From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91B23C2D0A3 for ; Tue, 3 Nov 2020 20:13:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 264E022277 for ; Tue, 3 Nov 2020 20:13:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="eLps2WPR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729286AbgKCUNu (ORCPT ); Tue, 3 Nov 2020 15:13:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728206AbgKCUNu (ORCPT ); Tue, 3 Nov 2020 15:13:50 -0500 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 732CAC0613D1 for ; Tue, 3 Nov 2020 12:13:50 -0800 (PST) Received: by mail-pf1-x441.google.com with SMTP id e7so15226593pfn.12 for ; Tue, 03 Nov 2020 12:13:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=iY26nL+9rKEWM0m+3lcxk7+Si62rVJe06Mcu42M6bNU=; b=eLps2WPRfz+UhZMN+rFlFEz/QpJyAuk8NikrNmy+Uac2l/kduJHngw5wklm60V7Rk5 skpT2065abhdrZOb+hzvc/8TpjDB8qNYqntbu4QZDkYx2Kz1BAYwSHrNUo4WF2eW0df9 E5kA7WnKapMrZjqBRq6CnHXYYGIJ5K+zvHfwE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=iY26nL+9rKEWM0m+3lcxk7+Si62rVJe06Mcu42M6bNU=; b=M4nlVvhQxSvLJgvrWdoGa3IgxKg6I2Ecm0IgmBLFL37U9mKskhwVKvsqYxpGtYmvt5 BSAvzJ6XAKdMQc9tzKmnElrY11gbv21xIyo1zPoSDnTRWWzquL/x8VraEbL5XycApbbF zOZ6QSrwc8yQq+8OLHYTSXnMAqebdai1Y54sTaWdGW/qtWlZrDaGtfdcP9zvLSeYUg+u zOtKcLq7PygXYs6/5WarVZXUPorchOHtNk/6ieAKjhBNvZCsNk6SZXCF3TTb8kCokhhL DzwNfUuAP+76ehzcT9cH2Gz7b5uUPIxcnxRJ86Bz9yqfN+W/YbAywn7ct0jR+E8iyp7a 7/XQ== X-Gm-Message-State: AOAM533n7MLN0lg9Ty28n1WaHBZ6EHkR3yZClCO506nWeVspCheoK8nd VtLqEqbFGdpKAkkMbYCY9ZXesQ== X-Google-Smtp-Source: ABdhPJwNYtsd3305IATRHfux5291SeUk86YsRXGwGoMu6xiGVy+o0U44zhE3ifbVx40ASduNSPGJOg== X-Received: by 2002:a62:fb12:0:b029:160:4c48:b9e1 with SMTP id x18-20020a62fb120000b02901604c48b9e1mr26086509pfm.8.1604434429988; Tue, 03 Nov 2020 12:13:49 -0800 (PST) Received: from smtp.gmail.com ([2620:15c:202:201:3e52:82ff:fe6c:83ab]) by smtp.gmail.com with ESMTPSA id y5sm11622919pfc.165.2020.11.03.12.13.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Nov 2020 12:13:49 -0800 (PST) From: Stephen Boyd To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Marc Zyngier , Will Deacon , Andre Przywara , Steven Price Subject: [PATCH stable 5.4] KVM: arm64: ARM_SMCCC_ARCH_WORKAROUND_1 doesn't return SMCCC_RET_NOT_REQUIRED Date: Tue, 3 Nov 2020 12:13:48 -0800 Message-Id: <20201103201348.371557-1-swboyd@chromium.org> X-Mailer: git-send-email 2.29.1.341.ge80a0c044ae-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit 1de111b51b829bcf01d2e57971f8fd07a665fa3f upstream. According to the SMCCC spec[1](7.5.2 Discovery) the ARM_SMCCC_ARCH_WORKAROUND_1 function id only returns 0, 1, and SMCCC_RET_NOT_SUPPORTED. 0 is "workaround required and safe to call this function" 1 is "workaround not required but safe to call this function" SMCCC_RET_NOT_SUPPORTED is "might be vulnerable or might not be, who knows, I give up!" SMCCC_RET_NOT_SUPPORTED might as well mean "workaround required, except calling this function may not work because it isn't implemented in some cases". Wonderful. We map this SMC call to 0 is SPECTRE_MITIGATED 1 is SPECTRE_UNAFFECTED SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE For KVM hypercalls (hvc), we've implemented this function id to return SMCCC_RET_NOT_SUPPORTED, 0, and SMCCC_RET_NOT_REQUIRED. One of those isn't supposed to be there. Per the code we call arm64_get_spectre_v2_state() to figure out what to return for this feature discovery call. 0 is SPECTRE_MITIGATED SMCCC_RET_NOT_REQUIRED is SPECTRE_UNAFFECTED SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE Let's clean this up so that KVM tells the guest this mapping: 0 is SPECTRE_MITIGATED 1 is SPECTRE_UNAFFECTED SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE Note: SMCCC_RET_NOT_AFFECTED is 1 but isn't part of the SMCCC spec Fixes: c118bbb52743 ("arm64: KVM: Propagate full Spectre v2 workaround state to KVM guests") Signed-off-by: Stephen Boyd Acked-by: Marc Zyngier Acked-by: Will Deacon Cc: Andre Przywara Cc: Steven Price Cc: Marc Zyngier Cc: stable@vger.kernel.org Link: https://developer.arm.com/documentation/den0028/latest [1] Link: https://lore.kernel.org/r/20201023154751.1973872-1-swboyd@chromium.org Signed-off-by: Will Deacon Signed-off-by: Stephen Boyd --- include/linux/arm-smccc.h | 2 ++ virt/kvm/arm/psci.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 080012a6f025..157e4a6a83f6 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -76,6 +76,8 @@ ARM_SMCCC_SMC_32, \ 0, 0x7fff) +#define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED 1 + #ifndef __ASSEMBLY__ #include diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c index 87927f7e1ee7..48fde38d64c3 100644 --- a/virt/kvm/arm/psci.c +++ b/virt/kvm/arm/psci.c @@ -408,7 +408,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) val = SMCCC_RET_SUCCESS; break; case KVM_BP_HARDEN_NOT_REQUIRED: - val = SMCCC_RET_NOT_REQUIRED; + val = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED; break; } break; -- Sent by a computer, using git, on the internet