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authorCédric Le Goater <clg@kaod.org>2021-09-30 12:25:35 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2021-10-07 23:33:25 +1100
commit5a4b0320783a19f877dd595813569b3c25f4ff81 (patch)
treee7d80770bd40d4ddf25515b4d419c4d3675ce8d9 /arch
parentf08fb25bc66986b0952724530a640d9970fa52c1 (diff)
downloadlinux-5a4b0320783a19f877dd595813569b3c25f4ff81.tar.bz2
powerpc/pseries/msi: Add an empty irq_write_msi_msg() handler
The IPR drivers tests for MSI support at probe time with MSI vector 0 and when done, frees the IRQ with free_irq(). This test was introduced by 95fecd90397e ("ipr: add test for MSI interrupt support") as an improvement of commit 5a9ef25b14d3 ("[SCSI] ipr: add MSI support") because a boot failure was reported on a Bimini PowerPC system: https://lore.kernel.org/r/1242926159.3007.5.camel@localhost.localdomain It was finally decided to remove MSI support on Bimini systems in 6eb0ac03899a ("powerpc/maple: Add a quirk to disable MSI for IPR on Bimini"). Linux 5.15-rc1 added MSI domain support to the pseries machine and when free_irq is called() in the driver, msi_domain_deactivate() also is. This resets the MSI table entry of the associate vector by calling __pci_write_msi_msg() with an empty message and breaks any further activation of the same vector. In the case of the IPR driver, it breaks the initialization sequence of the IOA. Introduce an empty irq_write_msi_msg() handler in the MSI domain of the pseries machine to avoid clearing the MSI vector entry. Updating the entry is not strictly necessary since it is initialized by the underlying hypervisor, PowerVM or QEMU/KVM. Fixes: a5f3d2c17b07 ("powerpc/pseries/pci: Add MSI domains") Signed-off-by: Cédric Le Goater <clg@kaod.org> Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Tested-by: Mahesh Salgaonkar <mahesh@linux.ibm.com> [mpe: Tweak comment wording and formatting slightly] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210930102535.1047230-1-clg@kaod.org
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/platforms/pseries/msi.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c
index 1b305e411862..8627362f613e 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -507,12 +507,27 @@ static void pseries_msi_unmask(struct irq_data *d)
irq_chip_unmask_parent(d);
}
+static void pseries_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
+{
+ struct msi_desc *entry = irq_data_get_msi_desc(data);
+
+ /*
+ * Do not update the MSIx vector table. It's not strictly necessary
+ * because the table is initialized by the underlying hypervisor, PowerVM
+ * or QEMU/KVM. However, if the MSIx vector entry is cleared, any further
+ * activation will fail. This can happen in some drivers (eg. IPR) which
+ * deactivate an IRQ used for testing MSI support.
+ */
+ entry->msg = *msg;
+}
+
static struct irq_chip pseries_pci_msi_irq_chip = {
.name = "pSeries-PCI-MSI",
.irq_shutdown = pseries_msi_shutdown,
.irq_mask = pseries_msi_mask,
.irq_unmask = pseries_msi_unmask,
.irq_eoi = irq_chip_eoi_parent,
+ .irq_write_msi_msg = pseries_msi_write_msg,
};
static struct msi_domain_info pseries_msi_domain_info = {