[PATCH 4.11 178/197] PCI: hv: Specify CPU_AFFINITY_ALL for MSI affinity when >= 32 CPUs

[Greg Kroah-Hartman]

4.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>

commit 433fcf6b7b31f1f233dd50aeb9d066a0f6ed4b9d upstream.

When we have 32 or more CPUs in the affinity mask, we should use a special
constant to specify that to the host. Fix this issue.

Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-by: Long Li <longli@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/pci/host/pci-hyperv.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -72,6 +72,7 @@ enum {
 	PCI_PROTOCOL_VERSION_CURRENT = PCI_PROTOCOL_VERSION_1_1
 };
 
+#define CPU_AFFINITY_ALL	-1ULL
 #define PCI_CONFIG_MMIO_LENGTH	0x2000
 #define CFG_PAGE_OFFSET 0x1000
 #define CFG_PAGE_SIZE (PCI_CONFIG_MMIO_LENGTH - CFG_PAGE_OFFSET)
@@ -897,9 +898,13 @@ static void hv_compose_msi_msg(struct ir
 	 * processors because Hyper-V only supports 64 in a guest.
 	 */
 	affinity = irq_data_get_affinity_mask(data);
-	for_each_cpu_and(cpu, affinity, cpu_online_mask) {
-		int_pkt->int_desc.cpu_mask |=
-			(1ULL << vmbus_cpu_number_to_vp_number(cpu));
+	if (cpumask_weight(affinity) >= 32) {
+		int_pkt->int_desc.cpu_mask = CPU_AFFINITY_ALL;
+	} else {
+		for_each_cpu_and(cpu, affinity, cpu_online_mask) {
+			int_pkt->int_desc.cpu_mask |=
+				(1ULL << vmbus_cpu_number_to_vp_number(cpu));
+		}
 	}
 
 	ret = vmbus_sendpacket(hpdev->hbus->hdev->channel, int_pkt,