[PATCH 0/5] KVM: x86: Move apicv_active into kvm_lapic

[PATCH 0/5] KVM: x86: Move apicv_active into kvm_lapic

[Sean Christopherson]

Move apicv_active into struct kvm_lapic; KVM enables APICv if and only if
a VM/vCPU has an in-kernel APIC.

This was posted a while back as a one-off patch in an APICv cleanup[*].
The idea and most of the changes remain the same, though I eked out a few
more cleanups.

[*] https://lore.kernel.org/all/20211022004927.1448382-4-seanjc@google.com/

Sean Christopherson (5):
  KVM: SVM: Drop unused AVIC / kvm_x86_ops declarations
  KVM: x86: Drop @vcpu parameter from kvm_x86_ops.hwapic_isr_update()
  KVM: x86: Check for in-kernel xAPIC when querying APICv for directed
    yield
  KVM: x86: Move "apicv_active" into "struct kvm_lapic"
  KVM: x86: Use lapic_in_kernel() to query in-kernel APIC in APICv
    helper

 arch/x86/include/asm/kvm_host.h |  3 +--
 arch/x86/kvm/lapic.c            | 38 ++++++++++++---------------------
 arch/x86/kvm/lapic.h            |  3 ++-
 arch/x86/kvm/svm/svm.c          |  5 +++--
 arch/x86/kvm/svm/svm.h          |  4 ----
 arch/x86/kvm/vmx/vmx.c          |  5 +++--
 arch/x86/kvm/x86.c              | 14 ++++++------
 7 files changed, 31 insertions(+), 41 deletions(-)


base-commit: 8baacf67c76c560fed954ac972b63e6e59a6fba0
-- 
2.36.1.476.g0c4daa206d-goog

[PATCH 1/5] KVM: SVM: Drop unused AVIC / kvm_x86_ops declarations

[Sean Christopherson]

Drop a handful of unused AVIC function declarations whose implementations
were removed during the conversion to optional static calls.

No functional change intended.

Fixes: abb6d479e226 ("KVM: x86: make several APIC virtualization callbacks optional")
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/svm/svm.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 128993feb4c6..d51de3c9264a 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -617,12 +617,8 @@ int avic_init_vcpu(struct vcpu_svm *svm);
 void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
 void avic_vcpu_put(struct kvm_vcpu *vcpu);
 void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu);
-void avic_set_virtual_apic_mode(struct kvm_vcpu *vcpu);
 void avic_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu);
 bool avic_check_apicv_inhibit_reasons(enum kvm_apicv_inhibit reason);
-void avic_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr);
-void avic_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr);
-bool avic_dy_apicv_has_pending_interrupt(struct kvm_vcpu *vcpu);
 int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
 			uint32_t guest_irq, bool set);
 void avic_vcpu_blocking(struct kvm_vcpu *vcpu);
-- 
2.36.1.476.g0c4daa206d-goog

[PATCH 2/5] KVM: x86: Drop @vcpu parameter from kvm_x86_ops.hwapic_isr_update()

[Sean Christopherson]

Drop the unused @vcpu parameter from hwapic_isr_update().  AMD/AVIC is
unlikely to implement the helper, and VMX/APICv doesn't need the vCPU as
it operates on the current VMCS.  The result is somewhat odd, but allows
for a decent amount of (future) cleanup in the APIC code.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 arch/x86/kvm/lapic.c            | 8 ++++----
 arch/x86/kvm/vmx/vmx.c          | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7e98b2876380..16acc54d49a7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1517,7 +1517,7 @@ struct kvm_x86_ops {
 	bool (*check_apicv_inhibit_reasons)(enum kvm_apicv_inhibit reason);
 	void (*refresh_apicv_exec_ctrl)(struct kvm_vcpu *vcpu);
 	void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr);
-	void (*hwapic_isr_update)(struct kvm_vcpu *vcpu, int isr);
+	void (*hwapic_isr_update)(int isr);
 	bool (*guest_apic_has_interrupt)(struct kvm_vcpu *vcpu);
 	void (*load_eoi_exitmap)(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
 	void (*set_virtual_apic_mode)(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index a413a1d8df4c..cc0da5671eb9 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -556,7 +556,7 @@ static inline void apic_set_isr(int vec, struct kvm_lapic *apic)
 	 * just set SVI.
 	 */
 	if (unlikely(vcpu->arch.apicv_active))
-		static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, vec);
+		static_call_cond(kvm_x86_hwapic_isr_update)(vec);
 	else {
 		++apic->isr_count;
 		BUG_ON(apic->isr_count > MAX_APIC_VECTOR);
@@ -604,7 +604,7 @@ static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
 	 * and must be left alone.
 	 */
 	if (unlikely(vcpu->arch.apicv_active))
-		static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, apic_find_highest_isr(apic));
+		static_call_cond(kvm_x86_hwapic_isr_update)(apic_find_highest_isr(apic));
 	else {
 		--apic->isr_count;
 		BUG_ON(apic->isr_count < 0);
@@ -2457,7 +2457,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 	if (vcpu->arch.apicv_active) {
 		static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
 		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, -1);
-		static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, -1);
+		static_call_cond(kvm_x86_hwapic_isr_update)(-1);
 	}
 
