From patchwork Sun Aug 7 22:01:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Isaku Yamahata X-Patchwork-Id: 12938317 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52278C19F2A for ; Sun, 7 Aug 2022 22:05:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235601AbiHGWFG (ORCPT ); Sun, 7 Aug 2022 18:05:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235423AbiHGWDN (ORCPT ); Sun, 7 Aug 2022 18:03:13 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 078B3A44F; Sun, 7 Aug 2022 15:02:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1659909765; x=1691445765; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=3a+ih7FRJh5gBvNkx9ix8TQ8ndIsktdyHyIRt/WJjrw=; b=WeX2gc59grKm2y38AnBaTTEXSdIeAaPQCwrSjFHLrHvywZGkXnB0ny66 W82nekWModWjj11QeHCkmOHpZKRfxCmQR2hZDOR9D2SYCU0586kDuLXsw CcsNIbxPEKLpNxOehFXTNzfiN3p4YwjkPFcjSH0S4tmhe7BO8D3ZuDL3i qYOgEQ7iAu8b+QZDrTHCcCOjTgZvLausXypa/I/vOfl1PEgGbXT5rOSLU 38dw3z+AphdntbTlpC3oLWG4YIRUYK5VaTV8gqVL4qAgK4VDWgf+Eo5Yy ZhdBtI6qvX2ZXrJs+9Nxlyq4rQl4d5fFkPOBRNOlHZ+U/fSu82waOGAwi w==; X-IronPort-AV: E=McAfee;i="6400,9594,10432"; a="270240366" X-IronPort-AV: E=Sophos;i="5.93,220,1654585200"; d="scan'208";a="270240366" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Aug 2022 15:02:40 -0700 X-IronPort-AV: E=Sophos;i="5.93,220,1654585200"; d="scan'208";a="663682689" Received: from ls.sc.intel.com (HELO localhost) ([143.183.96.54]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Aug 2022 15:02:40 -0700 From: isaku.yamahata@intel.com To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Paolo Bonzini , erdemaktas@google.com, Sean Christopherson , Sagi Shahar Subject: [PATCH v8 074/103] KVM: TDX: Add support for find pending IRQ in a protected local APIC Date: Sun, 7 Aug 2022 15:01:59 -0700 Message-Id: <3b4588f5a22aece712fe1c310f0a156e35cb0c7c.1659854790.git.isaku.yamahata@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Sean Christopherson Add flag and hook to KVM's local APIC management to support determining whether or not a TDX guest as a pending IRQ. For TDX vCPUs, the virtual APIC page is owned by the TDX module and cannot be accessed by KVM. As a result, registers that are virtualized by the CPU, e.g. PPR, cannot be read or written by KVM. To deliver interrupts for TDX guests, KVM must send an IRQ to the CPU on the posted interrupt notification vector. And to determine if TDX vCPU has a pending interrupt, KVM must check if there is an outstanding notification. Return "no interrupt" in kvm_apic_has_interrupt() if the guest APIC is protected to short-circuit the various other flows that try to pull an IRQ out of the vAPIC, the only valid operation is querying _if_ an IRQ is pending, KVM can't do anything based on _which_ IRQ is pending. Intentionally omit sanity checks from other flows, e.g. PPR update, so as not to degrade non-TDX guests with unecessary checks. A well-behaved KVM and userspace will never reach those flows for TDX guests, but reaching them is not fatal if something does go awry. Note, this doesn't handle interrupts that have been delivered to the vCPU but not yet recognized by the core, i.e. interrupts that are sitting in vmcs.GUEST_INTR_STATUS. Querying that state requires a SEAMCALL and will be supported in a future patch. Signed-off-by: Sean Christopherson Signed-off-by: Isaku Yamahata --- arch/x86/include/asm/kvm-x86-ops.h | 1 + arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/irq.c | 3 +++ arch/x86/kvm/lapic.c | 3 +++ arch/x86/kvm/lapic.h | 2 ++ arch/x86/kvm/vmx/main.c | 11 +++++++++++ arch/x86/kvm/vmx/tdx.c | 6 ++++++ arch/x86/kvm/vmx/x86_ops.h | 2 ++ 8 files changed, 29 insertions(+) diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index 9fbef4a98fd4..309ac366ae79 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -112,6 +112,7 @@ KVM_X86_OP_OPTIONAL(pi_update_irte) KVM_X86_OP_OPTIONAL(pi_start_assignment) KVM_X86_OP_OPTIONAL(apicv_post_state_restore) KVM_X86_OP_OPTIONAL_RET0(dy_apicv_has_pending_interrupt) +KVM_X86_OP_OPTIONAL(protected_apic_has_interrupt) KVM_X86_OP_OPTIONAL(set_hv_timer) KVM_X86_OP_OPTIONAL(cancel_hv_timer) KVM_X86_OP(setup_mce) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 75218f7d15ac..ef04220527b2 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1661,6 +1661,7 @@ struct kvm_x86_ops { void (*pi_start_assignment)(struct kvm *kvm); void (*apicv_post_state_restore)(struct kvm_vcpu *vcpu); bool (*dy_apicv_has_pending_interrupt)(struct kvm_vcpu *vcpu); + bool (*protected_apic_has_interrupt)(struct kvm_vcpu *vcpu); int (*set_hv_timer)(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc, bool *expired); diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c index f371f1292ca3..56e52eef0269 100644 --- a/arch/x86/kvm/irq.c +++ b/arch/x86/kvm/irq.c @@ -100,6 +100,9 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v) if (kvm_cpu_has_extint(v)) return 1; + if (lapic_in_kernel(v) && v->arch.apic->guest_apic_protected) + return static_call(kvm_x86_protected_apic_has_interrupt)(v); + return kvm_apic_has_interrupt(v) != -1; /* LAPIC */ } EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt); diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index e2ce3556915e..46422f04b489 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2622,6 +2622,9 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu) if (!kvm_apic_present(vcpu)) return -1; + if (apic->guest_apic_protected) + return -1; + __apic_update_ppr(apic, &ppr); return apic_has_interrupt_for_ppr(apic, ppr); } diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 117a46df5cc1..6264cf52663e 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -65,6 +65,8 @@ struct kvm_lapic { bool sw_enabled; bool irr_pending; bool lvt0_in_nmi_mode; + /* Select registers in the vAPIC cannot be read/written. */ + bool guest_apic_protected; /* Number of bits set in ISR. */ s16 isr_count; /* The highest vector set in ISR; if -1 - invalid, must scan ISR. */ diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c index 8f1af269c387..88ac11504765 100644 --- a/arch/x86/kvm/vmx/main.c +++ b/arch/x86/kvm/vmx/main.c @@ -46,6 +46,9 @@ static __init int vt_hardware_setup(void) enable_tdx = enable_tdx && !tdx_hardware_setup(&vt_x86_ops); + if (!enable_tdx) + vt_x86_ops.protected_apic_has_interrupt = NULL; + if (enable_ept) kvm_mmu_set_ept_masks(enable_ept_ad_bits, cpu_has_vmx_ept_execute_only()); @@ -178,6 +181,13 @@ static void vt_vcpu_load(struct kvm_vcpu *vcpu, int cpu) return vmx_vcpu_load(vcpu, cpu); } +static bool vt_protected_apic_has_interrupt(struct kvm_vcpu *vcpu) +{ + KVM_BUG_ON(!is_td_vcpu(vcpu), vcpu->kvm); + + return tdx_protected_apic_has_interrupt(vcpu); +} + static void vt_flush_tlb_all(struct kvm_vcpu *vcpu) { if (is_td_vcpu(vcpu)) @@ -348,6 +358,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { .sync_pir_to_irr = vmx_sync_pir_to_irr, .deliver_interrupt = vmx_deliver_interrupt, .dy_apicv_has_pending_interrupt = pi_has_pending_interrupt, + .protected_apic_has_interrupt = vt_protected_apic_has_interrupt, .set_tss_addr = vmx_set_tss_addr, .set_identity_map_addr = vmx_set_identity_map_addr, diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 12fe6d0eab36..9ea56be8f0bb 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -513,6 +513,7 @@ int tdx_vcpu_create(struct kvm_vcpu *vcpu) return -EINVAL; fpstate_set_confidential(&vcpu->arch.guest_fpu); + vcpu->arch.apic->guest_apic_protected = true; ret = tdx_alloc_td_page(&tdx->tdvpr); if (ret) @@ -577,6 +578,11 @@ void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) local_irq_enable(); } +bool tdx_protected_apic_has_interrupt(struct kvm_vcpu *vcpu) +{ + return pi_has_pending_interrupt(vcpu); +} + void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) { struct vcpu_tdx *tdx = to_tdx(vcpu); diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h index fb7b5fc5f0dd..7750166a4481 100644 --- a/arch/x86/kvm/vmx/x86_ops.h +++ b/arch/x86/kvm/vmx/x86_ops.h @@ -150,6 +150,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu); void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu); void tdx_vcpu_put(struct kvm_vcpu *vcpu); void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu); +bool tdx_protected_apic_has_interrupt(struct kvm_vcpu *vcpu); int tdx_vm_ioctl(struct kvm *kvm, void __user *argp); int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp); @@ -177,6 +178,7 @@ static inline fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu) { return EXIT_FASTP static inline void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) {} static inline void tdx_vcpu_put(struct kvm_vcpu *vcpu) {} static inline void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) {} +static inline bool tdx_protected_apic_has_interrupt(struct kvm_vcpu *vcpu) { return false; } static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOPNOTSUPP; } static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }