Skip to content

Commit

Permalink
PCI: hv: Fix interrupt mapping for multi-MSI
Browse files Browse the repository at this point in the history
commit a2bad84 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.

4.14 backport - file moved to host/pci-hyperv.c. 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 dest_Fixed). Removed unused
variable in hv_compose_msi_msg. Fixed reference to msi_desc->pci to point
to the same is_msix variable. Removed changes to compose_msi_req_v3 since
it doesn't exist yet. Added "reason" to put_pcichild (unused in function).

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>
  • Loading branch information
Jeffrey Hugo authored and Greg Kroah-Hartman committed Jul 29, 2022
1 parent aeb918b commit 7f7939e
Showing 1 changed file with 54 additions and 8 deletions.
62 changes: 54 additions & 8 deletions drivers/pci/host/pci-hyperv.c
Original file line number Diff line number Diff line change
@@ -846,6 +846,11 @@ 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 =
@@ -908,6 +913,13 @@ 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)
{
@@ -1050,12 +1062,12 @@ 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->irq_delivery_mode == dest_LowestPrio) ?
dest_LowestPrio : dest_Fixed;
@@ -1071,14 +1083,14 @@ static u32 hv_compose_msi_req_v1(

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->irq_delivery_mode == dest_LowestPrio) ?
dest_LowestPrio : dest_Fixed;
@@ -1108,7 +1120,6 @@ static u32 hv_compose_msi_req_v2(
*/
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 hv_pci_dev *hpdev;
struct pci_bus *pbus;
@@ -1117,6 +1128,8 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
unsigned long flags;
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 {
@@ -1137,7 +1150,8 @@ 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);
@@ -1149,6 +1163,36 @@ 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, hv_pcidev_ref_by_slot);
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;
@@ -1159,14 +1203,16 @@ 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:
size = hv_compose_msi_req_v2(&ctxt.int_pkts.v2,
dest,
hpdev->desc.win_slot.slot,
cfg->vector);
vector,
vector_count);
break;

default:

0 comments on commit 7f7939e

Please sign in to comment.