From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 AB078320A3B for ; Tue, 30 Dec 2025 21:14:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767129243; cv=none; b=KfEcwXbC65fp5sIvT3cGqUBpdDD1dUYusXfpirauKc1sD2i+VMsLFoCyWYvmAjq57dk0lVktWGqdF+twtal6bWoo7A4HsoTD4qp2KxUBkSwARCEnu3HrgAPsCD/gAUcRkLwAOQO9OYo01ufUIau40KZ7VKernCKyPNgZXjFGZy0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767129243; c=relaxed/simple; bh=tZZOSec6/iCpiyzfAUT+ddNkhTixOC1p46bySbF1Lsk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=AtDiYfg7DK8wlPyoj2wEfCh9/bUaApcWf+lZvYGPfXzfL82EzNdd3aYHlhV0cBb+v+pQwxmQpwUWTCo6CAw9yU1FREV85vIW477J6NG+i6J5PifS2Vfar+WkEoD/03PP6byXW+IaxfVdDgKo2vKCSx8BLvc1AYt9JSG3wQQQyjY= 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=RTLKa4iJ; arc=none smtp.client-ip=209.85.210.201 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="RTLKa4iJ" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-7c240728e2aso21712035b3a.3 for ; Tue, 30 Dec 2025 13:14:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1767129241; x=1767734041; 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=1VNAutqDSG+oAcPpulLkMbiDreEONHN5ynm2RRYnZD4=; b=RTLKa4iJxEMv0kdR7Ci+DS7Nhisl5cJKuff7pbFxhVp7jOx2HdQ6xE4XOAapvXnFPg 8KhAHFyw8CqW84ukJPUbEOmXcgwHU+g3JDpuze6lXIlPGUySdHsyxTnB2kEw4OLW/Bla Tn+iLc25UgTDRW1nKZ08N+Ks261MSEed73sFPoZ/O8d9W2zXtcg2k4mcYvZTcd/3Aaht tPT/+x7ZF/WJOeWTEpxLopFFJyzwq+WRXvGTAgWuLN3TiTUkLaqWgzxliqYhS1k86J/k nIPtZOBiooVjd5XYitgZigwgia/XgIQ5w4JN8Z4IlMqWnWDtF2Q+gFi+Ett3JyzpOLT6 iVoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767129241; x=1767734041; 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=1VNAutqDSG+oAcPpulLkMbiDreEONHN5ynm2RRYnZD4=; b=GHGFNSfZk07ehs4Huo6rlQ94SR2wcH7hfMRl0ytAnbsG60AaWKHQnV1igQjhiLRvzY uhu6BlcyuWhIp8MNNAV79Nrm/jQQ6ITgzLoVA3R3FAGvIRQDyOOMK8n28ltF1mprZc5y qF+erNxbr4qXbvwB3p7oCyX9GVx01vUWpJs/8OKyFJ1ItPKjXyzv8mQk7ghOLg84Ee7j FOBSEd2cW9b97CcJC23kDY/uPDQvQQiMIuniqKbOAiqcGz9Mf/3AVlWyRhdYCGPXC/nQ FR/q51GMtXtjXSvMIoPlUdI92NjnzixnC8vyzb61QL99n2nWbpcWnvKurtPtOpA3uzVp gYfQ== X-Forwarded-Encrypted: i=1; AJvYcCUVZhB/AD999wHHn9uCgRJt1Ihx+pkTMybAA160JevDjoZ9urRWYrNd1KJI591prlgpghEJjY5iSiIQK3g=@vger.kernel.org X-Gm-Message-State: AOJu0YzHPiKTooCGc9CIF3o4P7x8IEVcPLAxfmRm3gbvQAPOMLXn0Yzi ysS+MZM3p5O+zt44r5QEneBFPx77fsVtrj8mtgQaW8DotWug/Hle96iwRBlXTnG/aCTdM4BO/+9 NjzlNRA== X-Google-Smtp-Source: AGHT+IH7+mef/Yt8vBYVv2MwxPLoJav7Z17cT1/FRzx/Cb02MsEGBMNYfWKFBUDmhPe7ZcDuK/w4obJ/XLg= X-Received: from pjwx15.prod.google.com ([2002:a17:90a:c2cf:b0:34c:64d5:2aa1]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:2591:b0:366:14af:9bbe with SMTP id adf61e73a8af0-376ab2e78f3mr34274847637.72.1767129240895; Tue, 30 Dec 2025 13:14:00 -0800 (PST) Reply-To: Sean Christopherson Date: Tue, 30 Dec 2025 13:13:45 -0800 In-Reply-To: <20251230211347.4099600-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251230211347.4099600-1-seanjc@google.com> X-Mailer: git-send-email 2.52.0.351.gbe84eed79e-goog Message-ID: <20251230211347.4099600-7-seanjc@google.com> Subject: [PATCH v2 6/8] KVM: SVM: Limit incorrect check on SVM_EXIT_ERR to running as a VM From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , Vitaly Kuznetsov , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li Cc: kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson , Yosry Ahmed Content-Type: text/plain; charset="UTF-8" Limit KVM's incorrect check for VMXEXIT_INVALID, a.k.a. SVM_EXIT_ERR, to running as a VM, as detected by X86_FEATURE_HYPERVISOR. The exit_code and all failure codes, e.g. VMXEXIT_INVALID, are 64-bit values, and so checking only bits 31:0 could result in false positives when running on non-broken hardware, e.g. in the extremely unlikely scenario exit code 0xffffffffull is ever generated by hardware. Keep the 32-bit check to play nice with running on broken KVM (for years, KVM has not set bits 63:32 when synthesizing nested SVM VM-Exits). Reviewed-by: Yosry Ahmed Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/svm.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 105f1394026e..f938679c0231 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -425,7 +425,10 @@ static __always_inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu) static inline bool svm_is_vmrun_failure(u64 exit_code) { - return (u32)exit_code == (u32)SVM_EXIT_ERR; + if (cpu_feature_enabled(X86_FEATURE_HYPERVISOR)) + return (u32)exit_code == (u32)SVM_EXIT_ERR; + + return exit_code == SVM_EXIT_ERR; } /* -- 2.52.0.351.gbe84eed79e-goog