 	vcpu->arch.apic_arb_prio = 0;
@@ -2737,7 +2737,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
 	if (vcpu->arch.apicv_active) {
 		static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
 		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
-		static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, apic_find_highest_isr(apic));
+		static_call_cond(kvm_x86_hwapic_isr_update)(apic_find_highest_isr(apic));
 	}
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 	if (ioapic_in_kernel(vcpu->kvm))
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5e14e4c40007..42f8924a90f4 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6556,7 +6556,7 @@ static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu)
 	put_page(page);
 }
 
-static void vmx_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)
+static void vmx_hwapic_isr_update(int max_isr)
 {
 	u16 status;
 	u8 old;
-- 
2.36.1.476.g0c4daa206d-goog

[PATCH 3/5] KVM: x86: Check for in-kernel xAPIC when querying APICv for directed yield

[Sean Christopherson]

Use kvm_vcpu_apicv_active() to check if APICv is active when seeing if a
vCPU is a candidate for directed yield due to a pending ACPIv interrupt.
This will allow moving apicv_active into kvm_lapic without introducing a
potential NULL pointer deref (kvm_vcpu_apicv_active() effectively adds a
pre-check on the vCPU having an in-kernel APIC).

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/x86.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2318a99139fa..cd554a62eb0f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12375,7 +12375,8 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 
 bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
 {
-	if (vcpu->arch.apicv_active && static_call(kvm_x86_dy_apicv_has_pending_interrupt)(vcpu))
+	if (kvm_vcpu_apicv_active(vcpu) &&
+	    static_call(kvm_x86_dy_apicv_has_pending_interrupt)(vcpu))
 		return true;
 
 	return false;
-- 
2.36.1.476.g0c4daa206d-goog

[PATCH 4/5] KVM: x86: Move "apicv_active" into "struct kvm_lapic"

[Sean Christopherson]

Move the per-vCPU apicv_active flag into KVM's local APIC instance.
APICv is fully dependent on an in-kernel local APIC, but that's not at
all clear when reading the current code due to the flag being stored in
the generic kvm_vcpu_arch struct.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/kvm_host.h |  1 -
 arch/x86/kvm/lapic.c            | 30 ++++++++++--------------------
 arch/x86/kvm/lapic.h            |  3 ++-
 arch/x86/kvm/svm/svm.c          |  5 +++--
 arch/x86/kvm/vmx/vmx.c          |  3 ++-
 arch/x86/kvm/x86.c              | 11 ++++++-----
 6 files changed, 23 insertions(+), 30 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 16acc54d49a7..1038ccb7056a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -663,7 +663,6 @@ struct kvm_vcpu_arch {
 	u64 efer;
 	u64 apic_base;
 	struct kvm_lapic *apic;    /* kernel irqchip context */
-	bool apicv_active;
 	bool load_eoi_exitmap_pending;
 	DECLARE_BITMAP(ioapic_handled_vectors, 256);
 	unsigned long apic_attention;
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index cc0da5671eb9..43c42a580295 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -519,14 +519,11 @@ static inline int apic_find_highest_irr(struct kvm_lapic *apic)
 
 static inline void apic_clear_irr(int vec, struct kvm_lapic *apic)
 {
-	struct kvm_vcpu *vcpu;
-
-	vcpu = apic->vcpu;
-
-	if (unlikely(vcpu->arch.apicv_active)) {
+	if (unlikely(apic->apicv_active)) {
 		/* need to update RVI */
 		kvm_lapic_clear_vector(vec, apic->regs + APIC_IRR);
-		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
+		static_call_cond(kvm_x86_hwapic_irr_update)(apic->vcpu,
+							    apic_find_highest_irr(apic));
 	} else {
 		apic->irr_pending = false;
 		kvm_lapic_clear_vector(vec, apic->regs + APIC_IRR);
@@ -543,19 +540,15 @@ EXPORT_SYMBOL_GPL(kvm_apic_clear_irr);
 
 static inline void apic_set_isr(int vec, struct kvm_lapic *apic)
 {
-	struct kvm_vcpu *vcpu;
-
 	if (__apic_test_and_set_vector(vec, apic->regs + APIC_ISR))
 		return;
 
