summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--drivers/pci/controller/pci-hyperv.c90
1 files changed, 75 insertions, 15 deletions
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index ba64284eaf9f..f1ec8931dfbc 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1613,7 +1613,7 @@ out:
}
static u32 hv_compose_msi_req_v1(
- struct pci_create_interrupt *int_pkt, const struct cpumask *affinity,
+ struct pci_create_interrupt *int_pkt,
u32 slot, u8 vector, u16 vector_count)
{
int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE;
@@ -1632,6 +1632,35 @@ static u32 hv_compose_msi_req_v1(
}
/*
+ * The vCPU selected by hv_compose_multi_msi_req_get_cpu() and
+ * hv_compose_msi_req_get_cpu() is a "dummy" vCPU because the final vCPU to be
+ * interrupted is specified later in hv_irq_unmask() and communicated to Hyper-V
+ * via the HVCALL_RETARGET_INTERRUPT hypercall. But the choice of dummy vCPU is
+ * not irrelevant because Hyper-V chooses the physical CPU to handle the
+ * interrupts based on the vCPU specified in message sent to the vPCI VSP in
+ * hv_compose_msi_msg(). Hyper-V's choice of pCPU is not visible to the guest,
+ * but assigning too many vPCI device interrupts to the same pCPU can cause a
+ * performance bottleneck. So we spread out the dummy vCPUs to influence Hyper-V
+ * to spread out the pCPUs that it selects.
+ *
+ * For the single-MSI and MSI-X cases, it's OK for hv_compose_msi_req_get_cpu()
+ * to always return the same dummy vCPU, because a second call to
+ * hv_compose_msi_msg() contains the "real" vCPU, causing Hyper-V to choose a
+ * new pCPU for the interrupt. But for the multi-MSI case, the second call to
+ * hv_compose_msi_msg() exits without sending a message to the vPCI VSP, so the
+ * original dummy vCPU is used. This dummy vCPU must be round-robin'ed so that
+ * the pCPUs are spread out. All interrupts for a multi-MSI device end up using
+ * the same pCPU, even though the vCPUs will be spread out by later calls
+ * to hv_irq_unmask(), but that is the best we can do now.
+ *
+ * With Hyper-V in Nov 2022, the HVCALL_RETARGET_INTERRUPT hypercall does *not*
+ * cause Hyper-V to reselect the pCPU based on the specified vCPU. Such an
+ * enhancement is planned for a future version. With that enhancement, the
+ * dummy vCPU selection won't matter, and interrupts for the same multi-MSI
+ * device will be spread across multiple pCPUs.
+ */
+
+/*
* Create MSI w/ dummy vCPU set targeting just one vCPU, overwritten
* by subsequent retarget in hv_irq_unmask().
*/
@@ -1640,18 +1669,39 @@ static int hv_compose_msi_req_get_cpu(const struct cpumask *affinity)
return cpumask_first_and(affinity, cpu_online_mask);
}
-static u32 hv_compose_msi_req_v2(
- struct pci_create_interrupt2 *int_pkt, const struct cpumask *affinity,
- u32 slot, u8 vector, u16 vector_count)
+/*
+ * Make sure the dummy vCPU values for multi-MSI don't all point to vCPU0.
