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 E2DBAC6FD1C for ; Sun, 12 Mar 2023 18:06:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231990AbjCLSG0 (ORCPT ); Sun, 12 Mar 2023 14:06:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231197AbjCLSD5 (ORCPT ); Sun, 12 Mar 2023 14:03:57 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D49824482; Sun, 12 Mar 2023 10:59:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678643997; x=1710179997; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=XTESiYjQmX50LKuHIzgg9hAlRh6A/Q7nQ/TNcnqaDHs=; b=WkDe+UAymUUf03N4th0+8fSTczs77kogVncvSE+ta3ZMSvlNGcHEFNlR q6k1v1Vj2UxZ9AHDlN5P/uRaQT7HI6JcPZMpeUTqzSaSUrnxPemJddgrP YJQDbp3cUhQmq1ynESj8OYutTgUXs8g/BFxskiAbEfCRuKICYJ+99s4AF K59fjw+2rNH8PoXfqoLGFFl+FK62m9NjK4KgvBEefpEh0FKOH3MTtjSuL vdxvlPqyhqdVLotxGd2ORZM9jj8HVXY0leDkQBddLWfOfHgl/VBtj640W E8s8LRvisyb2hA+lSjv7IDuj8jm1epJrn7+RjzruXtuMXkWl99VyqOVFg Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10647"; a="316659995" X-IronPort-AV: E=Sophos;i="5.98,254,1673942400"; d="scan'208";a="316659995" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Mar 2023 10:58:11 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10647"; a="742596737" X-IronPort-AV: E=Sophos;i="5.98,254,1673942400"; d="scan'208";a="742596737" 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; 12 Mar 2023 10:58:10 -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 , David Matlack , Kai Huang , Zhi Wang Subject: [PATCH v13 074/113] KVM: TDX: Add support for find pending IRQ in a protected local APIC Date: Sun, 12 Mar 2023 10:56:38 -0700 Message-Id: <5ad5e104d9a19735b322459eff3b16b282927d53.1678643052.git.isaku.yamahata@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 unnecessary 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 | 10 ++++++++++ arch/x86/kvm/vmx/tdx.c | 6 ++++++ arch/x86/kvm/vmx/x86_ops.h | 2 ++ 8 files changed, 28 insertions(+) diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index 2681300ce142..e1242c4b248f 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -118,6 +118,7 @@ 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 3e00fd1eb136..23dfb9b89980 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1766,6 +1766,7 @@ 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 b2c397dd2bc6..fd6af5530c32 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 e542cf285b51..b2612a86789f 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2814,6 +2814,9 @@ 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 0a0ea4b5dd8c..749b7b629c47 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -66,6 +66,8 @@ 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 5d7164557c6c..75d74aa79446 100644 --- a/arch/x86/kvm/vmx/main.c +++ b/arch/x86/kvm/vmx/main.c @@ -95,6 +95,8 @@ static __init int vt_hardware_setup(void) if (enable_tdx) vt_x86_ops.tlb_remote_flush = vt_tlb_remote_flush; + else + vt_x86_ops.protected_apic_has_interrupt = NULL; return 0; } @@ -231,6 +233,13 @@ static void vt_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 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)) { @@ -423,6 +432,7 @@ 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 e354fd08cbaf..f0e84f8773e9 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -514,6 +514,7 @@ int tdx_vcpu_create(struct kvm_vcpu *vcpu) return -EINVAL; fpstate_set_confidential(&vcpu->arch.guest_fpu); + vcpu->arch.apic->guest_apic_protected = true; vcpu->arch.efer = EFER_SCE | EFER_LME | EFER_LMA | EFER_NX; @@ -552,6 +553,11 @@ 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 2dace209e7d3..4c788f34b777 100644 --- a/arch/x86/kvm/vmx/x86_ops.h +++ b/arch/x86/kvm/vmx/x86_ops.h @@ -161,6 +161,7 @@ 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); u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio); int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp); @@ -193,6 +194,7 @@ 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 u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) { return 0; } static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; } -- 2.25.1