-	vcpu = apic->vcpu;
-
 	/*
 	 * With APIC virtualization enabled, all caching is disabled
 	 * because the processor can modify ISR under the hood.  Instead
 	 * just set SVI.
 	 */
-	if (unlikely(vcpu->arch.apicv_active))
+	if (unlikely(apic->apicv_active))
 		static_call_cond(kvm_x86_hwapic_isr_update)(vec);
 	else {
 		++apic->isr_count;
@@ -590,12 +583,9 @@ static inline int apic_find_highest_isr(struct kvm_lapic *apic)
 
 static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
 {
-	struct kvm_vcpu *vcpu;
 	if (!__apic_test_and_clear_vector(vec, apic->regs + APIC_ISR))
 		return;
 
-	vcpu = apic->vcpu;
-
 	/*
 	 * We do get here for APIC virtualization enabled if the guest
 	 * uses the Hyper-V APIC enlightenment.  In this case we may need
@@ -603,7 +593,7 @@ static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
 	 * on the other hand isr_count and highest_isr_cache are unused
 	 * and must be left alone.
 	 */
-	if (unlikely(vcpu->arch.apicv_active))
+	if (unlikely(apic->apicv_active))
 		static_call_cond(kvm_x86_hwapic_isr_update)(apic_find_highest_isr(apic));
 	else {
 		--apic->isr_count;
@@ -1584,7 +1574,7 @@ static bool lapic_timer_int_injected(struct kvm_vcpu *vcpu)
 		int vec = reg & APIC_VECTOR_MASK;
 		void *bitmap = apic->regs + APIC_ISR;
 
-		if (vcpu->arch.apicv_active)
+		if (apic->apicv_active)
 			bitmap = apic->regs + APIC_IRR;
 
 		if (apic_test_vector(vec, bitmap))
@@ -1701,7 +1691,7 @@ static void apic_timer_expired(struct kvm_lapic *apic, bool from_timer_fn)
 	if (apic_lvtt_tscdeadline(apic) || ktimer->hv_timer_in_use)
 		ktimer->expired_tscdeadline = ktimer->tscdeadline;
 
-	if (!from_timer_fn && vcpu->arch.apicv_active) {
+	if (!from_timer_fn && apic->apicv_active) {
 		WARN_ON(kvm_get_running_vcpu() != vcpu);
 		kvm_apic_inject_pending_timer_irqs(apic);
 		return;
@@ -2379,7 +2369,7 @@ void kvm_apic_update_apicv(struct kvm_vcpu *vcpu)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
 
-	if (vcpu->arch.apicv_active) {
+	if (apic->apicv_active) {
 		/* irr_pending is always true when apicv is activated. */
 		apic->irr_pending = true;
 		apic->isr_count = 1;
@@ -2454,7 +2444,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 
 	vcpu->arch.pv_eoi.msr_val = 0;
 	apic_update_ppr(apic);
-	if (vcpu->arch.apicv_active) {
+	if (apic->apicv_active) {
 		static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
 		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, -1);
 		static_call_cond(kvm_x86_hwapic_isr_update)(-1);
@@ -2734,7 +2724,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
 	kvm_lapic_set_reg(apic, APIC_TMCCT, 0);
 	kvm_apic_update_apicv(vcpu);
 	apic->highest_isr_cache = -1;
-	if (vcpu->arch.apicv_active) {
+	if (apic->apicv_active) {
 		static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
 		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
 		static_call_cond(kvm_x86_hwapic_isr_update)(apic_find_highest_isr(apic));
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 65bb2a8cf145..e09ad97f3250 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -48,6 +48,7 @@ struct kvm_lapic {
 	struct kvm_timer lapic_timer;
 	u32 divide_count;
 	struct kvm_vcpu *vcpu;
+	bool apicv_active;
 	bool sw_enabled;
 	bool irr_pending;
 	bool lvt0_in_nmi_mode;
@@ -204,7 +205,7 @@ static inline int apic_x2apic_mode(struct kvm_lapic *apic)
 
 static inline bool kvm_vcpu_apicv_active(struct kvm_vcpu *vcpu)
 {
-	return vcpu->arch.apic && vcpu->arch.apicv_active;
+	return vcpu->arch.apic && vcpu->arch.apic->apicv_active;
 }
 
 static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index c6cca0ce127b..255f5c6f3aab 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3465,12 +3465,13 @@ void svm_complete_interrupt_delivery(struct kvm_vcpu *vcpu, int delivery_mode,
 				     int trig_mode, int vector)
 {
 	/*
-	 * vcpu->arch.apicv_active must be read after vcpu->mode.
+	 * apic->apicv_active must be read after vcpu->mode.
 	 * Pairs with smp_store_release in vcpu_enter_guest.
 	 */
 	bool in_guest_mode = (smp_load_acquire(&vcpu->mode) == IN_GUEST_MODE);
 
