From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A87BD313E36; Mon, 5 Oct 2026 16:41:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791218504; cv=none; b=lQelC+a5pOt9Q6hBYUZalkjGNoqU7s6erOLmtblwvSOHEWE0aZgY9HUFmCn0gxOvvYadXT5XwG1VeAC7EQ5i3BfznfQxM5QdaluE/8FHd9sRlc4PP25uRySY7gvbG3ZIIYqFfZ8EJoM+BJIo4C+wklMK0g5W4znjs/SqrLYAzIk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791218504; c=relaxed/simple; bh=+X2OntxrMTq2KSrF/FK1TbUaOawdn0FYEbaeGy3cIa8=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=bk/ekS7blznSbsrS59suNtJBpd4B8kuKpDksrDi8BkSViGMmN8xWIAB0w/Sh1QSKv3bCuGa7mPYcm4HI1fYuFD+w2SpkNdVJK8Osah/skvFFRzLAJ2/HKMRhyy2qCapQ58C8UjtJZkyYCQ3wa4oFk+ZTmzOkoyzluuO1YutNy2Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hmEars6e; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hmEars6e" 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> 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=us-ascii Content-Disposition: inline In-Reply-To: <20261005105436.83962-1-jtornosm@redhat.com> 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 >