File 0156-s390x-pci-Honor-DMA-limits-set-by-v.patch of Package qemu-linux-user

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File 0156-s390x-pci-Honor-DMA-limits-set-by-v.patch of Package qemu-linux-user (Revision d9af3ddd80dcee94a6ad6edff7ffd394)

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From: Matthew Rosato <mjrosato@linux.ibm.com>
Date: Mon, 26 Oct 2020 11:34:35 -0400
Subject: s390x/pci: Honor DMA limits set by vfio

Include-If: %if 0%{?suse_version} == 1315
Git-commit: 37fa32de707340f3a93959ad5a1ebc41ba1520ee
References: bsc#1179725

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>
Signed-off-by: Cho, Yu-Chen <acho@suse.com>
---
 hw/s390x/s390-pci-bus.c          | 16 +++++++----
 hw/s390x/s390-pci-inst.c         | 46 +++++++++++++++++++++++++++-----
 hw/s390x/s390-pci-vfio.c         | 43 +++++++++++++++++++++++++++++
 include/hw/s390x/s390-pci-bus.h  |  9 +++++++
 include/hw/s390x/s390-pci-inst.h |  3 +++
 include/hw/s390x/s390-pci-vfio.h | 12 +++++++++
 6 files changed, 118 insertions(+), 11 deletions(-)

diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index 8814bf0766ce9d66d252558ab4d7..dc1b0ce24e9c0c3f9995449239d2 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -18,6 +18,7 @@
 #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/pci/pci_bridge.h"
 #include "hw/pci/msi.h"
@@ -762,6 +763,7 @@ 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, &local_err);
@@ -929,17 +931,18 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
             }
         }
 
+        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;
         }
 
-        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 (s390_pci_msix_init(pbdev)) {
             error_setg(errp, "MSI-X support is mandatory "
                        "in the S390 architecture");
@@ -1015,6 +1018,9 @@ 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);
+        }
         object_unparent(OBJECT(pbdev));
     }
 }
diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index f644324bcde7f86b4d2e39086ba5..73c97e5486b2f2f9396b8373d307 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -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)
 {
@@ -570,7 +584,8 @@ 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 = {
@@ -583,14 +598,15 @@ 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;
@@ -604,9 +620,14 @@ 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)
@@ -618,6 +639,7 @@ 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, 4, ra);
@@ -656,6 +678,11 @@ 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;
@@ -673,8 +700,9 @@ 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;
         }
@@ -687,7 +715,13 @@ 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;
 }
diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
index 0f2eae062f93cd2c1f5fda59c64a..0621fa386cedf3feb14f448aae91 100644
--- a/hw/s390x/s390-pci-vfio.c
+++ b/hw/s390x/s390-pci-vfio.c
@@ -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"
 
 /*
@@ -51,3 +53,44 @@ retry:
     /* If the capability exists, update with the current value */
     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);
+    }
+}
diff --git a/include/hw/s390x/s390-pci-bus.h b/include/hw/s390x/s390-pci-bus.h
index 889e630a9c8e707f126e561b93d8..4b948415fa12b8fe5b8e3b554cb7 100644
--- a/include/hw/s390x/s390-pci-bus.h
+++ b/include/hw/s390x/s390-pci-bus.h
@@ -267,6 +267,13 @@ typedef struct S390IOTLBEntry {
     uint64_t perm;
 } S390IOTLBEntry;
 
+typedef struct S390PCIDMACount {
+    int id;
+    int users;
+    uint32_t avail;
+    QTAILQ_ENTRY(S390PCIDMACount) link;
+} S390PCIDMACount;
+
 typedef struct S390PCIBusDevice S390PCIBusDevice;
 typedef struct S390PCIIOMMU {
     Object parent_obj;
@@ -279,6 +286,7 @@ typedef struct S390PCIIOMMU {
     uint64_t pba;
     uint64_t pal;
     GHashTable *iotlb;
+    S390PCIDMACount *dma_limit;
 } S390PCIIOMMU;
 
 typedef struct S390PCIIOMMUTable {
@@ -354,6 +362,7 @@ typedef struct S390pciState {
     GHashTable *zpci_table;
     QTAILQ_HEAD(, SeiContainer) pending_sei;
     QTAILQ_HEAD(, S390PCIBusDevice) zpci_devs;
+    QTAILQ_HEAD(, S390PCIDMACount) zpci_dma_limit;
 } S390pciState;
 
 S390pciState *s390_get_phb(void);
diff --git a/include/hw/s390x/s390-pci-inst.h b/include/hw/s390x/s390-pci-inst.h
index fa3bf8b5aad11e03376774f8fa41..8ee3a3c237576757f99dc1adef14 100644
--- a/include/hw/s390x/s390-pci-inst.h
+++ b/include/hw/s390x/s390-pci-inst.h
@@ -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
diff --git a/include/hw/s390x/s390-pci-vfio.h b/include/hw/s390x/s390-pci-vfio.h
index 1727292e9b5d019ac2218a54eac2..539bcf04eb5bcc29f0f54ef0cda2 100644
--- a/include/hw/s390x/s390-pci-vfio.h
+++ b/include/hw/s390x/s390-pci-vfio.h
@@ -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

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File 0156-s390x-pci-Honor-DMA-limits-set-by-v.patch of Package qemu-linux-user (Revision d9af3ddd80dcee94a6ad6edff7ffd394)

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