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[Qemu-devel] [PULL 05/38] vhost: add vhost_has_free_slot() interface
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PULL 05/38] vhost: add vhost_has_free_slot() interface |
Date: |
Wed, 21 Oct 2015 13:26:42 +0300 |
From: Igor Mammedov <address@hidden>
it will allow for other parts of QEMU check if it's safe
to map memory region during hotplug/runtime.
That way hotplug path will have a chance to cancel
hotplug operation instead of crashing in vhost_commit().
Signed-off-by: Igor Mammedov <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
include/hw/virtio/vhost-backend.h | 2 ++
include/hw/virtio/vhost.h | 2 ++
hw/virtio/vhost-backend.c | 19 +++++++++++++++++++
hw/virtio/vhost-user.c | 6 ++++++
hw/virtio/vhost.c | 21 +++++++++++++++++++++
stubs/vhost.c | 6 ++++++
stubs/Makefile.objs | 1 +
7 files changed, 57 insertions(+)
create mode 100644 stubs/vhost.c
diff --git a/include/hw/virtio/vhost-backend.h
b/include/hw/virtio/vhost-backend.h
index 3a0f6e2..7d4a8ad 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -26,6 +26,7 @@ typedef int (*vhost_backend_init)(struct vhost_dev *dev, void
*opaque);
typedef int (*vhost_backend_cleanup)(struct vhost_dev *dev);
typedef int (*vhost_backend_get_vq_index)(struct vhost_dev *dev, int idx);
typedef int (*vhost_backend_set_vring_enable)(struct vhost_dev *dev, int
enable);
+typedef int (*vhost_backend_memslots_limit)(struct vhost_dev *dev);
typedef struct VhostOps {
VhostBackendType backend_type;
@@ -34,6 +35,7 @@ typedef struct VhostOps {
vhost_backend_cleanup vhost_backend_cleanup;
vhost_backend_get_vq_index vhost_backend_get_vq_index;
vhost_backend_set_vring_enable vhost_backend_set_vring_enable;
+ vhost_backend_memslots_limit vhost_backend_memslots_limit;
} VhostOps;
extern const VhostOps user_ops;
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index c3758f3..080831e 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -59,6 +59,7 @@ struct vhost_dev {
const VhostOps *vhost_ops;
void *opaque;
struct vhost_log *log;
+ QLIST_ENTRY(vhost_dev) entry;
};
int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
@@ -83,4 +84,5 @@ uint64_t vhost_get_features(struct vhost_dev *hdev, const int
*feature_bits,
uint64_t features);
void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
uint64_t features);
+bool vhost_has_free_slot(void);
#endif
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 72d1392..910d8e0 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -11,6 +11,7 @@
#include "hw/virtio/vhost.h"
#include "hw/virtio/vhost-backend.h"
#include "qemu/error-report.h"
+#include "linux/vhost.h"
#include <sys/ioctl.h>
@@ -49,12 +50,30 @@ static int vhost_kernel_get_vq_index(struct vhost_dev *dev,
int idx)
return idx - dev->vq_index;
}
+static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
+{
+ int limit = 64;
+ char *s;
+
+ if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions",
+ &s, NULL, NULL)) {
+ uint64_t val = g_ascii_strtoull(s, NULL, 10);
+ if (!((val == G_MAXUINT64 || !val) && errno)) {
+ return val;
+ }
+ error_report("ignoring invalid max_mem_regions value in vhost module:"
+ " %s", s);
+ }
+ return limit;
+}
+
static const VhostOps kernel_ops = {
.backend_type = VHOST_BACKEND_TYPE_KERNEL,
.vhost_call = vhost_kernel_call,
.vhost_backend_init = vhost_kernel_init,
.vhost_backend_cleanup = vhost_kernel_cleanup,
.vhost_backend_get_vq_index = vhost_kernel_get_vq_index,
+ .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
};
int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType
backend_type)
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index b11c0d2..9585637 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -440,6 +440,11 @@ static int vhost_user_get_vq_index(struct vhost_dev *dev,
int idx)
return idx;
}
+static int vhost_user_memslots_limit(struct vhost_dev *dev)
+{
+ return VHOST_MEMORY_MAX_NREGIONS;
+}
+
const VhostOps user_ops = {
.backend_type = VHOST_BACKEND_TYPE_USER,
.vhost_call = vhost_user_call,
@@ -447,4 +452,5 @@ const VhostOps user_ops = {
.vhost_backend_cleanup = vhost_user_cleanup,
