[PATCH v16 110/116] KVM: TDX: Inhibit APICv for TDX guest

From: isaku . yamahata
Date: Mon Oct 16 2023 - 12:59:59 EST


From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

TDX doesn't support APICV, inhibit APICv for TDX guest. Follow how SEV
does it. Define a new inhibit reason for TDX, set it on TD
initialization, and add the flag to kvm_x86_ops.required_apicv_inhibits.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 9 +++++++++
arch/x86/kvm/vmx/main.c | 3 ++-
arch/x86/kvm/vmx/tdx.c | 6 ++++++
3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 529c7e610d47..f0674ef1c17e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1284,6 +1284,15 @@ enum kvm_apicv_inhibit {
* mapping between logical ID and vCPU.
*/
APICV_INHIBIT_REASON_LOGICAL_ID_ALIASED,
+
+ /*********************************************************/
+ /* INHIBITs that are relevant only to the Intel's APICv. */
+ /*********************************************************/
+
+ /*
+ * APICv is disabled because TDX doesn't support it.
+ */
+ APICV_INHIBIT_REASON_TDX,
};

struct kvm_arch {
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index eb44f5784f18..5d61f5306ae3 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -1001,7 +1001,8 @@ static int vt_vcpu_mem_enc_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
BIT(APICV_INHIBIT_REASON_BLOCKIRQ) | \
BIT(APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED) | \
BIT(APICV_INHIBIT_REASON_APIC_ID_MODIFIED) | \
- BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED))
+ BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED) | \
+ BIT(APICV_INHIBIT_REASON_TDX))

struct kvm_x86_ops vt_x86_ops __initdata = {
.name = KBUILD_MODNAME,
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 527fbcd7e2c5..924cbf97404a 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -2486,6 +2486,8 @@ static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params,
goto teardown;
}

+ kvm_set_apicv_inhibit(kvm, APICV_INHIBIT_REASON_TDX);
+
return 0;

/*
@@ -2849,6 +2851,10 @@ static int tdx_td_vcpu_init(struct kvm_vcpu *vcpu, u64 vcpu_rcx)
}

vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+
+ WARN_ON_ONCE(kvm_apicv_activated(vcpu->kvm));
+ vcpu->arch.apic->apicv_active = false;
+
return 0;

free_tdvpx:
--
2.25.1