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[47.54.130.67]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8eb9becc72dsm169155785a.34.2026.04.20.05.24.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2026 05:24:44 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wEngC-0000000CEWE-0Joa; Mon, 20 Apr 2026 09:24:44 -0300 Date: Mon, 20 Apr 2026 09:24:44 -0300 From: Jason Gunthorpe To: Nazar Mokrynskyi Cc: kvm@vger.kernel.org, alex.williamson@redhat.com, linux-pci@vger.kernel.org Subject: Re: vfio/pci: Qualcomm PCIe WiFi devices drop link during FLR causing host AER crash Message-ID: <20260420122444.GN2577880@ziepe.ca> References: <70de9b8f-b7c7-481b-8cb1-931e3b82eb0e@mokrynskyi.com> Precedence: bulk X-Mailing-List: kvm@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: <70de9b8f-b7c7-481b-8cb1-931e3b82eb0e@mokrynskyi.com> On Sat, Apr 18, 2026 at 12:24:07AM +0300, Nazar Mokrynskyi wrote: > Several Qualcomm PCIe WiFi devices drop their PCIe link as part of their > internal reset sequence. Under bare metal this is transparent because the > host root complex performs link retraining automatically. Under VFIO > passthrough, the link-drop generates an uncorrectable AER error that > escalates through the parent bridge to the host, crashing it. If AER's crash the system then it is not compatible with VFIO, IMHO. For VFIO to work as designed the platform must be able to safely contain all the errors the PCI device can generate. Jason