[PATCH 1/2] pci-hyperv: Fix a bug in specifying CPU affinity

From: kys
Date: Fri Mar 24 2017 - 14:09:04 EST


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

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>
Cc: <stable@xxxxxxxxxxxxxxx>
---
drivers/pci/host/pci-hyperv.c | 11 ++++++++---
1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index ada9856..32a16fb 100644
--- 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 irq_data *data, struct msi_msg *msg)
* 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,
--
1.7.1