[PATCH v2 2/2] PCI: hv: Fix interrupt mapping for multi-MSI
From: Jeffrey Hugo
Date: Wed May 11 2022 - 11:23:43 EST
According to Dexuan, the hypervisor folks beleive that multi-msi
allocations are not correct. compose_msi_msg() will allocate multi-msi
one by one. However, multi-msi is a block of related MSIs, with alignment
requirements. In order for the hypervisor to allocate properly aligned
and consecutive entries in the IOMMU Interrupt Remapping Table, there
should be a single mapping request that requests all of the multi-msi
vectors in one shot.
Dexuan suggests detecting the multi-msi case and composing a single
request related to the first MSI. Then for the other MSIs in the same
block, use the cached information. This appears to be viable, so do it.
Suggested-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Signed-off-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
Reviewed-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Tested-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
---
drivers/pci/controller/pci-hyperv.c | 60 ++++++++++++++++++++++++++++++-------
1 file changed, 50 insertions(+), 10 deletions(-)
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 5e2e637..e439b81 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1525,6 +1525,10 @@ static void hv_int_desc_free(struct hv_pci_dev *hpdev,
u8 buffer[sizeof(struct pci_delete_interrupt)];
} ctxt;
+ if (!int_desc->vector_count) {
+ kfree(int_desc);
+ return;
+ }
memset(&ctxt, 0, sizeof(ctxt));
int_pkt = (struct pci_delete_interrupt *)&ctxt.pkt.message;
int_pkt->message_type.type =
@@ -1609,12 +1613,12 @@ static void hv_pci_compose_compl(void *context, struct pci_response *resp,
static u32 hv_compose_msi_req_v1(
struct pci_create_interrupt *int_pkt, struct cpumask *affinity,
- u32 slot, u8 vector)
+ u32 slot, u8 vector, u8 vector_count)
{
int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE;
int_pkt->wslot.slot = slot;
int_pkt->int_desc.vector = vector;
- int_pkt->int_desc.vector_count = 1;
+ int_pkt->int_desc.vector_count = vector_count;
int_pkt->int_desc.delivery_mode = DELIVERY_MODE;
/*
@@ -1637,14 +1641,14 @@ static int hv_compose_msi_req_get_cpu(struct cpumask *affinity)
static u32 hv_compose_msi_req_v2(
struct pci_create_interrupt2 *int_pkt, struct cpumask *affinity,
- u32 slot, u8 vector)
+ u32 slot, u8 vector, u8 vector_count)
{
int cpu;
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 = 1;
+ 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] =
@@ -1656,7 +1660,7 @@ static u32 hv_compose_msi_req_v2(
static u32 hv_compose_msi_req_v3(
struct pci_create_interrupt3 *int_pkt, struct cpumask *affinity,
- u32 slot, u32 vector)
+ u32 slot, u32 vector, u8 vector_count)
{
int cpu;
@@ -1664,7 +1668,7 @@ static u32 hv_compose_msi_req_v3(
int_pkt->wslot.slot = slot;
int_pkt->int_desc.vector = vector;
int_pkt->int_desc.reserved = 0;
- int_pkt->int_desc.vector_count = 1;
+ 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] =
@@ -1695,6 +1699,8 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
struct cpumask *dest;
struct compose_comp_ctxt comp;
struct tran_int_desc *int_desc;
+ struct msi_desc *msi_desc;
+ u8 vector, vector_count;
struct {
struct pci_packet pci_pkt;
union {
@@ -1716,7 +1722,8 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
return;
}
- pdev = msi_desc_to_pci_dev(irq_data_get_msi_desc(data));
+ 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;
hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);
@@ -1729,6 +1736,36 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
if (!int_desc)
goto drop_reference;
+ if (!msi_desc->pci.msi_attrib.is_msix && msi_desc->nvec_used > 1) {
+ /*
+ * If this is not the first MSI of Multi MSI, we already have
+ * a mapping. Can exit early.
+ */
+ if (msi_desc->irq != data->irq) {
+ data->chip_data = int_desc;
+ int_desc->address = msi_desc->msg.address_lo |
+ (u64)msi_desc->msg.address_hi << 32;
+ int_desc->data = msi_desc->msg.data +
+ (data->irq - msi_desc->irq);
+ msg->address_hi = msi_desc->msg.address_hi;
+ msg->address_lo = msi_desc->msg.address_lo;
+ msg->data = int_desc->data;
+ put_pcichild(hpdev);
+ return;
+ }
+ /*
+ * The vector we select here is a dummy value. The correct
+ * value gets sent to the hypervisor in unmask(). This needs
+ * to be aligned with the count, and also not zero. Multi-msi
+ * is powers of 2 up to 32, so 32 will always work here.
+ */
+ vector = 32;
+ vector_count = msi_desc->nvec_used;
+ } else {
+ vector = hv_msi_get_int_vector(data);
+ vector_count = 1;
+ }
+
memset(&ctxt, 0, sizeof(ctxt));
init_completion(&comp.comp_pkt.host_event);
ctxt.pci_pkt.completion_func = hv_pci_compose_compl;
@@ -1739,7 +1776,8 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
size = hv_compose_msi_req_v1(&ctxt.int_pkts.v1,
dest,
hpdev->desc.win_slot.slot,
- hv_msi_get_int_vector(data));
+ vector,
+ vector_count);
break;
case PCI_PROTOCOL_VERSION_1_2:
@@ -1747,14 +1785,16 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
size = hv_compose_msi_req_v2(&ctxt.int_pkts.v2,
dest,
hpdev->desc.win_slot.slot,
- hv_msi_get_int_vector(data));
+ vector,
+ vector_count);
break;
case PCI_PROTOCOL_VERSION_1_4:
size = hv_compose_msi_req_v3(&ctxt.int_pkts.v3,
dest,
hpdev->desc.win_slot.slot,
- hv_msi_get_int_vector(data));
+ vector,
+ vector_count);
break;
default:
--
2.7.4