From patchwork Fri Feb 21 16:33:51 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 13985947 Received: from out-189.mta0.migadu.com (out-189.mta0.migadu.com [91.218.175.189]) (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 A3CDA21128D for ; Fri, 21 Feb 2025 16:34:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.189 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740155654; cv=none; b=iXu8GecwvWMeDKOu2+ANOJWxT3aM2JGS81ILa5biIEaSYrr3yUGMNfbGkH1UjGukIwOmBA3ZPVvhIEpdXAdxM+nBjXvhFydlvfblwOc7YBM5fr42CkVwzyJhP79HPQTREps8hTmN+idrMLVIKakTuW65abAx2LxD5AdXhmHnhGA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740155654; c=relaxed/simple; bh=YXp7VZBdS3IyMkWci8sv6ipPQLiGOAkk2P8v6sqOrS8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=V++Sjz5305Ak0IjwrMl+XW1F+dRlCiFocVUIwObW+9H3dnN2Wp+v5ZOu3vQfy2MooC/KDJ1qAx82lmbSNlOtf0/BXleO5JYrSzm7eN5gWwUGQgWqkRghm4pKHcw+xJjzgu/Rcm+MvSxDdngbop8EsI14wYMWVKB6vUlwjmH6A8E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=k/jmITgm; arc=none smtp.client-ip=91.218.175.189 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="k/jmITgm" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1740155650; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kJ4r4UkNHVRp0o1mave86XFAreLgoybFLmy+ftaGobA=; b=k/jmITgmEj30FvHYDBUb5/TklLz/pGUrveHxVGS2lN6Z+2AlvJUDKMs3YDAJl9fgPkfjCM GDc2jvzwKMiFOT4fbr6dm7rgaztqF3H4HnsOFW4uLmvIYe61rEuvUSHh2uFwbuKKb1p8MI 8qOYjO05xoqHB5vvfp3dGsn4fvK5uaU= From: Yosry Ahmed To: x86@kernel.org, Sean Christopherson Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Paolo Bonzini , Jim Mattson , "Kaplan, David" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed Subject: [PATCH 2/3] KVM: x86: Propagate AMD's IbrsSameMode to the guest Date: Fri, 21 Feb 2025 16:33:51 +0000 Message-ID: <20250221163352.3818347-3-yosry.ahmed@linux.dev> In-Reply-To: <20250221163352.3818347-1-yosry.ahmed@linux.dev> References: <20250221163352.3818347-1-yosry.ahmed@linux.dev> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT If IBRS provides same mode (kernel/user or host/guest) protection on the host, then by definition it also provides same mode protection in the guest. In fact, all different modes from the guest's perspective are the same mode from the host's perspective anyway. Propagate IbrsSameMode to the guests. Signed-off-by: Yosry Ahmed --- arch/x86/kvm/cpuid.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index edef30359c198..05d7bbfbb8885 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -1103,6 +1103,7 @@ void kvm_set_cpu_caps(void) F(AMD_SSB_NO), F(AMD_STIBP), F(AMD_STIBP_ALWAYS_ON), + F(AMD_IBRS_SAME_MODE), F(AMD_PSFD), F(AMD_IBPB_RET), );