From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5311E4A20 for ; Sat, 20 Jul 2024 00:01:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721433705; cv=none; b=L2nykuxnHZDpO8E4/maKjiBJ644KgqPbibVchflaAM90IfM+WbYx0Qn3NFhbyYKNsRG6p1eowMLobSKgrkW2q/coS0al9ZoXfkLgeD9WIXHQ2YWcwN8/31WG6qyp79jav11SD2Vhr2FOf+jRXa+GWLy7O+SgL8gZcl0e/QNZNSc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721433705; c=relaxed/simple; bh=oxbgJ+tn2EZ4kaxkAnXDfcMOfnefrqgznqvcIQ/o76o=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Yd4T0jwPSUxHiu7dmKo6T7H474/RQXm+KWsW/w//hvsoAcsI15Rd/dY6Fca5CsBebn091kG3h5e16sDWZAxa3T3YhP66spjV1xDoqSV67MhfwFQMHd2M+eXbQ4Dn5/RR5AqRl/2oErjlaixe+ySMxsvZoA3vTv44rhFNQDaN92Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=UmX39kaO; arc=none smtp.client-ip=209.85.210.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UmX39kaO" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-70afe95d6d5so1366160b3a.0 for ; Fri, 19 Jul 2024 17:01:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1721433703; x=1722038503; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=N1R48DI4ufKXK6suvxcPHvpGEQ7ja9gHKwbShAWyxfY=; b=UmX39kaORfbjVF8HlImftCEHiyXdgAtlqialHc7+SsuHpc5xQegWu6mOACoFCAZbp4 e3R3tIO37ivDAS5crWn+XtvVp2d2wPp+TbgJDp+Kus9vqfgB5NtVk57zwdNqtbbyrsKw a/pjhe/XSVtV2gmx7Er4RoDRXzJq1/lEa5yk2orH4LKF3nN372DPbCiHjUi4EQdb/369 e2luLdIJRqxDg21PAkkTiw/wwFAtxJM3rPqdBIw9ksSW7M6G7CsAf4TT837QkWrNS53Y IhKFYX01LD2nKQRKCegBWr3QTUUseJtft2kXtL/+gCmGvpmIzy01iDn02idG9hvXHXP5 R8bg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721433703; x=1722038503; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=N1R48DI4ufKXK6suvxcPHvpGEQ7ja9gHKwbShAWyxfY=; b=XA1d7achdKzhjuXwGuVGH0pAcj/x2UraMAwMbdq5AB5H2NBTOexBG/rlFjfp+0PHWS IJ11fKkKmkSAfz5bYzC2r+cIGfjaO8x6iIN3qsLRKZmQXgf5v+2qoShZSe7eFaXOFaVy hUdILoEz1m48WD19P1DjNEeoXmmhOZDxHnT8FNTOg/bgMjyWasY0gE6TEzXyNysWPoE1 phgOk3e4Ig5lfAe7EL1ICbGaO1FuZTnty6YKTlpSJ9xAQUgp+vbn1sUgEGSh/a+IlJ/z f//dV0t6zgD2GFACf3P7VQVpEyVuYMlt1hBf6e9b0yfIJOYZPMYlpXLOIBkwWfMp/OGe oiEQ== X-Forwarded-Encrypted: i=1; AJvYcCUcHmz5qiDuhH1/4SqvVT1Es85zhiLGZda6yIWrAiozNG/V7gJh6A8fY0z4Yt8X9PiPODBml24wglN2/c/KHPGRKS9hZjHlqneKokOo X-Gm-Message-State: AOJu0Ywbm/IfPbubr+UXh1P0UC0dqwTgfEfooY+83ofGQlcP1TBZ1Xed ZYeQ2fBxvrrUNS3RfYrRVjrmMp5610xQzJhelKMDv+k2QZxIyvgOw9XUxxJYZdLedsGhO8OfnQo PwQ== X-Google-Smtp-Source: AGHT+IGYGClz9nDahgh9LyCS1O0T5L/ru9OI1rUEfQwloaqtBjqd1EVZlWqGqARPLL9NMvgmBrpCxjGO+0c= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6a00:2a9:b0:70b:5392:a6ef with SMTP id d2e1a72fcca58-70d0877dc15mr4425b3a.3.1721433702597; Fri, 19 Jul 2024 17:01:42 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 19 Jul 2024 17:01:33 -0700 In-Reply-To: <20240720000138.3027780-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240720000138.3027780-1-seanjc@google.com> X-Mailer: git-send-email 2.45.2.1089.g2a221341d9-goog Message-ID: <20240720000138.3027780-2-seanjc@google.com> Subject: [PATCH 1/6] KVM: nVMX: Get to-be-acknowledge IRQ for nested VM-Exit at injection site From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Gao , Zeng Guang Content-Type: text/plain; charset="UTF-8" Move the logic to get the to-be-acknowledge IRQ for a nested VM-Exit from nested_vmx_vmexit() to vmx_check_nested_events(), which is subtly the one and only path where KVM invokes nested_vmx_vmexit() with EXIT_REASON_EXTERNAL_INTERRUPT. A future fix will perform a last-minute check on L2's nested posted interrupt notification vector, just before injecting a nested VM-Exit. To handle that scenario correctly, KVM needs to get the interrupt _before_ injecting VM-Exit, as simply querying the highest priority interrupt, via kvm_cpu_has_interrupt(), would result in TOCTOU bug, as a new, higher priority interrupt could arrive between kvm_cpu_has_interrupt() and kvm_cpu_get_interrupt(). Opportunistically convert the WARN_ON() to a WARN_ON_ONCE(). If KVM has a bug that results in a false positive from kvm_cpu_has_interrupt(), spamming dmesg won't help the situation. Note, nested_vmx_reflect_vmexit() can never reflect external interrupts as they are always "wanted" by L0. Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/nested.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 2392a7ef254d..b3e17635f7e3 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -4284,11 +4284,26 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu) } if (kvm_cpu_has_interrupt(vcpu) && !vmx_interrupt_blocked(vcpu)) { + u32 exit_intr_info; + if (block_nested_events) return -EBUSY; if (!nested_exit_on_intr(vcpu)) goto no_vmexit; - nested_vmx_vmexit(vcpu, EXIT_REASON_EXTERNAL_INTERRUPT, 0, 0); + + if (nested_exit_intr_ack_set(vcpu)) { + int irq; + + irq = kvm_cpu_get_interrupt(vcpu); + WARN_ON_ONCE(irq < 0); + + exit_intr_info = INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR | irq; + } else { + exit_intr_info = 0; + } + + nested_vmx_vmexit(vcpu, EXIT_REASON_EXTERNAL_INTERRUPT, + exit_intr_info, 0); return 0; } @@ -4969,14 +4984,6 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 vm_exit_reason, vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; if (likely(!vmx->fail)) { - if ((u16)vm_exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT && - nested_exit_intr_ack_set(vcpu)) { - int irq = kvm_cpu_get_interrupt(vcpu); - WARN_ON(irq < 0); - vmcs12->vm_exit_intr_info = irq | - INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR; - } - if (vm_exit_reason != -1) trace_kvm_nested_vmexit_inject(vmcs12->vm_exit_reason, vmcs12->exit_qualification, -- 2.45.2.1089.g2a221341d9-goog