PCI: hv: Fix interrupt mapping for multi-MSI

commit a2bad844a67b1c7740bda63e87453baf63c3a7f7 upstream.

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.

5.15 backport - add hv_msi_get_int_vector helper function. Fixed merge
conflict due to delivery_mode name change (APIC_DELIVERY_MODE_FIXED
is the value given to DELIVERY_MODE on x86). Removed unused variable
in hv_compose_msi_msg. Fixed reference to msi_desc->pci to point to
the same is_msix variable.

Suggested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1652282599-21643-1-git-send-email-quic_jhugo@quicinc.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Carl Vanderlip <quic_carlv@quicinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 0200a29..9b54715 100644 (file)
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1142,6 +1142,10 @@ 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 =
@@ -1204,6 +1208,13 @@ static void hv_irq_mask(struct irq_data *data)
        pci_msi_mask_irq(data);
 }
 
+static unsigned int hv_msi_get_int_vector(struct irq_data *data)
+{
+       struct irq_cfg *cfg = irqd_cfg(data);
+
+       return cfg->vector;
+}
+
 static int hv_msi_prepare(struct irq_domain *domain, struct device *dev,
                          int nvec, msi_alloc_info_t *info)
 {
@@ -1359,12 +1370,12 @@ 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 = APIC_DELIVERY_MODE_FIXED;
 
        /*
@@ -1387,14 +1398,14 @@ 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 = APIC_DELIVERY_MODE_FIXED;
        cpu = hv_compose_msi_req_get_cpu(affinity);
        int_pkt->int_desc.processor_array[0] =
@@ -1406,7 +1417,7 @@ 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;
 
@@ -1414,7 +1425,7 @@ 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 = APIC_DELIVERY_MODE_FIXED;
        cpu = hv_compose_msi_req_get_cpu(affinity);
        int_pkt->int_desc.processor_array[0] =
@@ -1437,7 +1448,6 @@ static u32 hv_compose_msi_req_v3(
  */
 static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 {
-       struct irq_cfg *cfg = irqd_cfg(data);
        struct hv_pcibus_device *hbus;
        struct vmbus_channel *channel;
        struct hv_pci_dev *hpdev;
@@ -1446,6 +1456,8 @@ 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 {
@@ -1467,7 +1479,8 @@ 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);
@@ -1480,6 +1493,36 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
        if (!int_desc)
                goto drop_reference;
 
+       if (!msi_desc->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;
@@ -1490,7 +1533,8 @@ 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,
-                                       cfg->vector);
+                                       vector,
+                                       vector_count);
                break;
 
        case PCI_PROTOCOL_VERSION_1_2:
@@ -1498,14 +1542,16 @@ 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,
-                                       cfg->vector);
+                                       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,
-                                       cfg->vector);
+                                       vector,
+                                       vector_count);
                break;
 
        default: