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 AD4CEC433FE for ; Fri, 14 Oct 2022 22:27:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229470AbiJNW1D (ORCPT ); Fri, 14 Oct 2022 18:27:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33778 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229513AbiJNW1D (ORCPT ); Fri, 14 Oct 2022 18:27:03 -0400 Received: from smtp-fw-9102.amazon.com (smtp-fw-9102.amazon.com [207.171.184.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C2C91781E7 for ; Fri, 14 Oct 2022 15:27:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1665786423; x=1697322423; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=tJZNea2m1/KOerh3yHR76fNVXbTJz0xM3ObteFENufw=; b=sn8RermBdqwWCZPphLsKrAisoDzBw+JakKPg33NPE52YSKFEVn6gmo93 GF8ELkNywrZL5TWMkWaqqqX9+BsIpALEy+Vd1SBlfDjcp+Ua8/xq+3nHE jHzt6HFTit9a5Ko6L3UKY67MCmtOtgQcoPKeYIBim41WFKgtibTbOnCmN Y=; X-IronPort-AV: E=Sophos;i="5.95,185,1661817600"; d="scan'208";a="269693704" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO email-inbound-relay-iad-1d-10222bbc.us-east-1.amazon.com) ([10.25.36.210]) by smtp-border-fw-9102.sea19.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Oct 2022 22:27:02 +0000 Received: from EX13MTAUEE001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-iad-1d-10222bbc.us-east-1.amazon.com (Postfix) with ESMTPS id 459B31A2AC9; Fri, 14 Oct 2022 22:27:01 +0000 (UTC) Received: from EX19D028UEC004.ant.amazon.com (10.252.137.183) by EX13MTAUEE001.ant.amazon.com (10.43.62.226) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Fri, 14 Oct 2022 22:26:56 +0000 Received: from EX13MTAUEB002.ant.amazon.com (10.43.60.12) by EX19D028UEC004.ant.amazon.com (10.252.137.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.1118.15; Fri, 14 Oct 2022 22:26:55 +0000 Received: from dev-dsk-risbhat-2b-8bdc64cd.us-west-2.amazon.com (10.189.73.169) by mail-relay.amazon.com (10.43.60.234) with Microsoft SMTP Server id 15.0.1497.42 via Frontend Transport; Fri, 14 Oct 2022 22:26:55 +0000 Received: by dev-dsk-risbhat-2b-8bdc64cd.us-west-2.amazon.com (Postfix, from userid 22673075) id 1756028E6; Fri, 14 Oct 2022 22:26:54 +0000 (UTC) From: Rishabh Bhatnagar To: , , CC: , Paolo Bonzini , David Woodhouse , , Rishabh Bhatnagar Subject: [PATCH 8/9] KVM: x86: do not report preemption if the steal time cache is stale Date: Fri, 14 Oct 2022 22:26:42 +0000 Message-ID: <20221014222643.25815-10-risbhat@amazon.com> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20221014222643.25815-1-risbhat@amazon.com> References: <20221014222643.25815-1-risbhat@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: stable@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 --- 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 111aa95f3de3..9e9298c333c8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4089,6 +4089,7 @@ 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 @@ -4116,6 +4117,7 @@ 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; -- 2.37.1