motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-06 01:03:55 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

s390x/pci: Honor DMA limits set by vfio

Browse source 
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
Download patch file Download diff file Expand all files Collapse all files

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;
}