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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5061C7EE2A for ; Wed, 10 May 2023 18:16:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235511AbjEJSQ2 (ORCPT ); Wed, 10 May 2023 14:16:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233128AbjEJSQY (ORCPT ); Wed, 10 May 2023 14:16:24 -0400 Received: from smtp-fw-80009.amazon.com (smtp-fw-80009.amazon.com [99.78.197.220]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 150C66A4E; Wed, 10 May 2023 11:16:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1683742581; x=1715278581; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=aOBZZRpXG65B2FKAr3P8tboz+OImM0VGcypvPR1xbEU=; b=BbK9LeBm4eoHws0kaUds8t91kmCyvduY19JRkryFUXPSV27JTjJM7apS YQnwhfHmM++S54xJ+iFlulhOveT0TKfBIoPiAGOGPExINJm7CvGr1Q5jY XhUh7Z6W+vW1+4NMfqA5NHYs4dywJClwYURu2BeQ5w0oXOj0rv/eEzW7Z 8=; X-IronPort-AV: E=Sophos;i="5.99,265,1677542400"; d="scan'208";a="1984655" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-pdx-2c-m6i4x-d2040ec1.us-west-2.amazon.com) ([10.25.36.214]) by smtp-border-fw-80009.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 May 2023 18:16:19 +0000 Received: from EX19MTAUEA002.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2c-m6i4x-d2040ec1.us-west-2.amazon.com (Postfix) with ESMTPS id 6A2C341471; Wed, 10 May 2023 18:16:18 +0000 (UTC) Received: from EX19D008UEC004.ant.amazon.com (10.252.135.170) by EX19MTAUEA002.ant.amazon.com (10.252.134.9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Wed, 10 May 2023 18:16:18 +0000 Received: from EX19MTAUEA001.ant.amazon.com (10.252.134.203) by EX19D008UEC004.ant.amazon.com (10.252.135.170) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Wed, 10 May 2023 18:16:17 +0000 Received: from dev-dsk-risbhat-2b-8bdc64cd.us-west-2.amazon.com (10.189.73.169) by mail-relay.amazon.com (10.252.134.102) with Microsoft SMTP Server id 15.2.1118.26 via Frontend Transport; Wed, 10 May 2023 18:16:17 +0000 Received: by dev-dsk-risbhat-2b-8bdc64cd.us-west-2.amazon.com (Postfix, from userid 22673075) id 6E0174621; Wed, 10 May 2023 18:16:17 +0000 (UTC) From: Rishabh Bhatnagar To: , CC: , , , , , , , , , , , David Woodhouse , Rishabh Bhatnagar , Allen Pais Subject: [PATCH 8/9] KVM: x86: do not report preemption if the steal time cache is stale Date: Wed, 10 May 2023 18:15:46 +0000 Message-ID: <20230510181547.22451-9-risbhat@amazon.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230510181547.22451-1-risbhat@amazon.com> References: <20230510181547.22451-1-risbhat@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Paolo Bonzini commit c3c28d24d910a746b02f496d190e0e8c6560224b upstream. Commit 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status", 2021-11-11) open coded the previous call to kvm_map_gfn, but in doing so it dropped the comparison between the cached guest physical address and the one in the MSR. This cause an incorrect cache hit if the guest modifies the steal time address while the memslots remain the same. This can happen with kexec, in which case the preempted bit is written at the address used by the old kernel instead of the old one. Cc: David Woodhouse Cc: stable@vger.kernel.org Fixes: 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status") Signed-off-by: Paolo Bonzini Signed-off-by: Rishabh Bhatnagar Tested-by: Allen Pais Acked-by: Sean Christopherson --- arch/x86/kvm/x86.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0503bb8b64e5..8461aa63c251 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4096,6 +4096,7 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) struct kvm_steal_time __user *st; struct kvm_memslots *slots; static const u8 preempted = KVM_VCPU_PREEMPTED; + gpa_t gpa = vcpu->arch.st.msr_val & KVM_STEAL_VALID_BITS; /* * The vCPU can be marked preempted if and only if the VM-Exit was on @@ -4123,6 +4124,7 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) slots = kvm_memslots(vcpu->kvm); if (unlikely(slots->generation != ghc->generation || + gpa != ghc->gpa || kvm_is_error_hva(ghc->hva) || !ghc->memslot)) return; -- 2.39.2