-	if (!READ_ONCE(vcpu->arch.apicv_active)) {
+	/* Note, this is called iff the local APIC is in-kernel. */
+	if (!READ_ONCE(vcpu->arch.apic->apicv_active)) {
 		/* Process the interrupt via inject_pending_event */
 		kvm_make_request(KVM_REQ_EVENT, vcpu);
 		kvm_vcpu_kick(vcpu);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 42f8924a90f4..0e24f2cc3177 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4089,7 +4089,8 @@ static int vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector)
 	if (!r)
 		return 0;
 
-	if (!vcpu->arch.apicv_active)
+	/* Note, this is called iff the local APIC is in-kernel. */
+	if (!vcpu->arch.apic->apicv_active)
 		return -1;
 
 	if (pi_test_and_set_pir(vector, &vmx->pi_desc))
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cd554a62eb0f..9cea051ca62e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9440,7 +9440,7 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu)
 	if (!lapic_in_kernel(vcpu))
 		return;
 
-	if (vcpu->arch.apicv_active)
+	if (vcpu->arch.apic->apicv_active)
 		return;
 
 	if (!vcpu->arch.apic->vapic_addr)
@@ -9893,6 +9893,7 @@ void kvm_make_scan_ioapic_request(struct kvm *kvm)
 
 void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
 {
+	struct kvm_lapic *apic = vcpu->arch.apic;
 	bool activate;
 
 	if (!lapic_in_kernel(vcpu))
@@ -9903,10 +9904,10 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
 
 	activate = kvm_vcpu_apicv_activated(vcpu);
 
-	if (vcpu->arch.apicv_active == activate)
+	if (apic->apicv_active == activate)
 		goto out;
 
-	vcpu->arch.apicv_active = activate;
+	apic->apicv_active = activate;
 	kvm_apic_update_apicv(vcpu);
 	static_call(kvm_x86_refresh_apicv_exec_ctrl)(vcpu);
 
@@ -9916,7 +9917,7 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
 	 * still active when the interrupt got accepted. Make sure
 	 * inject_pending_event() is called to check for that.
 	 */
-	if (!vcpu->arch.apicv_active)
+	if (!apic->apicv_active)
 		kvm_make_request(KVM_REQ_EVENT, vcpu);
 
 out:
@@ -11359,7 +11360,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 		 * will ensure the vCPU gets the correct state before VM-Entry.
 		 */
 		if (enable_apicv) {
-			vcpu->arch.apicv_active = true;
+			vcpu->arch.apic->apicv_active = true;
 			kvm_make_request(KVM_REQ_APICV_UPDATE, vcpu);
 		}
 	} else
-- 
2.36.1.476.g0c4daa206d-goog

[PATCH 5/5] KVM: x86: Use lapic_in_kernel() to query in-kernel APIC in APICv helper

[Sean Christopherson]

Use lapic_in_kernel() in kvm_vcpu_apicv_active() to take advantage of the
kvm_has_noapic_vcpu static branch.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/lapic.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index e09ad97f3250..6207b64b1281 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -205,7 +205,7 @@ static inline int apic_x2apic_mode(struct kvm_lapic *apic)
 
 static inline bool kvm_vcpu_apicv_active(struct kvm_vcpu *vcpu)
 {
-	return vcpu->arch.apic && vcpu->arch.apic->apicv_active;
+	return lapic_in_kernel(vcpu) && vcpu->arch.apic->apicv_active;
 }
 
 static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
-- 
2.36.1.476.g0c4daa206d-goog

Re: [PATCH 2/5] KVM: x86: Drop @vcpu parameter from kvm_x86_ops.hwapic_isr_update()

[Paolo Bonzini]

On 6/15/22 01:05, Sean Christopherson wrote:
> Drop the unused @vcpu parameter from hwapic_isr_update().  AMD/AVIC is
> unlikely to implement the helper, and VMX/APICv doesn't need the vCPU as
> it operates on the current VMCS.  The result is somewhat odd, but allows
> for a decent amount of (future) cleanup in the APIC code.
> 
> No functional change intended.

