From nobody Mon Feb 9 17:56:31 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 73B3C51037; Wed, 13 Mar 2024 16:32:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710347564; cv=none; b=TzeZbLpLfAoAFGfsiHF0ze3swtpLMuE9rujVz9tsSQrTXu3MIRKK59YPHjJAccYGz5dCj+OFCYNl6dcfV02lFt5u2yYWSS2H7Qm1tFJJZZRp1iAQFFgC1cNCVNxuHmqAIeaBlyf5o8ntKL+edGqMAJZYgtGCQgKb0HAm0sGxb00= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710347564; c=relaxed/simple; bh=5itnuw8rkfFsHoEsvM+/W5bVCEbxe4whwlPwsjtLUOo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TGbz6CWnZA71T/tZIdnoBP9Y4DXXM/1JeWxv09vN/1c1h6z4+qmPhSEBncFbVUAm18J0XAv4evTKYSMGwrXi9JFP7ohCUUFJ5z6UfyTSfqe30HqQVUamp2MGid/9zOTu2k5lxhwpxd9LMn/SoMCydnOBC+7Vg1J7lx50JJZgfNg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=A4WMCU1Q; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="A4WMCU1Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 551B6C433F1; Wed, 13 Mar 2024 16:32:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710347564; bh=5itnuw8rkfFsHoEsvM+/W5bVCEbxe4whwlPwsjtLUOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A4WMCU1QGdIKHISLwwUqyKTtieJg7x8Wq8CBf8OLNiBkcIMbTSVT6FDPPj+d9a/rA 7c5wL5ECSnQo24p8nhFFP2dXtdYjVHRMXllx/oYeAZ8WXvVgVugSwoii1J3dK3tC6l 8ngX1INYOj2b4ARejjGpbT+QxlLKAasFkaejdVSIyPy7EzK6Xsj1wCuXZRSJqVKVrE 5SvtdgpZelQP0R+zCdnHs0bp4qO5LVcPT8dlrBftbX+eadl5yQCWiQGrDGe9FMafA2 35ZEE1t/41/CLA5jLMvijvk/nkhAhPHxpMuuLH4l01Tz5C7llBMs1kvsTsEWgxHRcr bSFZdTdilcCSw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Pawan Gupta , Dave Hansen , Thomas Gleixner , Josh Poimboeuf , Greg Kroah-Hartman Subject: [PATCH 6.7 04/61] KVM/x86: Export RFDS_NO and RFDS_CLEAR to guests Date: Wed, 13 Mar 2024 12:31:39 -0400 Message-ID: <20240313163236.613880-5-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240313163236.613880-1-sashal@kernel.org> References: <20240313163236.613880-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.7.10-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-6.7.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 6.7.10-rc1 X-KernelTest-Deadline: 2024-03-15T16:32+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Pawan Gupta commit 2a0180129d726a4b953232175857d442651b55a0 upstream. Mitigation for RFDS requires RFDS_CLEAR capability which is enumerated by MSR_IA32_ARCH_CAPABILITIES bit 27. If the host has it set, export it to guests so that they can deploy the mitigation. RFDS_NO indicates that the system is not vulnerable to RFDS, export it to guests so that they don't deploy the mitigation unnecessarily. When the host is not affected by X86_BUG_RFDS, but has RFDS_NO=3D0, synthesize RFDS_NO to the guest. Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner Acked-by: Josh Poimboeuf Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 468870450b8ba..8021c62b0e7b0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1620,7 +1620,8 @@ static bool kvm_is_immutable_feature_msr(u32 msr) ARCH_CAP_SKIP_VMENTRY_L1DFLUSH | ARCH_CAP_SSB_NO | ARCH_CAP_MDS_NO | \ ARCH_CAP_PSCHANGE_MC_NO | ARCH_CAP_TSX_CTRL_MSR | ARCH_CAP_TAA_NO | \ ARCH_CAP_SBDR_SSDP_NO | ARCH_CAP_FBSDP_NO | ARCH_CAP_PSDP_NO | \ - ARCH_CAP_FB_CLEAR | ARCH_CAP_RRSBA | ARCH_CAP_PBRSB_NO | ARCH_CAP_GDS_NO) + ARCH_CAP_FB_CLEAR | ARCH_CAP_RRSBA | ARCH_CAP_PBRSB_NO | ARCH_CAP_GDS_NO= | \ + ARCH_CAP_RFDS_NO | ARCH_CAP_RFDS_CLEAR) =20 static u64 kvm_get_arch_capabilities(void) { @@ -1652,6 +1653,8 @@ static u64 kvm_get_arch_capabilities(void) data |=3D ARCH_CAP_SSB_NO; if (!boot_cpu_has_bug(X86_BUG_MDS)) data |=3D ARCH_CAP_MDS_NO; + if (!boot_cpu_has_bug(X86_BUG_RFDS)) + data |=3D ARCH_CAP_RFDS_NO; =20 if (!boot_cpu_has(X86_FEATURE_RTM)) { /* --=20 2.43.0