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PCI: hv: Return zero, not garbage, when reading PCI_INTERRUPT_PIN

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The intent of the code snippet is to always return 0 for both
PCI_INTERRUPT_LINE and PCI_INTERRUPT_PIN.

The check misses PCI_INTERRUPT_PIN. This patch fixes that.

This is discovered by this call in VFIO:

    pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, &pin);

The old code does not set *val to 0 because it misses the check for
PCI_INTERRUPT_PIN. Garbage is returned in that case.

Fixes: 4daace0d8c ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs")
Link: https://lore.kernel.org/linux-pci/20240701202606.129606-1-wei.liu@kernel.org
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Cc: stable@kernel.org
This commit is contained in:
Wei Liu 2024-07-01 20:26:05 +00:00 committed by Krzysztof Wilczyński
parent 1613e604df
commit fea93a3e5d
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GPG Key ID: 7C64768D3DE334E7
1 changed files with 2 additions and 2 deletions
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4
drivers/pci/controller/pci-hyperv.c
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@ -1130,8 +1130,8 @@ static void _hv_pcifront_read_config(struct hv_pci_dev *hpdev, int where,
PCI_CAPABILITY_LIST) {
/* ROM BARs are unimplemented */
*val = 0;
} else if (where >= PCI_INTERRUPT_LINE && where + size <=
PCI_INTERRUPT_PIN) {
} else if ((where >= PCI_INTERRUPT_LINE && where + size <= PCI_INTERRUPT_PIN) ||
(where >= PCI_INTERRUPT_PIN && where + size <= PCI_MIN_GNT)) {
/*
* Interrupt Line and Interrupt PIN are hard-wired to zero
* because this front-end only supports message-signaled