From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-188.mta0.migadu.com (out-188.mta0.migadu.com [91.218.175.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2211C35C6BA for ; Sat, 25 Jul 2026 03:38:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784950733; cv=none; b=EFalNqCS+/SZ3qlEZR+2UASwQ+Gufj88wE3Dc+605qPFFIgRF/kdLvhZxtR+uygQAeZXgf3o9UojVKzDvDG/VBhBncr5OREj79lfG/K5rlZ/2W7FW3Ig9B/91yiH9z8ZyCtGENLOk3HHYh1OX8H48hFUpAuct2s6GoUdac0I2XE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784950733; c=relaxed/simple; bh=KGCx/nUcIojj4vVTa6HmTLP9goi3xspND1XCcM374O4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=JbBkp+/715mUI8Tog3hm9u2xsmyCPIXd60PhLgbQB93I1Jum0hb+9wW0lDgGBjWFyTVrEJMYaekqb7vUQM74jwNCeVTPPeXOSn6dMFFcbja+8JEj2cZuOgJ3HiKRX0k8Oqnsy49bH+RkOdLe83BoAjqHu7V3GZd4VPkc8k2WdMg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=iKF+GRiG; arc=none smtp.client-ip=91.218.175.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="iKF+GRiG" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784950719; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KGCx/nUcIojj4vVTa6HmTLP9goi3xspND1XCcM374O4=; b=iKF+GRiGygLAprAR6P9dJ71OP21m5FbXml04PBnFayOuSZ8C5fBgh4o2BVdpnCb8ms6Z+y xmv4VlLaUPyQI2vUftCWQZJeXc9BeZr3RXIe2nfqhgHcI6DRD2mrc/O/Yje054GluUlJVa 7fKT0Ej89cBZ9F5tFlMU2UZwEPddsRI= From: Tao Cui To: zeng_chi911@163.com Cc: chenhuacai@kernel.org, kernel@xen0n.name, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, maobibo@loongson.cn, stable@vger.kernel.org, zengchi@kylinos.cn, zhaotianrui@loongson.cn, cui.tao@linux.dev, cuitao@kylinos.cn Subject: Re: [PATCH 1/2] LoongArch: KVM: Fix PC double advance in kernel MMIO read fast path Date: Sat, 25 Jul 2026 11:38:20 +0800 Message-ID: <20260725033820.21904-1-cui.tao@linux.dev> In-Reply-To: <20260723111552.1623996-1-zeng_chi911@163.com> References: <20260723111552.1623996-1-zeng_chi911@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Tao Cui > In the in-kernel MMIO read fast path of kvm_emu_mmio_read(), > kvm_complete_mmio_read() already advances the guest PC via update_pc(). > The explicit update_pc() call right after it advances the PC a second > time, so PC moves forward by 8 instead of 4 and the instruction > following the MMIO read is silently skipped. Good catch! Reviewed-by: Tao Cui