From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1F95531197B for ; Thu, 23 Apr 2026 16:26:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776961592; cv=none; b=OeaCO5RIADNYJr/jB4IXDQzqaNCIRo6dDTw5EQYvYL49Wc5xyR7Ul3u8j03xgk2JJgvmVpSnc5e0dDYWd6TMtumRjPg6DS2vf7fsk30Zlmasa2xFBOWMoLt5V40SKb2pHyOY7xj4gKrSFHgbZWxjwAN99GFqlcUS7k3HxGee/hk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776961592; c=relaxed/simple; bh=2WHR07BM9YZMu9YXVW9q/VNkLnVamHMmal6QfJQU0zA=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=VFQzV8kGDUlns9vSXFXfIEyrcXPQUXxhvL57hy2xybrqMLrL+o6f3OAEexr64KAUZG+TdfHITatUT1AmW7oLKWXmmLJTS5xlSYsc8czVgbnc3rpYGtTuUXgjKunP0utchVPMvRs32jCKirK2iyIB82R0yh4cc88ZP+uDL41XRok= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=FHyrFvps; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FHyrFvps" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-c799a65bad2so3232327a12.0 for ; Thu, 23 Apr 2026 09:26:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1776961590; x=1777566390; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:reply-to:from:to:cc :subject:date:message-id:reply-to; bh=bgKQyFNL/xZdySs4+82GSKr8MJJui3Na6kPKf3Q383U=; b=FHyrFvpsHeO245+Tt3yY3YlLk+YTydYGEDauMTIQvxnl9+88PdSfNWl2Egkb//VR5t SxM1dxetJvVXzCduFZXxS9lRT3fyi7uvwfofoPHpJDaSKuDYFxvjeBUpwBq4z/1mxrtI hxFFtj+sqFy39mhUiCNeEOfZP9W92P9oiIfRbs0XchHNZ6HDYUVoAPIl1wsVo9r3muQi OROr85Z3SXawIJRXT5PlnBTU7ICXGw4P00aMdItFKEx3nXQNZBrB/DfTUrIfayVAB0Kj xTmN8D5gBaze3hx0fldEPzAEBoUKDMdm7rI+BqF0muMT3az7/8k/Ja5IlcUXAQ+3nkhv zrEg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776961590; x=1777566390; h=cc:to:from:subject:message-id:mime-version:date:reply-to :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=bgKQyFNL/xZdySs4+82GSKr8MJJui3Na6kPKf3Q383U=; b=XqO73h1DNWmCntaOLRwGdaIWmSK/7H92Q71nxxEqmldQd7krNa2jExjYs5xbCmkITT 8w+mPenL5GIfJRG0kJEhkvOzDqmiixw6yr7j1ykMSfW/m4BUL0r4UEmiBNAAbTnIQjp3 YV3pVoBDEqKiji22/LxfkzPj8bMVGqSIIYvXe6UGYrALMZPSwjS9isqhgJfaWhq5hg3F E3SfVOccjN0qKA9wRl0zluMOHvCdc4gbamt05tEnRE6Q16x5Q0DZfyxjhEq/OSXL3+cK DhvojGxDuWLX2IrHkSDBScEVQ0Krf3FIHHNyKijsRkoxsBTaGcFCM4roIkIBPskvxAKT 8SAQ== X-Gm-Message-State: AOJu0YzNdph44lHtMFSo1UNPvXy10auwODSj+cPbm7iVtHWGWpXc1qY2 Nvqu0RoTPlbk94ZWc5BU8S2FG9bZDuOrQj+I2CEKQtobcb7t+MP+I6LLdp7BPjOF/bhk7MzNwCI Q2Bwb8Q== X-Received: from pgtt124.prod.google.com ([2002:a63:2d82:0:b0:c73:fbb5:af1b]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:3d90:b0:39c:126c:93b5 with SMTP id adf61e73a8af0-3a08d74e884mr32160120637.21.1776961590228; Thu, 23 Apr 2026 09:26:30 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 23 Apr 2026 09:26:26 -0700 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog Message-ID: <20260423162628.490962-1-seanjc@google.com> Subject: [PATCH 0/2] KVM: x86: Fastpath userspace exit fix and hardening From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, "Nikunj A . Dadhania" Content-Type: text/plain; charset="UTF-8" Fix a found-by-inspection bug where KVM could fail to flush the PML buffer (VMX) or fail to grab the most recet CR0/CR3 (SVM) prior to exiting to userspace, which could prove to be fatal if that exit is that last exit prior to save/restore, e.g. the last exit before userspace commits to migrating the VM. Patch 2 is related hardening, i.e. isn't fixing any existing bugs (AFAIK). Sean Christopherson (2): KVM: x86: Ensure vendor's exit handler runs before fastpath userspace exits KVM: SVM: Refresh vcpu->arch.cr{0,3} prior to invoking fastpath handler arch/x86/kvm/svm/svm.c | 15 ++++++++------- arch/x86/kvm/vmx/vmx.c | 3 +++ arch/x86/kvm/x86.c | 3 --- 3 files changed, 11 insertions(+), 10 deletions(-) base-commit: 85f871f6ba46f20d7fbc0b016b4db648c33220dd -- 2.54.0.545.g6539524ca2-goog