.vhost_backend_get_vq_index = vhost_user_get_vq_index,
.vhost_backend_set_vring_enable = vhost_user_set_vring_enable,
+ .vhost_backend_memslots_limit = vhost_user_memslots_limit,
};
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index c0ed5b2..a3b4f9e 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -26,6 +26,22 @@
static struct vhost_log *vhost_log;
+static unsigned int used_memslots;
+static QLIST_HEAD(, vhost_dev) vhost_devices =
+ QLIST_HEAD_INITIALIZER(vhost_devices);
+
+bool vhost_has_free_slot(void)
+{
+ unsigned int slots_limit = ~0U;
+ struct vhost_dev *hdev;
+
+ QLIST_FOREACH(hdev, &vhost_devices, entry) {
+ unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev);
+ slots_limit = MIN(slots_limit, r);
+ }
+ return slots_limit > used_memslots;
+}
+
static void vhost_dev_sync_region(struct vhost_dev *dev,
MemoryRegionSection *section,
uint64_t mfirst, uint64_t mlast,
@@ -457,6 +473,7 @@ static void vhost_set_memory(MemoryListener *listener,
dev->mem_changed_start_addr = MIN(dev->mem_changed_start_addr, start_addr);
dev->mem_changed_end_addr = MAX(dev->mem_changed_end_addr, start_addr +
size - 1);
dev->memory_changed = true;
+ used_memslots = dev->mem->nregions;
}
static bool vhost_section(MemoryRegionSection *section)
@@ -916,6 +933,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
return -errno;
}
+ QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
+
r = hdev->vhost_ops->vhost_call(hdev, VHOST_SET_OWNER, NULL);
if (r < 0) {
goto fail;
@@ -972,6 +991,7 @@ fail_vq:
fail:
r = -errno;
hdev->vhost_ops->vhost_backend_cleanup(hdev);
+ QLIST_REMOVE(hdev, entry);
return r;
}
@@ -989,6 +1009,7 @@ void vhost_dev_cleanup(struct vhost_dev *hdev)
g_free(hdev->mem);
g_free(hdev->mem_sections);
hdev->vhost_ops->vhost_backend_cleanup(hdev);
+ QLIST_REMOVE(hdev, entry);
}
/* Stop processing guest IO notifications in qemu.
diff --git a/stubs/vhost.c b/stubs/vhost.c
new file mode 100644
index 0000000..d346b85
--- /dev/null
+++ b/stubs/vhost.c
@@ -0,0 +1,6 @@
+#include "hw/virtio/vhost.h"
+
+bool vhost_has_free_slot(void)
+{
+ return true;
+}
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index 85e4e81..ce6ce11 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -39,3 +39,4 @@ stub-obj-y += cpus.o
stub-obj-y += kvm.o
stub-obj-y += qmp_pc_dimm_device_list.o
stub-obj-y += target-monitor-defs.o
+stub-obj-y += vhost.o
--
MST
- [Qemu-devel] [PULL 00/38] vhost, pc, virtio features, fixes, cleanups, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 01/38] intel_iommu: Add support for translation for devices behind bridges, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 02/38] exec: factor out duplicate mmap code, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 03/38] net: don't set native endianness, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 04/38] tests: re-enable vhost-user-test, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 06/38] pc-dimm: add vhost slots limit check before commiting to hotplug, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 07/38] vhost: fail backend intialization early, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 05/38] vhost: add vhost_has_free_slot() interface,
Michael S. Tsirkin <=
- [Qemu-devel] [PULL 08/38] virtio: add some migration doc, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 09/38] configure: probe for memfd, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 11/38] build-sys: split util-obj- on multi-lines, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 12/38] util: add linux-only memfd fallback, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 13/38] util: add memfd helpers, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 14/38] util: add fallback for qemu_memfd_alloc(), Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 15/38] vhost: document log resizing, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 16/38] vhost: add vhost_set_log_base op, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 10/38] linux-headers: add unistd.h, Michael S. Tsirkin, 2015/10/21
- [Qemu-devel] [PULL 17/38] vhost-user: add vhost_user_requires_shm_log(), Michael S. Tsirkin, 2015/10/21