From nobody Thu Oct 2 19:27:58 2025 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 38912287515 for ; Fri, 12 Sep 2025 23:23:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757719415; cv=none; b=BojHtYPlHk6nrViC1aUpYQTMgBjjmOVZGdipCsDAwHV//2+tgO4UsbM2Y3XUNAHoh1VDW/72NDbbIXoEOHp4B/8Jt1ucHz+5bEU7YR0cqGOvSPUhPN+sX15xZzfMk9ZW0YToMrGZNulu0hau3oeN703JUxUzgya58q13GcdcSo4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757719415; c=relaxed/simple; bh=G1s+lgWJIgQwzcGoQ1PgYO8Z6+BWK0NfReWmhWVvjvQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=eaOKQKP6gJYdBkE2A60hRp5TskS/JTue8F0x0/MW5o1Y7n+nmIT1L0eshZGqkOS2AQVOOJc3BzHqrp0guwvaxyI0lfwme5n6Kr7jm6t8BH+NDg5YOrDwezqc1vrL+RqFJvO4g2mFMraFD2cUazQ/PNwcEsBT/LvI+4DO8K3Ptx8= 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=AD/w+J5Q; arc=none smtp.client-ip=209.85.214.202 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="AD/w+J5Q" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-248d9301475so35561105ad.0 for ; Fri, 12 Sep 2025 16:23:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1757719414; x=1758324214; 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=chF3amFQqO9S23sbY27BFQPnaf3vHv1B5sQOjntR35k=; b=AD/w+J5QCZuITExYpNFvjdKiMjAHiWaCJbvxlqheufTJrjT6biKq5aCiMy8XDJtDj1 2BnPORt3AbqaHlDF6r+r82q5Im66MHczQ0uf08N5puhp9TRKobjeiBeCOG0QpVRwhTFL XemdE+mXMIFzzWWKRuKiAHtZFZvzV8IlUwuaM/ieT/hEG7GQphjXyMsyDlytMRauMVSA dfplYdIMX7EBZPjXjTioRWJzBExoqcIyJQTuNYLlX9ISBZaykQv3aVb+cHcst2MJuVMX 5yv6OW+QvkKzsHzpX9sYO5e3euTkMHT4M7HHob00CI9YImdvCpPXC+QOrcScvT3ul8gg Nf5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757719414; x=1758324214; 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=chF3amFQqO9S23sbY27BFQPnaf3vHv1B5sQOjntR35k=; b=AtTjZxNGuN8u+il0RO8getUeznHkiWXSBW5RIyY3eScp2vkp4pNW0MeuclvMBWM0W8 uq1VWBDkmSNZL4rHnxj1UD6Dcz6H72bgTzgYKwsqHtbdpj/3BRh7S/TJpwpa6UG/aMQX uGUfm87auzsSfsX7oj0dh5jMOT8aLq8EQQWraJvWcJWQLRJbl1qm8Pr0QjJjxV4BcX+R wcFsgD6o4MWjeH8xFPGT9iFGhQ6ePQOYl0q+Pu351ej3F0M7ys2CNd47hmcn9ArTUh9u NIlW2g13E8RsP6eUbwMMCnTIuEPLJ7RsMD1R5pU1lwqo87LXPAiM1bGui1l/7uIi7tD/ jIrg== X-Forwarded-Encrypted: i=1; AJvYcCXICozJFMiVfP4T3M4VHvXreTQsymqFczypo6op3bzkeaV8Qm0SZghJ0eI8NtCS3mRr1U7U2kugEVEbv40=@vger.kernel.org X-Gm-Message-State: AOJu0Yx+ieGQnT9IMXOKbheo3tW1vDfs+hCLLwUOYXHdAYSQ7kBKMbrN zQAWZubgOgJb90X9AioWZ6PhR2obN3JopqYU7lwWkz9H1py9l8EJdF/RI9gek3ge/e5pHLNmAOG 0j5Y6cg== X-Google-Smtp-Source: AGHT+IFrnFD92ng7tEsW/Py55ME1+YlpgRJlsBgfJ2OrgISj1HLtggF+Ec6syamaoACTlL+jqr8UrabQeAw= X-Received: from plii18.prod.google.com ([2002:a17:902:eb52:b0:25d:510:6240]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:284:b0:24a:9b12:5248 with SMTP id d9443c01a7336-25d27038e28mr51496115ad.54.1757719413616; Fri, 12 Sep 2025 16:23:33 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 12 Sep 2025 16:22:43 -0700 In-Reply-To: <20250912232319.429659-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250912232319.429659-1-seanjc@google.com> X-Mailer: git-send-email 2.51.0.384.g4c02a37b29-goog Message-ID: <20250912232319.429659-6-seanjc@google.com> Subject: [PATCH v15 05/41] KVM: x86: Report XSS as to-be-saved if there are supported features From: Sean Christopherson To: Paolo Bonzini , Sean Christopherson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Tom Lendacky , Mathias Krause , John Allen , Rick Edgecombe , Chao Gao , Maxim Levitsky , Xiaoyao Li , Zhang Yi Z Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add MSR_IA32_XSS to list of MSRs reported to userspace if supported_xss is non-zero, i.e. KVM supports at least one XSS based feature. Before enabling CET virtualization series, guest IA32_MSR_XSS is guaranteed to be 0, i.e., XSAVES/XRSTORS is executed in non-root mode with XSS =3D=3D 0, which equals to the effect of XSAVE/XRSTOR. Signed-off-by: Yang Weijiang Reviewed-by: Maxim Levitsky Reviewed-by: Chao Gao Tested-by: Mathias Krause Tested-by: John Allen Tested-by: Rick Edgecombe Reviewed-by: Xiaoyao Li Signed-off-by: Chao Gao Signed-off-by: Sean Christopherson Reviewed-by: Binbin Wu --- arch/x86/kvm/x86.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 771b7c883c66..3b4258b38ad8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -332,7 +332,7 @@ static const u32 msrs_to_save_base[] =3D { MSR_IA32_RTIT_ADDR3_A, MSR_IA32_RTIT_ADDR3_B, MSR_IA32_UMWAIT_CONTROL, =20 - MSR_IA32_XFD, MSR_IA32_XFD_ERR, + MSR_IA32_XFD, MSR_IA32_XFD_ERR, MSR_IA32_XSS, }; =20 static const u32 msrs_to_save_pmu[] =3D { @@ -7499,6 +7499,10 @@ static void kvm_probe_msr_to_save(u32 msr_index) if (!(kvm_get_arch_capabilities() & ARCH_CAP_TSX_CTRL_MSR)) return; break; + case MSR_IA32_XSS: + if (!kvm_caps.supported_xss) + return; + break; default: break; } --=20 2.51.0.384.g4c02a37b29-goog