Patch "PCI: hv: Specify CPU_AFFINITY_ALL for MSI affinity when >= 32 CPUs" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    PCI: hv: Specify CPU_AFFINITY_ALL for MSI affinity when >= 32 CPUs

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-hv-specify-cpu_affinity_all-for-msi-affinity-when-32-cpus.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 433fcf6b7b31f1f233dd50aeb9d066a0f6ed4b9d Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" <kys@microsoft.com>
Date: Fri, 24 Mar 2017 11:07:21 -0700
Subject: PCI: hv: Specify CPU_AFFINITY_ALL for MSI affinity when >= 32 CPUs

From: K. Y. Srinivasan <kys@microsoft.com>

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@microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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)
@@ -889,9 +890,13 @@ 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,


Patches currently in stable-queue which might be from kys@microsoft.com are

queue-4.9/pci-hv-allocate-interrupt-descriptors-with-gfp_atomic.patch
queue-4.9/pci-hv-specify-cpu_affinity_all-for-msi-affinity-when-32-cpus.patch