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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8989ECA5FFF for ; Mon, 5 Oct 2026 16:41:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References: List-Owner; bh=ACSssUGKie/5eVZn/j7clwXvC4MTmISK/f7AzHTT/3A=; b=I8syN0lGO6u0x8 JKo6uzjmpINdvmGBBA3x/2lV+XYtHUf8DVBNlPsT0k3AWygK2bRMW/j2yEBPPp5mFqjFL/bizY0Sx lgT7Ujk/xsyfyud6zRVofDVQQDHxk3fMeZB+sJAEUAQI0+qi5v048mng5LtWsgC/Rymg1YZCf0O5M hqU1yM6SGADRSlm8n8eHhv6mzpnL6oGDytb0BLS3C3iIYQHLCdwtFalEmr/7z6r/2pjHCcdJiWAZJ rADv94w1prF4HOrrKsgs373dLU/kiAoHIT+i9cir48AgCi2geGN8BFWYtjkelxyBr8E8rEE3VOxq+ 61tvcdVa1qyPHFiRUxdw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDll4-0000000Gqv7-0I20; Mon, 05 Oct 2026 16:41:46 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDll2-0000000Gqul-2LBy; Mon, 05 Oct 2026 16:41:44 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 75C5860200; Mon, 5 Oct 2026 16:41:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0E841F000FF; Mon, 5 Oct 2026 16:41:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791218503; bh=ACSssUGKie/5eVZn/j7clwXvC4MTmISK/f7AzHTT/3A=; h=Date:From:To:Cc:Subject:In-Reply-To; b=hmEars6ew5+YbrRD+7XLCHSA9cc1J3iBUUrqtEQ7cEbqkGUIC2ch7qbL8VmiPjUQT XlduUY3JUBTpbVMnZx+7LLH9rETL1YIlR+PwqK2+x1iNA60y3QJ4+sYhvWVFhBKm0i MEkiWKRHfQVXfTW82ZNrJ2R3AfKVdKuHLEdmL7FMpxQVwIkoWT8vPUEOnPLnPCHTjw 8Pv+aQmncE1OfyyDaAqYzTbv96s/SCAZh/SviCUvZCmltKHAA0rm0ksnofutqgH2SX cMokhwVuYDjTOFpUKbQSD8k1vKLUskl58yfzGvTyHX+hRbLxdtTqLglJgZEw8KmJZq DwXOhjqIy9FZQ== Date: Mon, 5 Oct 2026 11:41:41 -0500 From: Bjorn Helgaas To: Jose Ignacio Tornos Martinez Cc: bhelgaas@google.com, alex@shazbot.org, mani@kernel.org, jjohnson@kernel.org, linux-pci@vger.kernel.org, linux-wireless@vger.kernel.org, ath11k@lists.infradead.org, ath12k@lists.infradead.org, mhi@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v15 0/2] PCI: Add device-specific reset for Qualcomm devices Message-ID: <20261005164141.GA574887@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261005105436.83962-1-jtornosm@redhat.com> X-BeenThere: ath11k@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "ath11k" Errors-To: ath11k-bounces+ath11k=archiver.kernel.org@lists.infradead.org On Mon, Oct 05, 2026 at 12:54:34PM +0200, Jose Ignacio Tornos Martinez wrote: > Some Qualcomm PCIe devices (WCN6855, WCN7850 WLAN; SDX62/SDX65 modems) > lack working reset methods for VFIO passthrough scenarios. These devices > have no FLR capability, advertise NoSoftRst+ (blocking PM reset), and have > broken bus reset. > > Standard reset methods were already disabled for these devices by commit > 6a4f64c3a3ad ("PCI: Avoid SBR for Qualcomm WCN6855/WCN7850 WiFi, > SDX62/SDX65 modems") because they were not working (quirk_no_bus_reset). > > VFIO attempts to reset devices on every reassignment: > - For the listed modems, without a proper reset capability, these devices > never successfully initialize even on first VM assignment. > - For the listed WLAN devices, without a working reset method, the attempt > fails. On clean VM shutdown, the guest driver properly deinitializes the > device via .shutdown/.remove callbacks, leaving it in a usable state despite > the failed reset. However, on unclean VM termination (crash, force-off), the > guest driver callbacks are not triggered, the device remains in an undefined > state (DMA active, interrupts enabled, etc.), and without a working reset it > cannot be reused. > > Add device-specific reset methods using BAR-space hardware reset registers > that exist in these devices: > > Patch 1: SDX62/SDX65 modem reset via MHI SoC reset > Patch 2: WCN6855/WCN7850 WLAN reset via SoC global reset > > These are true hardware reset mechanisms (not power management or firmware > error recovery), providing proper device reset for VFIO scenarios, allowing > to enforce isolation between successive passthrough users. > > Testing shows stable operation over 100+ VM crash/reset cycles. Device- > specific reset is position #1 in the reset hierarchy, so these devices > will use hardware reset as their primary reset method. > > Jose Ignacio Tornos Martinez (2): > PCI: Add device-specific reset for Qualcomm SDX62/SDX65 modems > PCI: Add device-specific reset for Qualcomm WCN6855/WCN7850 WLAN > > drivers/pci/quirks.c | 116 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 116 insertions(+) Applied to pci/reset for v7.4, thanks! > --- > v15: Address Bjorn Helgaas feedback: > - Explain the relationship with 6a4f64c3a3ad ("PCI: Avoid SBR for Qualcomm > WCN6855/WCN7850 WiFi, SDX62/SDX65 modems") and previous status. > - No code changes from v14, only commit message clarifications (Mani's > Reviewed-by and Alex's Acked-by retained) > v14: https://lore.kernel.org/all/20260917071651.14174-1-jtornosm@redhat.com/ > > -- > 2.54.0 >