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Mon, 2 Nov 2026 07:47:06 +0000 (UTC) Received: from jtornosm-thinkpadp1gen7.rmtes.csb (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id CF1751956087; Mon, 2 Nov 2026 07:46:58 +0000 (UTC) From: Jose Ignacio Tornos Martinez To: jgg@ziepe.ca Cc: alex@shazbot.org, ath11k@lists.infradead.org, ath12k@lists.infradead.org, bhelgaas@google.com, jjohnson@kernel.org, johannes@sipsolutions.net, jtornosm@redhat.com, kevin.tian@intel.com, kvm@vger.kernel.org, kwilczynski@kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-wireless@vger.kernel.org, lpieralisi@kernel.org, mani@kernel.org, pbonzini@redhat.com, robh@kernel.org, seanjc@google.com, vkuznets@redhat.com Subject: Re: [PATCH v3 2/8] KVM: add PCI MSI hypercall for VFIO passthrough Date: Mon, 2 Nov 2026 08:46:57 +0100 Message-ID: <20261102074657.27715-1-jtornosm@redhat.com> In-Reply-To: <20261029165845.GQ1685504@ziepe.ca> References: <20261029165845.GQ1685504@ziepe.ca> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 > This is not quite what I suggested, this still relies on the host > setting up the msi using the trapped MSI emulation, which is the > primary hack.. > > Was it too hard to make this an 'allocate msi' operation? I tried this approach as a simpler mechanism to just read the necessary info from the host side. Ok, I will explore a true allocate operation for the next version. > Yet here it is called alloc? > And this isn't alloc, it is some query.. You are right, the naming was misleading. The implementation was a query, not an allocation. > I feel like VFIO shouldn't be involved here, for the purpose of MSI > all we need is to inform KVM what struct pci_device * is at a vBDF and > then KVM can do the interrupt bits. Maybe this is already happening? > Nothing should use vendor/device ID either, it should all be drive on > vBDF. I appreciate the hint. I will explore the vBDF-based approach without VFIO in the MSI path. > I probably would not have selected this, it is why I suggested > virtio-msi or something that could be optional and seperate from the > core KVM guest ABI. > > But maybe there is interest in doing it this way? Since there was no feedback from KVM maintainers, I will try to follow your guidance more closely for the next version. Thank you for your help Best regards Jose Ignacio