_wakeup_handler(void)
 	int cpu = smp_processor_id();
 	struct list_head *wakeup_list = &per_cpu(wakeup_vcpus_on_cpu, cpu);
 	raw_spinlock_t *spinlock = &per_cpu(wakeup_vcpus_on_cpu_lock, cpu);
-	struct vcpu_vmx *vmx;
+	struct vcpu_pi *pi;
 
 	raw_spin_lock(spinlock);
-	list_for_each_entry(vmx, wakeup_list, pi_wakeup_list) {
+	list_for_each_entry(pi, wakeup_list, pi_wakeup_list) {
 
-		if (pi_test_on(&vmx->pi_desc))
-			kvm_vcpu_wake_up(&vmx->vcpu);
+		if (pi_test_on(&pi->pi_desc))
+			kvm_vcpu_wake_up(&pi->vcpu);
 	}
 	raw_spin_unlock(spinlock);
 }
diff --git a/arch/x86/kvm/vmx/posted_intr.h b/arch/x86/kvm/vmx/posted_intr.h
index 1715d2ab07be..e579e8c3ad2e 100644
--- a/arch/x86/kvm/vmx/posted_intr.h
+++ b/arch/x86/kvm/vmx/posted_intr.h
@@ -5,6 +5,17 @@
 #include <linux/find.h>
 #include <asm/posted_intr.h>
 
+struct vcpu_pi {
+	struct kvm_vcpu	vcpu;
+
+	/* Posted interrupt descriptor */
+	struct pi_desc pi_desc;
+
+	/* Used if this vCPU is waiting for PI notification wakeup. */
+	struct list_head pi_wakeup_list;
+	/* Until here common layout between vcpu_vmx and vcpu_tdx. */
+};
+
 void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu);
 void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu);
 void pi_wakeup_handler(void);
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 877cf9e1fd65..478da0ebd225 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -723,6 +723,7 @@ int tdx_vcpu_create(struct kvm_vcpu *vcpu)
 
 	fpstate_set_confidential(&vcpu->arch.guest_fpu);
 	vcpu->arch.apic->guest_apic_protected = true;
+	INIT_LIST_HEAD(&tdx->pi_wakeup_list);
 
 	vcpu->arch.efer = EFER_SCE | EFER_LME | EFER_LMA | EFER_NX;
 
diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
index a7dd2b0b5dd7..d6a0fc20ecaa 100644
--- a/arch/x86/kvm/vmx/tdx.h
+++ b/arch/x86/kvm/vmx/tdx.h
@@ -17,6 +17,10 @@ enum kvm_tdx_state {
 	TD_STATE_RUNNABLE,
 };
 
+
+#include "irq.h"
+#include "posted_intr.h"
+
 struct kvm_tdx {
 	struct kvm kvm;
 
@@ -52,6 +56,13 @@ enum tdx_prepare_switch_state {
 struct vcpu_tdx {
 	struct kvm_vcpu	vcpu;
 
+	/* Posted interrupt descriptor */
+	struct pi_desc pi_desc;
+
+	/* Used if this vCPU is waiting for PI notification wakeup. */
+	struct list_head pi_wakeup_list;
+	/* Until here same layout to struct vcpu_pi. */
+
 	unsigned long tdvpr_pa;
 	unsigned long *tdcx_pa;
 
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 37a555c6dfbf..e7f570ca3c19 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -230,6 +230,14 @@ struct nested_vmx {
 
 struct vcpu_vmx {
 	struct kvm_vcpu       vcpu;
+
+	/* Posted interrupt descriptor */
+	struct pi_desc pi_desc;
+
+	/* Used if this vCPU is waiting for PI notification wakeup. */
+	struct list_head pi_wakeup_list;
+	/* Until here same layout to struct vcpu_pi. */
+
 	u8                    fail;
 	u8		      x2apic_msr_bitmap_mode;
 
@@ -299,12 +307,6 @@ struct vcpu_vmx {
 
 	union vmx_exit_reason exit_reason;
 
-	/* Posted interrupt descriptor */
-	struct pi_desc pi_desc;
-
-	/* Used if this vCPU is waiting for PI notification wakeup. */
-	struct list_head pi_wakeup_list;
-
 	/* Support for a guest hypervisor (nested VMX) */
 	struct nested_vmx nested;
 
-- 
2.46.0