linux-kernel - [PATCH 22/29] KVM: x86: implement initial plane support

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Message-ID: <20250401161106.790710-23-pbonzini@redhat.com>
Date: Tue,  1 Apr 2025 18:10:59 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: roy.hopkins@...e.com,
	seanjc@...gle.com,
	thomas.lendacky@....com,
	ashish.kalra@....com,
	michael.roth@....com,
	jroedel@...e.de,
	nsaenz@...zon.com,
	anelkz@...zon.de,
	James.Bottomley@...senPartnership.com
Subject: [PATCH 22/29] KVM: x86: implement initial plane support

Implement more of the shared state, namely the PIO emulation area
and ioctl(KVM_RUN).

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/x86.c | 45 +++++++++++++++++++++++++++++++++++----------
 1 file changed, 35 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ebdbd08a840b..d2b43d9b6543 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11567,7 +11567,7 @@ static void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
 	trace_kvm_fpu(0);
 }
 
-int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
+static int kvm_vcpu_ioctl_run_plane(struct kvm_vcpu *vcpu)
 {
 	struct kvm_queued_exception *ex = &vcpu->arch.exception;
 	struct kvm_run *kvm_run = vcpu->run;
@@ -11585,7 +11585,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 
 	kvm_vcpu_srcu_read_lock(vcpu);
 	if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) {
-		if (!vcpu->wants_to_run) {
+		if (!vcpu->plane0->wants_to_run) {
 			r = -EINTR;
 			goto out;
 		}
@@ -11664,7 +11664,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		WARN_ON_ONCE(vcpu->mmio_needed);
 	}
 
-	if (!vcpu->wants_to_run) {
+	if (!vcpu->plane0->wants_to_run) {
 		r = -EINTR;
 		goto out;
 	}
@@ -11687,6 +11687,25 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 	return r;
 }
 
+int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
+{
+	int plane_id = READ_ONCE(vcpu->run->plane);
+	struct kvm_plane *plane = vcpu->kvm->planes[plane_id];
+	int r;
+
+	if (plane_id) {
+		vcpu = kvm_get_plane_vcpu(plane, vcpu->vcpu_id);
+		mutex_lock_nested(&vcpu->mutex, 1);
+	}
+
+	r = kvm_vcpu_ioctl_run_plane(vcpu);
+
+	if (plane_id)
+		mutex_unlock(&vcpu->mutex);
+
+	return r;
+}
+
 static void __get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
 {
 	if (vcpu->arch.emulate_regs_need_sync_to_vcpu) {
@@ -12366,7 +12385,7 @@ static int kvm_init_guest_fpstate(struct kvm_vcpu *vcpu, struct kvm_vcpu *plane0
 
 int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu, struct kvm_plane *plane)
 {
-	struct page *page;
+	struct page *page = NULL;
 	int r;
 
 	vcpu->arch.last_vmentry_cpu = -1;
@@ -12390,10 +12409,15 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu, struct kvm_plane *plane)
 
 	r = -ENOMEM;
 
-	page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
-	if (!page)
-		goto fail_free_lapic;
-	vcpu->arch.pio_data = page_address(page);
+	if (plane->plane) {
+		page = NULL;
+		vcpu->arch.pio_data = vcpu->plane0->arch.pio_data;
+	} else {
+		page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+		if (!page)
+			goto fail_free_lapic;
+		vcpu->arch.pio_data = page_address(page);
+	}
 
 	vcpu->arch.mce_banks = kcalloc(KVM_MAX_MCE_BANKS * 4, sizeof(u64),
 				       GFP_KERNEL_ACCOUNT);
@@ -12451,7 +12475,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu, struct kvm_plane *plane)
 fail_free_mce_banks:
 	kfree(vcpu->arch.mce_banks);
 	kfree(vcpu->arch.mci_ctl2_banks);
-	free_page((unsigned long)vcpu->arch.pio_data);
+	__free_page(page);
 fail_free_lapic:
 	kvm_free_lapic(vcpu);
 fail_mmu_destroy:
@@ -12500,7 +12524,8 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 	idx = srcu_read_lock(&vcpu->kvm->srcu);
 	kvm_mmu_destroy(vcpu);
 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
-	free_page((unsigned long)vcpu->arch.pio_data);
+	if (!vcpu->plane)
+		free_page((unsigned long)vcpu->arch.pio_data);
 	kvfree(vcpu->arch.cpuid_entries);
 }
 
-- 
2.49.0