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s390x/pci: Honor DMA limits set by vfio 

When an s390 guest is using lazy unmapping, it can result in a very
large number of oustanding DMA requests, far beyond the default
limit configured for vfio.  Let's track DMA usage similar to vfio
in the host, and trigger the guest to flush their DMA mappings
before vfio runs out.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[aw: non-Linux build fixes]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Matthew Rosato 2020-10-26 11:34:35 -04:00 committed by Alex Williamson
parent cd7498d07f
commit 37fa32de70
6 changed files with 117 additions and 12 deletions
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18
hw/s390x/s390-pci-bus.c
View File

@ -17,6 +17,7 @@
#include "cpu.h"
#include "hw/s390x/s390-pci-bus.h"
#include "hw/s390x/s390-pci-inst.h"
#include "hw/s390x/s390-pci-vfio.h"
#include "hw/pci/pci_bus.h"
#include "hw/qdev-properties.h"
#include "hw/pci/pci_bridge.h"
@ -764,6 +765,7 @@ static void s390_pcihost_realize(DeviceState *dev, Error **errp)
s->bus_no = 0;
QTAILQ_INIT(&s->pending_sei);
QTAILQ_INIT(&s->zpci_devs);
QTAILQ_INIT(&s->zpci_dma_limit);
css_register_io_adapters(CSS_IO_ADAPTER_PCI, true, false,
S390_ADAPTER_SUPPRESSIBLE, errp);
@ -941,17 +943,18 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
}
}
if (object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
pbdev->fh |= FH_SHM_VFIO;
} else {
pbdev->fh |= FH_SHM_EMUL;
}
pbdev->pdev = pdev;
pbdev->iommu = s390_pci_get_iommu(s, pci_get_bus(pdev), pdev->devfn);
pbdev->iommu->pbdev = pbdev;
pbdev->state = ZPCI_FS_DISABLED;
if (object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
pbdev->fh |= FH_SHM_VFIO;
pbdev->iommu->dma_limit = s390_pci_start_dma_count(s, pbdev);
} else {
pbdev->fh |= FH_SHM_EMUL;
}
if (s390_pci_msix_init(pbdev)) {
error_setg(errp, "MSI-X support is mandatory "
"in the S390 architecture");
@ -1004,6 +1007,9 @@ static void s390_pcihost_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
pbdev->fid = 0;
QTAILQ_REMOVE(&s->zpci_devs, pbdev, link);
g_hash_table_remove(s->zpci_table, &pbdev->idx);
if (pbdev->iommu->dma_limit) {
s390_pci_end_dma_count(s, pbdev->iommu->dma_limit);
}
qdev_unrealize(dev);
}
}

45
hw/s390x/s390-pci-inst.c
View File

@ -32,6 +32,20 @@
} \
} while (0)
static inline void inc_dma_avail(S390PCIIOMMU *iommu)
{
if (iommu->dma_limit) {
iommu->dma_limit->avail++;
}
}
static inline void dec_dma_avail(S390PCIIOMMU *iommu)
{
if (iommu->dma_limit) {
iommu->dma_limit->avail--;
}
}
static void s390_set_status_code(CPUS390XState *env,
uint8_t r, uint64_t status_code)
{
@ -572,7 +586,8 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra)
return 0;
}
static void s390_pci_update_iotlb(S390PCIIOMMU *iommu, S390IOTLBEntry *entry)
static uint32_t s390_pci_update_iotlb(S390PCIIOMMU *iommu,
S390IOTLBEntry *entry)
{
S390IOTLBEntry *cache = g_hash_table_lookup(iommu->iotlb, &entry->iova);
IOMMUTLBEntry notify = {
@ -585,14 +600,15 @@ static void s390_pci_update_iotlb(S390PCIIOMMU *iommu, S390IOTLBEntry *entry)
if (entry->perm == IOMMU_NONE) {
if (!cache) {
return;
goto out;
}
g_hash_table_remove(iommu->iotlb, &entry->iova);
inc_dma_avail(iommu);
} else {
if (cache) {
if (cache->perm == entry->perm &&
cache->translated_addr == entry->translated_addr) {
return;
goto out;
}
notify.perm = IOMMU_NONE;
@ -606,9 +622,13 @@ static void s390_pci_update_iotlb(S390PCIIOMMU *iommu, S390IOTLBEntry *entry)
cache->len = PAGE_SIZE;
cache->perm = entry->perm;
g_hash_table_replace(iommu->iotlb, &cache->iova, cache);
dec_dma_avail(iommu);
}
memory_region_notify_iommu(&iommu->iommu_mr, 0, notify);
out:
return iommu->dma_limit ? iommu->dma_limit->avail : 1;
}
int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra)
@ -620,6 +640,7 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra)
S390PCIIOMMU *iommu;
S390IOTLBEntry entry;
hwaddr start, end;
uint32_t dma_avail;
if (env->psw.mask & PSW_MASK_PSTATE) {
s390_program_interrupt(env, PGM_PRIVILEGED, ra);
@ -658,6 +679,11 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra)
}
iommu = pbdev->iommu;
if (iommu->dma_limit) {
dma_avail = iommu->dma_limit->avail;
} else {
dma_avail = 1;
}
if (!iommu->g_iota) {
error = ERR_EVENT_INVALAS;
goto err;
@ -675,8 +701,9 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra)
}
start += entry.len;
while (entry.iova < start && entry.iova < end) {
s390_pci_update_iotlb(iommu, &entry);
while (entry.iova < start && entry.iova < end &&
(dma_avail > 0 || entry.perm == IOMMU_NONE)) {
dma_avail = s390_pci_update_iotlb(iommu, &entry);
entry.iova += PAGE_SIZE;
entry.translated_addr += PAGE_SIZE;
}
@ -689,7 +716,13 @@ err:
s390_pci_generate_error_event(error, pbdev->fh, pbdev->fid, start, 0);
} else {
pbdev->fmb.counter[ZPCI_FMB_CNT_RPCIT]++;
setcc(cpu, ZPCI_PCI_LS_OK);
if (dma_avail > 0) {
setcc(cpu, ZPCI_PCI_LS_OK);
} else {
/* vfio DMA mappings are exhausted, trigger a RPCIT */
setcc(cpu, ZPCI_PCI_LS_ERR);
s390_set_status_code(env, r1, ZPCI_RPCIT_ST_INSUFF_RES);
}
}
return 0;
}

