From patchwork Tue Oct 1 05:00:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xin Li X-Patchwork-Id: 13817448 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 6C301322E; Tue, 1 Oct 2024 05:02:14 +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=1727758936; cv=none; b=ixqzn25kVbx3rvpOfuDkMh3kNCAZWxVgfJ77xqqsVa2fHOzQKD2OJpExtRVDsBLCqq0mGIUXRo6hssNbyOFjA6lwjqdFGo75RMmqMHzIEPZUCnXwyU+RHeRIZPxNqcpyUodkiMxopNOvCkONIJtecMN22T4X9YmI9oLCVKmkYx8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727758936; c=relaxed/simple; bh=WcA6m/Yx90+CLRQ2TAp3UxKRvYuyJoHgvwfYIpMVil8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=r30TSYo44B/sDc3ItiTmgKoIN8DrNCRI5UlXgbMIyM+xQypXBLBKbsSrUv7uTcEIu5IAWSwuJzdtNJdOkS9itSFTjyPcBF6BMP5InETH0Fdkm5XWxghL1JYUDFJi+w22KLSe7Ehz6pos423uZn0stj1UfIIemWaAnuv/EIoUBNE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=fywBXWQT; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="fywBXWQT" Received: from terminus.zytor.com (terminus.zytor.com [IPv6:2607:7c80:54:3:0:0:0:136]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 49151A7c3643828 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 30 Sep 2024 22:01:28 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 49151A7c3643828 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2024091601; t=1727758889; bh=S2anEe6gVhX8RpVekZcYrZwLDqpmlt2eOrTn5hH3hT4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fywBXWQTEL2POH0qz4N+/pCr/+ptIZUSOkqy3nVYI4gf3Ldo0f78XDYsv3HJSKJM0 y23vl6htUKaJ8OooodQM1DhCD7fccqBGLH0nljmJAPl3ZEljsbNCN/zBt7Imfa6SLF g+WEvZb2QTWK+d9l1fzYr5NFuD2s0/VDIpdPGo/9PaHqZk772ykz/LozxSuMrjrFOj zthEYc7mH7lXU50AcVEZCQZKFTgMOmpyyctJvRk5V+iuxQwI1S0mo/pG94dB27uAC+ DRiJSdbiG/CiyHek6aXi7E2xZTTrBbrhAcTHBXeQRrnTaPwJ8kJLQ90rAofOqCsIOq O7ESO8FTUmoGg== From: "Xin Li (Intel)" To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: seanjc@google.com, pbonzini@redhat.com, corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, peterz@infradead.org, andrew.cooper3@citrix.com, xin@zytor.com Subject: [PATCH v3 13/27] KVM: x86: Add a helper to detect if FRED is enabled for a vCPU Date: Mon, 30 Sep 2024 22:00:56 -0700 Message-ID: <20241001050110.3643764-14-xin@zytor.com> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241001050110.3643764-1-xin@zytor.com> References: <20241001050110.3643764-1-xin@zytor.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Xin Li Add is_fred_enabled() to detect if FRED is enabled on a vCPU. Signed-off-by: Xin Li [ Sean: removed the "kvm_" prefix from the function name ] Signed-off-by: Sean Christopherson Signed-off-by: Xin Li (Intel) Tested-by: Shan Kang --- arch/x86/kvm/kvm_cache_regs.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index b1eb46e26b2e..386c79f5dcb8 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -187,6 +187,21 @@ static __always_inline bool kvm_is_cr4_bit_set(struct kvm_vcpu *vcpu, return !!kvm_read_cr4_bits(vcpu, cr4_bit); } +/* + * It's enough to check just CR4.FRED (X86_CR4_FRED) to tell if + * a vCPU is running with FRED enabled, because: + * 1) CR4.FRED can be set to 1 only _after_ IA32_EFER.LMA = 1. + * 2) To leave IA-32e mode, CR4.FRED must be cleared first. + */ +static inline bool is_fred_enabled(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_X86_64 + return kvm_is_cr4_bit_set(vcpu, X86_CR4_FRED); +#else + return false; +#endif +} + static inline ulong kvm_read_cr3(struct kvm_vcpu *vcpu) { if (!kvm_register_is_available(vcpu, VCPU_EXREG_CR3))