Commit 36222b11 authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Paolo Bonzini
Browse files

KVM: x86: don't disable APICv memslot when inhibited 

Thanks to the former patches, it is now possible to keep the APICv
memslot always enabled, and it will be invisible to the guest
when it is inhibited

This code is based on a suggestion from Sean Christopherson:
https://lkml.org/lkml/2021/7/19/2970



Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210810205251.424103-9-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9cc13d60

arch/x86/include/asm/kvm-x86-ops.h

+0 −1
Original line number Diff line number Diff line
@@ -72,7 +72,6 @@ KVM_X86_OP(enable_nmi_window) 
KVM_X86_OP(enable_irq_window)

KVM_X86_OP(update_cr8_intercept)

KVM_X86_OP(check_apicv_inhibit_reasons)

KVM_X86_OP_NULL(pre_update_apicv_exec_ctrl)

KVM_X86_OP(refresh_apicv_exec_ctrl)

KVM_X86_OP(hwapic_irr_update)

KVM_X86_OP(hwapic_isr_update)

arch/x86/include/asm/kvm_host.h

+0 −1
Original line number Diff line number Diff line
@@ -1352,7 +1352,6 @@ struct kvm_x86_ops { 
	void (*enable_irq_window)(struct kvm_vcpu *vcpu);

	void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);

	bool (*check_apicv_inhibit_reasons)(ulong bit);

	void (*pre_update_apicv_exec_ctrl)(struct kvm *kvm, bool activate);

	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);

arch/x86/kvm/svm/avic.c

+6 −15
Original line number Diff line number Diff line
@@ -225,31 +225,26 @@ static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu, 
 * field of the VMCB. Therefore, we set up the

 * APIC_ACCESS_PAGE_PRIVATE_MEMSLOT (4KB) here.

 */

static int avic_update_access_page(struct kvm *kvm, bool activate)

static int avic_alloc_access_page(struct kvm *kvm)

{

	void __user *ret;

	int r = 0;



	mutex_lock(&kvm->slots_lock);

	/*

	 * During kvm_destroy_vm(), kvm_pit_set_reinject() could trigger

	 * APICv mode change, which update APIC_ACCESS_PAGE_PRIVATE_MEMSLOT

	 * memory region. So, we need to ensure that kvm->mm == current->mm.

	 */

	if ((kvm->arch.apic_access_memslot_enabled == activate) ||

	    (kvm->mm != current->mm))



	if (kvm->arch.apic_access_memslot_enabled)

		goto out;



	ret = __x86_set_memory_region(kvm,

				      APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,

				      APIC_DEFAULT_PHYS_BASE,

				      activate ? PAGE_SIZE : 0);

				      PAGE_SIZE);

	if (IS_ERR(ret)) {

		r = PTR_ERR(ret);

		goto out;

	}



	kvm->arch.apic_access_memslot_enabled = activate;

	kvm->arch.apic_access_memslot_enabled = true;

out:

	mutex_unlock(&kvm->slots_lock);

	return r;
@@ -270,7 +265,7 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu) 
	if (kvm_apicv_activated(vcpu->kvm)) {

		int ret;



		ret = avic_update_access_page(vcpu->kvm, true);

		ret = avic_alloc_access_page(vcpu->kvm);

		if (ret)

			return ret;

	}
@@ -918,10 +913,6 @@ bool svm_check_apicv_inhibit_reasons(ulong bit) 
	return supported & BIT(bit);

}



void svm_pre_update_apicv_exec_ctrl(struct kvm *kvm, bool activate)

{

	avic_update_access_page(kvm, activate);

}



static inline int

avic_update_iommu_vcpu_affinity(struct kvm_vcpu *vcpu, int cpu, bool r)

arch/x86/kvm/svm/svm.c

+0 −1
Original line number Diff line number Diff line
@@ -4581,7 +4581,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { 
	.set_virtual_apic_mode = svm_set_virtual_apic_mode,

	.refresh_apicv_exec_ctrl = svm_refresh_apicv_exec_ctrl,

	.check_apicv_inhibit_reasons = svm_check_apicv_inhibit_reasons,

	.pre_update_apicv_exec_ctrl = svm_pre_update_apicv_exec_ctrl,

	.load_eoi_exitmap = svm_load_eoi_exitmap,

	.hwapic_irr_update = svm_hwapic_irr_update,

	.hwapic_isr_update = svm_hwapic_isr_update,

arch/x86/kvm/svm/svm.h

+0 −1
Original line number Diff line number Diff line
@@ -534,7 +534,6 @@ void avic_post_state_restore(struct kvm_vcpu *vcpu); 
void svm_set_virtual_apic_mode(struct kvm_vcpu *vcpu);

void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu);

bool svm_check_apicv_inhibit_reasons(ulong bit);

void svm_pre_update_apicv_exec_ctrl(struct kvm *kvm, bool activate);

void svm_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);

void svm_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr);

void svm_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr);