From nobody Sun Feb 8 10:44:43 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 DF70418658; Mon, 12 Feb 2024 18:32:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707762750; cv=none; b=tIQeRPf2U5sxg7//GXiqCCVdLi/ffZ/d5i2RD7G0lD/Ju6bSDd+pyud/eGI3RQYZikcUJ4VP45s6TNUscTZJmGs2pmww0MvFclS+HBTzjEoFb6MQFNT+5Oq0CCDnwPRoFvD0FbqUIKfwwsoJqNGRqS34SHpFMPDckCLYqBjEcXE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707762750; c=relaxed/simple; bh=yPkH3hOzgZLrY6lJrlZMx8Gh7Q26Rh5ZLHjFNrPwcC0=; h=Date:From:To:Subject:Cc:MIME-Version:Message-ID:Content-Type; b=C4q80m775XGmVXiY9gytWfxgMl87b0thCoxkZEyoibBteqV9cGEY4Ocq0whoxiG4dZR8R+0yYrQEbPhJqsueaP8wzF7PTKNZIYelgiryWw42hQuWt5Lak6oYOoxLV5IcbGOhcs7ABOCY9Uc1Mg0GE7d7hEXzo7ErrN7Ubio0PJk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=3nCWYFnE; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=wal9GZwL; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="3nCWYFnE"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="wal9GZwL" Date: Mon, 12 Feb 2024 18:32:26 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1707762746; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=ZYHpy+obrltc3uNCIQFHHG/TJ4ylG62vxjIjKDv0+7c=; b=3nCWYFnEj4ECw9B+cweR1xfRATYQJu5RlI4PoFbApmF73SsAIuzk+2AJKfvevq2hYn2m5v CGmAgPesmji33O3Su4rGAfxIVmZg03mQvDrkDtsFQkhUWnBxNNPx6aTA/VzJpBi4Cwmi9h 142+iezwo1vUbir9Q/7e0Q9fzKRsCUr8/NQ//Qdu5UCe++F9EdoNsCgkc95VlPb1gBPJkc X6f4f88wPKeDklkKbZtSnlC0xiLLtM2pLX05YIX7ev0nVx4EanHHusWAz3EH5cHojDeAjQ m8Q0R2fnMPxwWX5tvBjCm3BYs3fyD4eP6OH9Fc/WxwX/yQk027tpoatJkaWgbw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1707762746; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=ZYHpy+obrltc3uNCIQFHHG/TJ4ylG62vxjIjKDv0+7c=; b=wal9GZwLTFVHptExbhkoErcgAEgrWOzruf9sc9kud9c8zIMFN5COdcszooWoLaLMtGAsiz K3WDNEUH109apmAw== From: "tip-bot2 for Sean Christopherson" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] KVM/VMX: Use BT+JNC, i.e. EFLAGS.CF to select VMRESUME vs. VMLAUNCH Cc: Sean Christopherson , Pawan Gupta , Dave Hansen , Nikolay Borisov , x86@kernel.org, linux-kernel@vger.kernel.org Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <170776274619.398.641202461394579378.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the x86/urgent branch of tip: Commit-ID: e1920bd6fa76385fbfaf27f5460b60ad1d4c1b9b Gitweb: https://git.kernel.org/tip/e1920bd6fa76385fbfaf27f5460b60ad1= d4c1b9b Author: Sean Christopherson AuthorDate: Sun, 04 Feb 2024 23:20:06 -08:00 Committer: Dave Hansen CommitterDate: Mon, 12 Feb 2024 10:25:22 -08:00 KVM/VMX: Use BT+JNC, i.e. EFLAGS.CF to select VMRESUME vs. VMLAUNCH Use EFLAGS.CF instead of EFLAGS.ZF to track whether to use VMRESUME versus VMLAUNCH. Freeing up EFLAGS.ZF will allow doing VERW, which clobbers ZF, for MDS mitigations as late as possible without needing to duplicate VERW for both paths. Signed-off-by: Sean Christopherson Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Reviewed-by: Nikolay Borisov Link: https://lore.kernel.org/all/20240204-delay-verw-v7-5-59be2d704cb2%40l= inux.intel.com --- arch/x86/kvm/vmx/run_flags.h | 7 +++++-- arch/x86/kvm/vmx/vmenter.S | 6 +++--- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/vmx/run_flags.h b/arch/x86/kvm/vmx/run_flags.h index edc3f16..6a9bfdf 100644 --- a/arch/x86/kvm/vmx/run_flags.h +++ b/arch/x86/kvm/vmx/run_flags.h @@ -2,7 +2,10 @@ #ifndef __KVM_X86_VMX_RUN_FLAGS_H #define __KVM_X86_VMX_RUN_FLAGS_H =20 -#define VMX_RUN_VMRESUME (1 << 0) -#define VMX_RUN_SAVE_SPEC_CTRL (1 << 1) +#define VMX_RUN_VMRESUME_SHIFT 0 +#define VMX_RUN_SAVE_SPEC_CTRL_SHIFT 1 + +#define VMX_RUN_VMRESUME BIT(VMX_RUN_VMRESUME_SHIFT) +#define VMX_RUN_SAVE_SPEC_CTRL BIT(VMX_RUN_SAVE_SPEC_CTRL_SHIFT) =20 #endif /* __KVM_X86_VMX_RUN_FLAGS_H */ diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index 906ecd0..ef7cfba 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -139,7 +139,7 @@ SYM_FUNC_START(__vmx_vcpu_run) mov (%_ASM_SP), %_ASM_AX =20 /* Check if vmlaunch or vmresume is needed */ - test $VMX_RUN_VMRESUME, %ebx + bt $VMX_RUN_VMRESUME_SHIFT, %ebx =20 /* Load guest registers. Don't clobber flags. */ mov VCPU_RCX(%_ASM_AX), %_ASM_CX @@ -161,8 +161,8 @@ SYM_FUNC_START(__vmx_vcpu_run) /* Load guest RAX. This kills the @regs pointer! */ mov VCPU_RAX(%_ASM_AX), %_ASM_AX =20 - /* Check EFLAGS.ZF from 'test VMX_RUN_VMRESUME' above */ - jz .Lvmlaunch + /* Check EFLAGS.CF from the VMX_RUN_VMRESUME bit test above. */ + jnc .Lvmlaunch =20 /* * After a successful VMRESUME/VMLAUNCH, control flow "magically"