From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) (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 B0E77304BD4; Wed, 5 Nov 2025 10:42:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.20 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762339330; cv=none; b=Tm4oBw+Lq0QkYf2XnCDL0wik1oHRD+/NusU4t6SsVgqyGtZD0WI4BGMGZhPoyK9Fmrv2ApphKZlARwGf35gjanwcEoENitQEnqO8s0c+wSVZCFBwaaBtiQ2ZCzxqDQA3o0ptiRxFwdow7qLZkofZr968pLvDFtaE4bgwl61wVXo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762339330; c=relaxed/simple; bh=1ViRHw8lx988HaKq8748rY8eBv1qH6oDXHX338eSFtQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oRDyma0fa6/8uon6gqjdxOmwmoe+sIjSIaVSo1cr+8DzlcBHnI7BbT+2BPRCDOUriT67vrfU01eZ6OY6epuYPhLw4bafeDN513re2v6YqsXn4R4ReDmROu6XKUBmonT13WmW3+bSjL4L3uYpzDtmbf+k2miarfAChA48LUsWoVU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=LiPDoa+d; arc=none smtp.client-ip=198.175.65.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="LiPDoa+d" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1762339329; x=1793875329; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=1ViRHw8lx988HaKq8748rY8eBv1qH6oDXHX338eSFtQ=; b=LiPDoa+dXu1mWf9v6XBpNmmN1O0pTAnJyJLZ8cVs0cawL+vVjKYaiI+I 3DBc/BUIglQIX6z9cgz/A40vHLUjjZOqYl+39vqr5OeFvIJnkT0M11GmX QQGg2wGbQiH4lepJjIlB6f1JdHQIGUHPMsRRS0gT8P+9fPpxeqe2kVCzQ qgk0h4pIxXEitpE5GzjMfPQA4fmyxs1H2yjk7o5IFeVHeBgzC3K9llOD/ Sonr7B5Zx5UXxTSQcQHOzdnXfRirghbfccaadedhp4C+dQ5TaVekaRLB9 Hz4HDixVY1dnKc3UglPLXAtTauhwX2bbWpCQc2IIxKCTBworppCGjyWcw w==; X-CSE-ConnectionGUID: dsEmGMWMQFOWFWUdV8/j7Q== X-CSE-MsgGUID: Q7T/VMsoSEK+NfjKPOvxnQ== X-IronPort-AV: E=McAfee;i="6800,10657,11603"; a="64145557" X-IronPort-AV: E=Sophos;i="6.19,281,1754982000"; d="scan'208";a="64145557" Received: from fmviesa010.fm.intel.com ([10.60.135.150]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Nov 2025 02:42:09 -0800 X-CSE-ConnectionGUID: IgVkqlvMQd6bQciLaUzw0g== X-CSE-MsgGUID: WXzQ1lwKRUOpBcGYcCeFWA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,281,1754982000"; d="scan'208";a="188147446" Received: from yinghaoj-desk.ccr.corp.intel.com (HELO [10.238.1.225]) ([10.238.1.225]) by fmviesa010-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Nov 2025 02:42:07 -0800 Message-ID: <88404ae2-fa4b-4357-918b-fd949dd2521a@linux.intel.com> Date: Wed, 5 Nov 2025 18:42:04 +0800 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/4] KVM: x86: Load guest/host XCR0 and XSS outside of the fastpath run loop To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jon Kohler References: <20251030224246.3456492-1-seanjc@google.com> <20251030224246.3456492-4-seanjc@google.com> Content-Language: en-US From: Binbin Wu In-Reply-To: <20251030224246.3456492-4-seanjc@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/31/2025 6:42 AM, Sean Christopherson wrote: [...] > > -void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu) > +static void kvm_load_guest_xfeatures(struct kvm_vcpu *vcpu) > { > if (vcpu->arch.guest_state_protected) > return; > > if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) { > - > if (vcpu->arch.xcr0 != kvm_host.xcr0) > xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0); > > @@ -1217,6 +1216,27 @@ void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu) > vcpu->arch.ia32_xss != kvm_host.xss) > wrmsrq(MSR_IA32_XSS, vcpu->arch.ia32_xss); > } > +} > + > +static void kvm_load_host_xfeatures(struct kvm_vcpu *vcpu) > +{ > + if (vcpu->arch.guest_state_protected) > + return; > + > + if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) { > + if (vcpu->arch.xcr0 != kvm_host.xcr0) > + xsetbv(XCR_XFEATURE_ENABLED_MASK, kvm_host.xcr0); > + > + if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) && > + vcpu->arch.ia32_xss != kvm_host.xss) > + wrmsrq(MSR_IA32_XSS, kvm_host.xss); > + } > +} kvm_load_guest_xfeatures() and kvm_load_host_xfeatures() are almost the same except for the guest values VS. host values to set. I am wondering if it is worth adding a helper to dedup the code, like: static void kvm_load_xfeatures(struct kvm_vcpu *vcpu, u64 xcr0, u64 xss) {         if (vcpu->arch.guest_state_protected)                 return;         if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) {                 if (vcpu->arch.xcr0 != kvm_host.xcr0)                         xsetbv(XCR_XFEATURE_ENABLED_MASK, xcr0);                 if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) &&                     vcpu->arch.ia32_xss != kvm_host.xss)                         wrmsrq(MSR_IA32_XSS, xss);         } }