From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CA1D31F4CA4; Mon, 25 Aug 2025 01:54:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756086843; cv=none; b=lnZ+aQDvoywpikfSksLOl0R63czF25pIVyL0jwJsNnYmH5zECtgUx+Jx3AWURtvm/9U8Qv5wsjRjzqjMUwSXVmSxiEtY55reRcXOgmSCetVERqYoxRUv2tLbLjIA5WeENOnAj3XhVg6E5tGVXdB3KBPHRPMpQgT15OeVrT3Fdhs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756086843; c=relaxed/simple; bh=q2NRu60D+e5X8votf4lAC2BBZ7dibcQeSlMHAF4cpO4=; h=Message-ID:Date:MIME-Version:From:Subject:To:Cc:References: In-Reply-To:Content-Type; b=U2+B3lU2BrhAHRJYIFJLWGJKnceGyUJasux+nmIeW6L2y7F9XdOQsXaRyjhMq9axlC3zQys/e5V10UgP9Z/yS1hynjRS4Tqahe8x3Gg7irmvMzkhjpgbTf82vRVuTprjwM8UkFOosIV0GLQra8mP+irqVUhjxRfWNLvt/j1eKCU= ARC-Authentication-Results:i=1; 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h=Date:From:Subject:To:Cc:References:In-Reply-To:From; b=aORlH73LdDZ7yZLR48yIz9lmJxl3Fwh9YnXtniRfcAg5PqtTAazxWbQEoAyzzK5kG UMaIfjICq63GRLXcUSTqYbwjeBequWS1hXJEBn3M+Q1yZBNBwu/J+eN8oCmO0jfuW7 sponO/JREfkSoQaiFTcItyUuSiKuczIUjURE7isrPClJf7wfvt1iEajX6wb6Yz/c6n QsDohieDNG89DmOjBHstU9nh+PGHVlDpu3TQFUgt9hEEYOo3meFVptlYgLpdyG+M2i QzCWxqKJj1gjynatrrZqxFS0DDmDw6Ec3H8Bz3tZAIN5pW5heDIMRPakt055+M5ICG 0A05RoiXuPWZA== Message-ID: Date: Sun, 24 Aug 2025 18:52:55 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Xin Li Subject: Re: [PATCH v13 05/21] KVM: x86: Load guest FPU state when access XSAVE-managed MSRs To: Chao Gao , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, john.allen@amd.com, mingo@redhat.com, minipli@grsecurity.net, mlevitsk@redhat.com, pbonzini@redhat.com, rick.p.edgecombe@intel.com, seanjc@google.com, tglx@linutronix.de, weijiang.yang@intel.com, x86@kernel.org References: <20250821133132.72322-1-chao.gao@intel.com> <20250821133132.72322-6-chao.gao@intel.com> Content-Language: en-US Autocrypt: addr=xin@zytor.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 6b01c6e9330e..799ac76679c9 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4566,6 +4569,21 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > } > EXPORT_SYMBOL_GPL(kvm_get_msr_common); > > +/* > + * Returns true if the MSR in question is managed via XSTATE, i.e. is context > + * switched with the rest of guest FPU state. > + */ > +static bool is_xstate_managed_msr(u32 index) > +{ > + switch (index) { > + case MSR_IA32_U_CET: Why MSR_IA32_S_CET is not included here? > + case MSR_IA32_PL0_SSP ... MSR_IA32_PL3_SSP: > + return true; > + default: > + return false; > + } > +} Is it better to do? static bool is_xstate_managed_msr(u32 index) { if (!kvm_caps.supported_xss) return false; switch (index) { case MSR_IA32_U_CET: case MSR_IA32_S_CET: case MSR_IA32_PL1_SSP ... MSR_IA32_PL3_SSP: return kvm_caps.supported_xss & XFEATURE_MASK_CET_USER && kvm_caps.supported_xss & XFEATURE_MASK_CET_KERNEL; default: return false; } } And it would be obvious how to add new MSRs related to other XFEATURE bits. Thanks! Xin