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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Wei Liu <wei.liu@xxxxxxxxxx>

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@xxxxxxxxxx
Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@xxxxxxxxxx>
Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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


Patches currently in stable-queue which might be from wei.liu@xxxxxxxxxx are

queue-4.19/pci-hv-return-zero-not-garbage-when-reading-pci_interrupt_pin.patch




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux