4.19-stable review patch. If anyone has any objections, please let me know.
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From: Wei Liu wei.liu@kernel.org
commit fea93a3e5d5e6a09eb153866d2ce60ea3287a70d upstream.
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: 4daace0d8ce8 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/controller/pci-hyperv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -650,8 +650,8 @@ static void _hv_pcifront_read_config(str 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