42
hw/s390x/s390-pci-vfio.c
View File

@ -12,7 +12,9 @@
#include <sys/ioctl.h>
#include "qemu/osdep.h"
#include "hw/s390x/s390-pci-bus.h"
#include "hw/s390x/s390-pci-vfio.h"
#include "hw/vfio/pci.h"
#include "hw/vfio/vfio-common.h"
/*
@ -52,3 +54,43 @@ retry:
return vfio_get_info_dma_avail(info, avail);
}
S390PCIDMACount *s390_pci_start_dma_count(S390pciState *s,
S390PCIBusDevice *pbdev)
{
S390PCIDMACount *cnt;
uint32_t avail;
VFIOPCIDevice *vpdev = container_of(pbdev->pdev, VFIOPCIDevice, pdev);
int id;
assert(vpdev);
id = vpdev->vbasedev.group->container->fd;
if (!s390_pci_update_dma_avail(id, &avail)) {
return NULL;
}
QTAILQ_FOREACH(cnt, &s->zpci_dma_limit, link) {
if (cnt->id == id) {
cnt->users++;
return cnt;
}
}
cnt = g_new0(S390PCIDMACount, 1);
cnt->id = id;
cnt->users = 1;
cnt->avail = avail;
QTAILQ_INSERT_TAIL(&s->zpci_dma_limit, cnt, link);
return cnt;
}
void s390_pci_end_dma_count(S390pciState *s, S390PCIDMACount *cnt)
{
assert(cnt);
cnt->users--;
if (cnt->users == 0) {
QTAILQ_REMOVE(&s->zpci_dma_limit, cnt, link);
}
}

9
include/hw/s390x/s390-pci-bus.h
View File

@ -262,6 +262,13 @@ typedef struct S390IOTLBEntry {
uint64_t perm;
} S390IOTLBEntry;
typedef struct S390PCIDMACount {
int id;
int users;
uint32_t avail;
QTAILQ_ENTRY(S390PCIDMACount) link;
} S390PCIDMACount;
struct S390PCIIOMMU {
Object parent_obj;
S390PCIBusDevice *pbdev;
@ -273,6 +280,7 @@ struct S390PCIIOMMU {
uint64_t pba;
uint64_t pal;
GHashTable *iotlb;
S390PCIDMACount *dma_limit;
};
typedef struct S390PCIIOMMUTable {
@ -348,6 +356,7 @@ struct S390pciState {
GHashTable *zpci_table;
QTAILQ_HEAD(, SeiContainer) pending_sei;
QTAILQ_HEAD(, S390PCIBusDevice) zpci_devs;
QTAILQ_HEAD(, S390PCIDMACount) zpci_dma_limit;
};
S390pciState *s390_get_phb(void);

3
include/hw/s390x/s390-pci-inst.h
View File

@ -254,6 +254,9 @@ typedef struct ClpReqRspQueryPciGrp {
#define ZPCI_STPCIFC_ST_INVAL_DMAAS 28
#define ZPCI_STPCIFC_ST_ERROR_RECOVER 40
/* Refresh PCI Translations status codes */
#define ZPCI_RPCIT_ST_INSUFF_RES 16
/* FIB function controls */
#define ZPCI_FIB_FC_ENABLED 0x80
#define ZPCI_FIB_FC_ERROR 0x40

12
include/hw/s390x/s390-pci-vfio.h
View File

@ -12,13 +12,25 @@
#ifndef HW_S390_PCI_VFIO_H
#define HW_S390_PCI_VFIO_H
#include "hw/s390x/s390-pci-bus.h"
#ifdef CONFIG_LINUX
bool s390_pci_update_dma_avail(int fd, unsigned int *avail);
S390PCIDMACount *s390_pci_start_dma_count(S390pciState *s,
S390PCIBusDevice *pbdev);
void s390_pci_end_dma_count(S390pciState *s, S390PCIDMACount *cnt);
#else
static inline bool s390_pci_update_dma_avail(int fd, unsigned int *avail)
{
return false;
}
static inline S390PCIDMACount *s390_pci_start_dma_count(S390pciState *s,
S390PCIBusDevice *pbdev)
{
return NULL;
}
static inline void s390_pci_end_dma_count(S390pciState *s,
S390PCIDMACount *cnt) { }
#endif
#endif