From patchwork Wed Feb 7 17:26:31 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13548874 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.11]) (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 0D10E127B40; Wed, 7 Feb 2024 17:59:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.11 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707328754; cv=none; b=NhpX6zDodKTMSnKnai/ywGt+We0mUna8mztBlNTB1Pwjwsykf6FU96a/uFf88XzvRadnkCA35VbF/FjiXSbzPJRzxXs608/FN5Hk3wifXjycZLmoTdt/whdKisAWWf1UIprwK6eqlhOPSq2MH4o5cWr9US3Y7HBVpjsmvqNgCcI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707328754; c=relaxed/simple; bh=yTi4kr3PlzXNPrwqknVaKsYqhBkec/CNGRO3VuNenIU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D128TCLDPMq5OzUb+E8n/Nz0S6jcS2Kv9j6EOygWpihi5cpIMSfwMLzoPksuDe/un7MgeaZmXZYtGvmdiUpA3a39hP0jNZjosR+15MzmVPocLhOcqr3o1IDykYnRL8egcKSwqJG0jte/dO8VhlO81zbTphxjwNABvaC6hgYhxUY= 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=OCB9h80F; arc=none smtp.client-ip=198.175.65.11 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="OCB9h80F" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1707328749; x=1738864749; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=yTi4kr3PlzXNPrwqknVaKsYqhBkec/CNGRO3VuNenIU=; b=OCB9h80F7FAanD2ydW1HwX83AWeHVomZP1XI5gtKVGBrJ6QMXttwHb2+ Hed4Wl0a2WKc+5Kvf74/AsOfCe76wej4ZwEOPCqdNUk14GIljTH2GAXy0 wYhbpIb9sS7eD0W/hC1QtunqirRyCuGqbp+ZtpXpz7d0DI1g8WU97wc++ OCqNNm5+oaBk10c/CiwZiM54hjf4aUzKGFh2gyJLHC7kZQnTMSPXPHPiG vxrMGHwg3Dla5aS2vR68X2F7FQsGonot5rNn9DQse3lFLguRlhI0QC44t qnZWsrdftvuP7K9o84sqA89HvThib+nmZ3tSgCwX6l1cNKen5s/zk+zM1 A==; X-IronPort-AV: E=McAfee;i="6600,9927,10977"; a="11622567" X-IronPort-AV: E=Sophos;i="6.05,251,1701158400"; d="scan'208";a="11622567" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Feb 2024 09:58:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,251,1701158400"; d="scan'208";a="6020727" Received: from unknown (HELO fred..) ([172.25.112.68]) by fmviesa004.fm.intel.com with ESMTP; 07 Feb 2024 09:58:56 -0800 From: Xin Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@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, shuah@kernel.org, vkuznets@redhat.com, peterz@infradead.org, ravi.v.shankar@intel.com, xin@zytor.com Subject: [PATCH v2 11/25] KVM: x86: Add kvm_is_fred_enabled() Date: Wed, 7 Feb 2024 09:26:31 -0800 Message-ID: <20240207172646.3981-12-xin3.li@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240207172646.3981-1-xin3.li@intel.com> References: <20240207172646.3981-1-xin3.li@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add kvm_is_fred_enabled() to get if FRED is enabled on a vCPU. Signed-off-by: Xin Li Tested-by: Shan Kang --- Change since v1: * Explain why it is ok to only check CR4.FRED (Chao Gao). --- arch/x86/kvm/kvm_cache_regs.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index 75eae9c4998a..1d431c703fdf 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -187,6 +187,23 @@ 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. + * + * More details at FRED Spec 6.0 Section 4.2 Enabling in CR4. + */ +static __always_inline bool kvm_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))