From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 3C62E28B415; Mon, 10 Nov 2025 12:54:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762779260; cv=none; b=CbUhhDLOAxCwV2J5cdR08voXMdw8gT2b3PXjdPJ38BZJFj4bGtjnI9/KH4UZ5u2qSPnuA4/39jUtWEAG6c2BXAti1QFRzlxizEXQ0jUnuFs4dV/UVTrODFAsn/KSAZSNh4q1LgeBc5EPPnbbqWQZ+10+734CvrL63gQXQVpPKm4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762779260; c=relaxed/simple; bh=uETkF9u5gsTRV+eVwBh9Qos7gH0lYI7CXbAjujKKzL4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=EaM2LBHRaIAujXiDpMnC8zJHVbUad+LWY4epVzxUsp80MUQUBCr6nfXZSDfq8k1OokQEdgTayKVBNnKjPM4bsXBvS0iDJOMplIB98g8IuT5U+XFnMNdPiDWTOPJ7BllUjW7ESQRzt+bWYNthzLxPyTSbaYGXYC4cSH1KyfUV1wA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=WMWwPWWS; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="WMWwPWWS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1762779259; x=1794315259; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=uETkF9u5gsTRV+eVwBh9Qos7gH0lYI7CXbAjujKKzL4=; b=WMWwPWWSNplEbnb07zmALZ5gq5dUMb1MtAW0VrJyZm0K02gyZEr3kyBR fMSf62VOCeJkuxpiIdg1qTv4WdhdaDWoLIpR1o71+SJmUnk/LmojqsfCb MT15RrfyP6AeDItLsPFq8ZM7hbap9CQbz/uSJUooRp9quBUSljt86YQOM cqE3ZwNbrhQqUA6KWCmGsJPDHtIgovfFiUtlRnr4NydNWky4k16R85Fss EfEQn/G5FxFpeR+O2Vz9GrIa3MfuIBHiOMYXDofdb3D32+sS+EyNadsWQ tXTkumQ+Wyt8V3g72JjBj/97DzdQh/GbCy0y2JfgIbzwYvtBjiBHLCAAe Q==; X-CSE-ConnectionGUID: mlRIuzQhQZSWIajjF5z50Q== X-CSE-MsgGUID: EMplrzYgRgGIkNlrfonCAw== X-IronPort-AV: E=McAfee;i="6800,10657,11609"; a="68686166" X-IronPort-AV: E=Sophos;i="6.19,293,1754982000"; d="scan'208";a="68686166" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Nov 2025 04:54:19 -0800 X-CSE-ConnectionGUID: +EL8QiMWQemBIFPw7/grvA== X-CSE-MsgGUID: Gf6CuqPSSVqrYMoBMViEjQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,293,1754982000"; d="scan'208";a="188622188" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.240.49]) ([10.124.240.49]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Nov 2025 04:54:15 -0800 Message-ID: Date: Mon, 10 Nov 2025 20:54:12 +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 v2] KVM: x86: Add a helper to dedup loading guest/host XCR0 and XSS To: Binbin Wu , seanjc@google.com, pbonzini@redhat.com Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, chao.gao@intel.com References: <20251110050539.3398759-1-binbin.wu@linux.intel.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20251110050539.3398759-1-binbin.wu@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11/10/2025 1:05 PM, Binbin Wu wrote: > Add and use a helper, kvm_load_xfeatures(), to dedup the code that loads > guest/host xfeatures. > > Opportunistically return early if X86_CR4_OSXSAVE is not set to reduce > indentations. > > No functional change intended. > > Suggested-by: Chao Gao > Reviewed-by: Chao Gao > Signed-off-by: Binbin Wu Reviewed-by: Xiaoyao Li > --- > v2: > - Pass a bool to distinguish guest/host. [Chao, Xiaoyao] > - Fix a typo in the short log. [Chao] > - Opportunistically return early if X86_CR4_OSXSAVE is not set to reduce > indentations. > > v1: > - https://lore.kernel.org/kvm/20251106101138.2756175-1-binbin.wu@linux.intel.com > --- > arch/x86/kvm/x86.c | 33 ++++++++++----------------------- > 1 file changed, 10 insertions(+), 23 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 9c2e28028c2b..2c521902e2c6 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1219,34 +1219,21 @@ void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw) > } > EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_lmsw); > > -static void kvm_load_guest_xfeatures(struct kvm_vcpu *vcpu) > +static void kvm_load_xfeatures(struct kvm_vcpu *vcpu, bool load_guest) > { > 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); > - > - if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) && > - 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) > + if (!kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) > 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 (vcpu->arch.xcr0 != kvm_host.xcr0) > + xsetbv(XCR_XFEATURE_ENABLED_MASK, > + load_guest ? vcpu->arch.xcr0 : 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); > - } > + if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) && > + vcpu->arch.ia32_xss != kvm_host.xss) > + wrmsrq(MSR_IA32_XSS, load_guest ? vcpu->arch.ia32_xss : kvm_host.xss); > } > > static void kvm_load_guest_pkru(struct kvm_vcpu *vcpu) > @@ -11333,7 +11320,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) > if (vcpu->arch.guest_fpu.xfd_err) > wrmsrq(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err); > > - kvm_load_guest_xfeatures(vcpu); > + kvm_load_xfeatures(vcpu, true); > > if (unlikely(vcpu->arch.switch_db_regs && > !(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCH))) { > @@ -11429,7 +11416,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) > vcpu->mode = OUTSIDE_GUEST_MODE; > smp_wmb(); > > - kvm_load_host_xfeatures(vcpu); > + kvm_load_xfeatures(vcpu, false); > > /* > * Sync xfd before calling handle_exit_irqoff() which may > > base-commit: 9052f4f6c539ea1fb7b282a34e6bb33154ce0b63