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List:       qemu-block
Subject:    [PATCH RFC v4 2/7] hw/pci: Fix SR-IOV VF number calculation
From:       Akihiko Odaki <akihiko.odaki () daynix ! com>
Date:       2024-04-28 9:05:42
Message-ID: 20240428-sriov-v4-2-ac8ac6212982 () daynix ! com
[Download RAW message or body]

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>
---
 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 201ff64e11cc..dbecb3d4aa42 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1437,7 +1437,11 @@ 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);

-- 
2.44.0


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