virtio,pci,pc: fixes, features

[PULL 09/27] hw/pci: Fix SR-IOV VF number calculation

Michael S. Tsirkin posted 27 patches 6 months ago

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Maintainers: "Michael S. Tsirkin" <mst@redhat.com>, Stefano Garzarella <sgarzare@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Raphael Norwitz <raphael@enfabrica.net>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Laurent Vivier <lvivier@redhat.com>, Amit Shah <amit@kernel.org>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Jonathan Cameron <jonathan.cameron@huawei.com>, Fan Ni <fan.ni@samsung.com>, Igor Mammedov <imammedo@redhat.com>, Ani Sinha <anisinha@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, Jason Wang <jasowang@redhat.com>, Yi Liu <yi.l.liu@intel.com>, "Clément Mathieu--Drif" <clement.mathieu--drif@eviden.com>, Gerd Hoffmann <kraxel@redhat.com>, Fam Zheng <fam@euphon.net>, Alex Williamson <alex.williamson@redhat.com>, "Cédric Le Goater" <clg@redhat.com>, "Alex Bennée" <alex.bennee@linaro.org>, David Hildenbrand <david@redhat.com>, "Gonglei (Arei)" <arei.gonglei@huawei.com>, Eric Auger <eric.auger@redhat.com>

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[PULL 09/27] hw/pci: Fix SR-IOV VF number calculation

Posted by Michael S. Tsirkin 6 months ago

From: Akihiko Odaki <akihiko.odaki@daynix.com>

pci_config_get_bar_addr() had a division by vf_stride. vf_stride needs
to be non-zero when there are multiple VFs, but the specification does
not prohibit to make it zero when there is only one VF.

Do not perform the division for the first VF to avoid division by zero.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20250314-sriov-v9-2-57dae8ae3ab5@daynix.com>
Tested-by: Yui Washizu <yui.washidu@gmail.com>
Tested-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/pci/pci.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 6d9d3ce90f..039cf1e256 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1594,7 +1594,11 @@ static pcibus_t pci_config_get_bar_addr(PCIDevice *d, int reg,
             pci_get_word(pf->config + sriov_cap + PCI_SRIOV_VF_OFFSET);
         uint16_t vf_stride =
             pci_get_word(pf->config + sriov_cap + PCI_SRIOV_VF_STRIDE);
-        uint32_t vf_num = (d->devfn - (pf->devfn + vf_offset)) / vf_stride;
+        uint32_t vf_num = d->devfn - (pf->devfn + vf_offset);
+
+        if (vf_num) {
+            vf_num /= vf_stride;
+        }
 
         if (type & PCI_BASE_ADDRESS_MEM_TYPE_64) {
             new_addr = pci_get_quad(pf->config + bar);
-- 
MST