Yeah, that's a bit odd; what it saves is essentially the apic->vcpu 
dereference.  I don't really like it, so if you want to have a v2 that 
passes the struct kvm_lapic* instead (which is free and keeps irr/isr 
functions consistent), I'll gladly switch.  But I _have_ queued the 
series in the meanwhile, so that's a good reason to ignore me.

Paolo

> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>   arch/x86/include/asm/kvm_host.h | 2 +-
>   arch/x86/kvm/lapic.c            | 8 ++++----
>   arch/x86/kvm/vmx/vmx.c          | 2 +-
>   3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 7e98b2876380..16acc54d49a7 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1517,7 +1517,7 @@ struct kvm_x86_ops {
>   	bool (*check_apicv_inhibit_reasons)(enum kvm_apicv_inhibit reason);
>   	void (*refresh_apicv_exec_ctrl)(struct kvm_vcpu *vcpu);
>   	void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr);
> -	void (*hwapic_isr_update)(struct kvm_vcpu *vcpu, int isr);
> +	void (*hwapic_isr_update)(int isr);
>   	bool (*guest_apic_has_interrupt)(struct kvm_vcpu *vcpu);
>   	void (*load_eoi_exitmap)(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
>   	void (*set_virtual_apic_mode)(struct kvm_vcpu *vcpu);
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index a413a1d8df4c..cc0da5671eb9 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -556,7 +556,7 @@ static inline void apic_set_isr(int vec, struct kvm_lapic *apic)
>   	 * just set SVI.
>   	 */
>   	if (unlikely(vcpu->arch.apicv_active))
> -		static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, vec);
> +		static_call_cond(kvm_x86_hwapic_isr_update)(vec);
>   	else {
>   		++apic->isr_count;
>   		BUG_ON(apic->isr_count > MAX_APIC_VECTOR);
> @@ -604,7 +604,7 @@ static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
>   	 * and must be left alone.
>   	 */
>   	if (unlikely(vcpu->arch.apicv_active))
> -		static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, apic_find_highest_isr(apic));
> +		static_call_cond(kvm_x86_hwapic_isr_update)(apic_find_highest_isr(apic));
>   	else {
>   		--apic->isr_count;
>   		BUG_ON(apic->isr_count < 0);
> @@ -2457,7 +2457,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
>   	if (vcpu->arch.apicv_active) {
>   		static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
>   		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, -1);
> -		static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, -1);
> +		static_call_cond(kvm_x86_hwapic_isr_update)(-1);
>   	}
>   
>   	vcpu->arch.apic_arb_prio = 0;
> @@ -2737,7 +2737,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
>   	if (vcpu->arch.apicv_active) {
>   		static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
>   		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
> -		static_call_cond(kvm_x86_hwapic_isr_update)(vcpu, apic_find_highest_isr(apic));
> +		static_call_cond(kvm_x86_hwapic_isr_update)(apic_find_highest_isr(apic));
>   	}
>   	kvm_make_request(KVM_REQ_EVENT, vcpu);
>   	if (ioapic_in_kernel(vcpu->kvm))
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 5e14e4c40007..42f8924a90f4 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6556,7 +6556,7 @@ static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu)
>   	put_page(page);
>   }
>   
> -static void vmx_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)
> +static void vmx_hwapic_isr_update(int max_isr)
>   {
>   	u16 status;
>   	u8 old;

Re: [PATCH 2/5] KVM: x86: Drop @vcpu parameter from kvm_x86_ops.hwapic_isr_update()

[Sean Christopherson]

On Wed, Jun 15, 2022, Paolo Bonzini wrote:
> On 6/15/22 01:05, Sean Christopherson wrote:
> > Drop the unused @vcpu parameter from hwapic_isr_update().  AMD/AVIC is
> > unlikely to implement the helper, and VMX/APICv doesn't need the vCPU as
> > it operates on the current VMCS.  The result is somewhat odd, but allows
> > for a decent amount of (future) cleanup in the APIC code.
> > 
> > No functional change intended.
> 
> Yeah, that's a bit odd; what it saves is essentially the apic->vcpu
> dereference.  I don't really like it, so if you want to have a v2 that
> passes the struct kvm_lapic* instead (which is free and keeps irr/isr
> functions consistent), I'll gladly switch.  But I _have_ queued the series
> in the meanwhile, so that's a good reason to ignore me.

I'll send a v2 and just drop the patch.  Looking at it again, it's still very odd
and I oversold the cleanup.   And the affected paths are either unlikely() or the
even slower RESET / SET_STATE flows.