git: 3292a54f1ba9 - stable/13 - LinuxKPI: fix pci_alloc_irq_vectors() for MSI

The branch stable/13 has been updated by bz:

URL: https://cgit.FreeBSD.org/src/commit/?id=3292a54f1ba9ccbc18e15290eb35665dc964b1c3

commit 3292a54f1ba9ccbc18e15290eb35665dc964b1c3
Author:     Bjoern A. Zeeb <bz@FreeBSD.org>
AuthorDate: 2022-11-28 18:05:48 +0000
Commit:     Bjoern A. Zeeb <bz@FreeBSD.org>
CommitDate: 2023-01-18 13:26:44 +0000

    LinuxKPI: fix pci_alloc_irq_vectors() for MSI
    
    pci_alloc_irq_vectors() is given a min and max vector value.
    pci_enable_msi() will always succeed independent of these arguments as
    it does not know about them.  Further it will only ever allocate
    1 "vector" not supporting any other amount.
    So upfront check that (a) the available pci_msi_count() can satisfy the
    requested minv and (b) given the pci_enable_msi() hard coded limit check
    that minv is not larger than 1.
    If we cannot satisfy either requirement return an error.
    
    This fixes problems with drivers which check that the returned value
    of allocated "vectors" will match their requests and only otherwise try
    to fall back to ask for 1 or deal otherwise.
    
    Sponsored by:   The FreeBSD Foundation
    Reviewed by:    hselasky (earlier version)
    Differential Revision: https://reviews.freebsd.org/D37522
    
    (cherry picked from commit e9715b1c4474333ff119aba3a9a74bff91f72372)
---
 sys/compat/linuxkpi/common/src/linux_pci.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sys/compat/linuxkpi/common/src/linux_pci.c b/sys/compat/linuxkpi/common/src/linux_pci.c
index b0820c9b2c3e..a9c859d29623 100644
--- a/sys/compat/linuxkpi/common/src/linux_pci.c
+++ b/sys/compat/linuxkpi/common/src/linux_pci.c
@@ -928,6 +928,11 @@ out:
 			return (pdev->dev.irq_end - pdev->dev.irq_start);
 	}
 	if (flags & PCI_IRQ_MSI) {
+		if (pci_msi_count(pdev->dev.bsddev) < minv)
+			return (-ENOSPC);
+		/* We only support 1 vector in pci_enable_msi() */
+		if (minv != 1)
+			return (-ENOSPC);
 		error = pci_enable_msi(pdev);
 		if (error == 0 && pdev->msi_enabled)
 			return (pdev->dev.irq_end - pdev->dev.irq_start);