+ */
+static int hv_compose_multi_msi_req_get_cpu(void)
{
+ static DEFINE_SPINLOCK(multi_msi_cpu_lock);
+
+ /* -1 means starting with CPU 0 */
+ static int cpu_next = -1;
+
+ unsigned long flags;
int cpu;
+ spin_lock_irqsave(&multi_msi_cpu_lock, flags);
+
+ cpu_next = cpumask_next_wrap(cpu_next, cpu_online_mask, nr_cpu_ids,
+ false);
+ cpu = cpu_next;
+
+ spin_unlock_irqrestore(&multi_msi_cpu_lock, flags);
+
+ return cpu;
+}
+
+static u32 hv_compose_msi_req_v2(
+ struct pci_create_interrupt2 *int_pkt, int cpu,
+ u32 slot, u8 vector, u16 vector_count)
+{
int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE2;
int_pkt->wslot.slot = slot;
int_pkt->int_desc.vector = vector;
int_pkt->int_desc.vector_count = vector_count;
int_pkt->int_desc.delivery_mode = DELIVERY_MODE;
- cpu = hv_compose_msi_req_get_cpu(affinity);
int_pkt->int_desc.processor_array[0] =
hv_cpu_number_to_vp_number(cpu);
int_pkt->int_desc.processor_count = 1;
@@ -1660,18 +1710,15 @@ static u32 hv_compose_msi_req_v2(
}
static u32 hv_compose_msi_req_v3(
- struct pci_create_interrupt3 *int_pkt, const struct cpumask *affinity,
+ struct pci_create_interrupt3 *int_pkt, int cpu,
u32 slot, u32 vector, u16 vector_count)
{
- int cpu;
-
int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE3;
int_pkt->wslot.slot = slot;
int_pkt->int_desc.vector = vector;
int_pkt->int_desc.reserved = 0;
int_pkt->int_desc.vector_count = vector_count;
int_pkt->int_desc.delivery_mode = DELIVERY_MODE;
- cpu = hv_compose_msi_req_get_cpu(affinity);
int_pkt->int_desc.processor_array[0] =
hv_cpu_number_to_vp_number(cpu);
int_pkt->int_desc.processor_count = 1;
@@ -1715,12 +1762,18 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
struct pci_create_interrupt3 v3;
} int_pkts;
} __packed ctxt;
+ bool multi_msi;
u64 trans_id;
u32 size;
int ret;
+ int cpu;
+
+ msi_desc = irq_data_get_msi_desc(data);
+ multi_msi = !msi_desc->pci.msi_attrib.is_msix &&
+ msi_desc->nvec_used > 1;
/* Reuse the previous allocation */
- if (data->chip_data) {
+ if (data->chip_data && multi_msi) {
int_desc = data->chip_data;
msg->address_hi = int_desc->address >> 32;
msg->address_lo = int_desc->address & 0xffffffff;
@@ -1728,7 +1781,6 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
return;
}
- msi_desc = irq_data_get_msi_desc(data);
pdev = msi_desc_to_pci_dev(msi_desc);
dest = irq_data_get_effective_affinity_mask(data);
pbus = pdev->bus;
@@ -1738,11 +1790,18 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
if (!hpdev)
goto return_null_message;
+ /* Free any previous message that might have already been composed. */
+ if (data->chip_data && !multi_msi) {
+ int_desc = data->chip_data;
+ data->chip_data = NULL;
+ hv_int_desc_free(hpdev, int_desc);
+ }
+
int_desc = kzalloc(sizeof(*int_desc), GFP_ATOMIC);
if (!int_desc)
goto drop_reference;
- if (!msi_desc->pci.msi_attrib.is_msix && msi_desc->nvec_used > 1) {
+ if (multi_msi) {
/*
* If this is not the first MSI of Multi MSI, we already have
* a mapping. Can exit early.
@@ -1767,9 +1826,11 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
*/
vector = 32;
vector_count = msi_desc->nvec_used;
+ cpu = hv_compose_multi_msi_req_get_cpu();
} else {
vector = hv_msi_get_int_vector(data);
vector_count = 1;
+ cpu = hv_compose_msi_req_get_cpu(dest);
}
/*
@@ -1785,7 +1846,6 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
switch (hbus->protocol_version) {
case PCI_PROTOCOL_VERSION_1_1:
size = hv_compose_msi_req_v1(&ctxt.int_pkts.v1,
- dest,
hpdev->desc.win_slot.slot,
(u8)vector,
vector_count);
@@ -1794,7 +1854,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
case PCI_PROTOCOL_VERSION_1_2:
case PCI_PROTOCOL_VERSION_1_3:
size = hv_compose_msi_req_v2(&ctxt.int_pkts.v2,
- dest,
+ cpu,
hpdev->desc.win_slot.slot,
(u8)vector,
vector_count);
@@ -1802,7 +1862,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
case PCI_PROTOCOL_VERSION_1_4:
size = hv_compose_msi_req_v3(&ctxt.int_pkts.v3,
- dest,
+ cpu,
hpdev->desc.win_slot.slot,
vector,
vector_count);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-13 18:36:17 +0100