From nobody Wed Dec 17 14:38:13 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2CE9CDB483 for ; Wed, 18 Oct 2023 19:41:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231682AbjJRTlO (ORCPT ); Wed, 18 Oct 2023 15:41:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231536AbjJRTlM (ORCPT ); Wed, 18 Oct 2023 15:41:12 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06A8795 for ; Wed, 18 Oct 2023 12:41:10 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5a7d1816bccso109853997b3.1 for ; Wed, 18 Oct 2023 12:41:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1697658069; x=1698262869; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=XDwbLiOis3SdrHxTO/Y/lxRhpLoGiD6x3/AIUgIhLVk=; b=225mPG4bn22vpmEQZ/lq+lcwjZcVmHd/UgrRyJJQv/nh9BGjJUbzh4ACMeF6r9ZggD Tim2wJUR0TlkYG+5oMCTYa9+FgGhyroQo1nuaGeFHdlJgNTmP4xzvBFCKQLlkXfXaW/h 0R2meemQK9REEx3buTD4LUdnDReM4przJQSAX6ezEr5oxWaoKpwu2W2S+I0eFy8O9ymK ZM9+nbK4y0dEW4YK0QrokjdR+O1at/X62oDDoF2yGN7UWvz7VxivEiaz4Fve1p8ExpWj kCba5caUEh77WN8mSQ7pczcJlYmalwYmRhwrSPdMYuRlW/t3ngLDMfDT2W/FX8169bOX gjGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697658069; x=1698262869; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=XDwbLiOis3SdrHxTO/Y/lxRhpLoGiD6x3/AIUgIhLVk=; b=IKcC3S0tpvRglJRhOyFj/HWOSCHqt6rCw4cn/dynDsm2z9TXP336/Ltay53fOLaMOi dfCyWhHAFf1zgYcm0heIzGrKaIRZmU+zSCIxVdEI68NRxNlyLKwpjuSpDedz4lMLwD6x 5FiIpteYtUy1xBJWSdo11rzFaiNk9HEARpgzIRVIWAnF+oyULWT6Azp8XL72uyeVEMTO NbXz0S2ykF5Ph/py8xVkrHImoU9RLAuXS33pr4jv/soGQq5gkwmfdA9+ibO8ku4jaZLa cCG/3dR8qNgijaQ1PICMtHuI5xK6j1LoHUjiEBpksyJ4d5VTcikWFp0kSp830ZepFP+3 kF9Q== X-Gm-Message-State: AOJu0Yw29UJtpFgPhjhuR6owLAoByg2b+MU//aMzS5/JHAc+plr/6O1H udYhJ5pPYpc49UwGuaG+90Ndrs0vzjw= X-Google-Smtp-Source: AGHT+IEE1wVrW556Cd5uDxyOx/0Ua1tTpL0wLSYC675igkSjSvLsIaByHuL9JyEvU5bZFTNu2xBMZmFUKKA= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a0d:ca46:0:b0:5a2:3de0:24a9 with SMTP id m67-20020a0dca46000000b005a23de024a9mr6913ywd.1.1697658069288; Wed, 18 Oct 2023 12:41:09 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 18 Oct 2023 12:41:03 -0700 In-Reply-To: <20231018194104.1896415-1-seanjc@google.com> Mime-Version: 1.0 References: <20231018194104.1896415-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.655.g421f12c284-goog Message-ID: <20231018194104.1896415-2-seanjc@google.com> Subject: [PATCH 1/2] Revert "nSVM: Check for reserved encodings of TLB_CONTROL in nested VMCB" From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Sterz Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Revert KVM's made-up consistency check on SVM's TLB control. The APM says that unsupported encodings are reserved, but the APM doesn't state that VMRUN checks for a supported encoding. Unless something is called out in "Canonicalization and Consistency Checks" or listed as MBZ (Must Be Zero), AMD behavior is typically to let software shoot itself in the foot. This reverts commit 174a921b6975ef959dd82ee9e8844067a62e3ec1. Fixes: 174a921b6975 ("nSVM: Check for reserved encodings of TLB_CONTROL in = nested VMCB") Reported-by: Stefan Sterz Closes: https://lkml.kernel.org/r/b9915c9c-4cf6-051a-2d91-44cc6380f455%40pr= oxmox.com Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Reviewed-by: Maxim Levitsky --- arch/x86/kvm/svm/nested.c | 15 --------------- 1 file changed, 15 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 3fea8c47679e..60891b9ce25f 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -247,18 +247,6 @@ static bool nested_svm_check_bitmap_pa(struct kvm_vcpu= *vcpu, u64 pa, u32 size) kvm_vcpu_is_legal_gpa(vcpu, addr + size - 1); } =20 -static bool nested_svm_check_tlb_ctl(struct kvm_vcpu *vcpu, u8 tlb_ctl) -{ - /* Nested FLUSHBYASID is not supported yet. */ - switch(tlb_ctl) { - case TLB_CONTROL_DO_NOTHING: - case TLB_CONTROL_FLUSH_ALL_ASID: - return true; - default: - return false; - } -} - static bool __nested_vmcb_check_controls(struct kvm_vcpu *vcpu, struct vmcb_ctrl_area_cached *control) { @@ -278,9 +266,6 @@ static bool __nested_vmcb_check_controls(struct kvm_vcp= u *vcpu, IOPM_SIZE))) return false; =20 - if (CC(!nested_svm_check_tlb_ctl(vcpu, control->tlb_ctl))) - return false; - if (CC((control->int_ctl & V_NMI_ENABLE_MASK) && !vmcb12_is_intercept(control, INTERCEPT_NMI))) { return false; --=20 2.42.0.655.g421f12c284-goog