From 7f8bb7581b7149746bdad9e75e9221f22e5183d8 Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Mon, 1 Jul 2024 20:26:05 +0000 Subject: [PATCH] PCI: hv: Return zero, not garbage, when reading PCI_INTERRUPT_PIN MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Krzysztof Wilczyński Reviewed-by: Michael Kelley Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/pci/controller/pci-hyperv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 2d6c77dcc..d0b3ec237 100755 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -680,8 +680,8 @@ 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