| Message ID | 20200908061141.90900-1-chenjiajun8@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | vhost-user: add separate memslot counter for vhost-user | expand |
+ Cc: Igor Mammedov <imammedo@redhat.com> + Cc: Marc-André Lureau <marcandre.lureau@redhat.com> who worked on this in the past. On Tue, Sep 08, 2020 at 02:11:41PM +0800, Jiajun Chen wrote: > Used_memslots is equal to dev->mem->nregions now, it is true for > vhost kernel, but not for vhost user, which uses the memory regions > that have file descriptor. In fact, not all of the memory regions > have file descriptor. > It is usefully in some scenarios, e.g. used_memslots is 8, and only > 5 memory slots can be used by vhost user, it is failed to hot plug > a new memory RAM because vhost_has_free_slot just returned false, > but we can hot plug it safely in fact. > > -- > ChangeList: > v2: > -eliminating useless used_memslots_exceeded variable and used_memslots_is_exceeded() API > > v1: > -vhost-user: add separate memslot counter for vhost-user > > Signed-off-by: Jiajun Chen <chenjiajun8@huawei.com> > Signed-off-by: Jianjay Zhou <jianjay.zhou@huawei.com> > --- > hw/virtio/vhost-backend.c | 14 ++++++++++++ > hw/virtio/vhost-user.c | 28 +++++++++++++++++++++++ > hw/virtio/vhost.c | 37 +++++++++++++++++++++++-------- > include/hw/virtio/vhost-backend.h | 5 +++++ > net/vhost-user.c | 7 ++++++ > 5 files changed, 82 insertions(+), 9 deletions(-) > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c > index 782b1d67d9..35eec7e166 100644 > --- a/hw/virtio/vhost-backend.c > +++ b/hw/virtio/vhost-backend.c > @@ -20,6 +20,8 @@ > #include <linux/vhost.h> > #include <sys/ioctl.h> > > +static unsigned int vhost_kernel_used_memslots; > + > static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request, > void *arg) > { > @@ -238,6 +240,16 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev, > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL); > } > > +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev) > +{ > + vhost_kernel_used_memslots = dev->mem->nregions; > +} > + > +static unsigned int vhost_kernel_get_used_memslots(void) > +{ > + return vhost_kernel_used_memslots; > +} > + > static const VhostOps kernel_ops = { > .backend_type = VHOST_BACKEND_TYPE_KERNEL, > .vhost_backend_init = vhost_kernel_init, > @@ -269,6 +281,8 @@ static const VhostOps kernel_ops = { > #endif /* CONFIG_VHOST_VSOCK */ > .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback, > .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg, > + .vhost_set_used_memslots = vhost_kernel_set_used_memslots, > + .vhost_get_used_memslots = vhost_kernel_get_used_memslots, > }; > #endif > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index 31231218dc..ec46a745fa 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -232,6 +232,7 @@ static VhostUserMsg m __attribute__ ((unused)); > > /* The version of the protocol we support */ > #define VHOST_USER_VERSION (0x1) > +static unsigned int vhost_user_used_memslots; > > struct vhost_user { > struct vhost_dev *dev; > @@ -2354,6 +2355,31 @@ void vhost_user_cleanup(VhostUserState *user) > user->chr = NULL; > } > > +static void vhost_user_set_used_memslots(struct vhost_dev *dev) > +{ > + unsigned int counter = 0; > + int i; > + > + for (i = 0; i < dev->mem->nregions; ++i) { > + struct vhost_memory_region *reg = dev->mem->regions + i; > + ram_addr_t offset; > + MemoryRegion *mr; > + int fd; > + > + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr); > + mr = vhost_user_get_mr_data(reg->userspace_addr, &offset, &fd); > + if (mr && fd > 0) { > + counter++; > + } > + } > + vhost_user_used_memslots = counter; > +} > + > +static unsigned int vhost_user_get_used_memslots(void) > +{ > + return vhost_user_used_memslots; > +} > + > const VhostOps user_ops = { > .backend_type = VHOST_BACKEND_TYPE_USER, > .vhost_backend_init = vhost_user_backend_init, > @@ -2387,4 +2413,6 @@ const VhostOps user_ops = { > .vhost_backend_mem_section_filter = vhost_user_mem_section_filter, > .vhost_get_inflight_fd = vhost_user_get_inflight_fd, > .vhost_set_inflight_fd = vhost_user_set_inflight_fd, > + .vhost_set_used_memslots = vhost_user_set_used_memslots, > + .vhost_get_used_memslots = vhost_user_get_used_memslots, > }; > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > index 1a1384e7a6..b8d617d24c 100644 > --- a/hw/virtio/vhost.c > +++ b/hw/virtio/vhost.c > @@ -45,20 +45,20 @@ > static struct vhost_log *vhost_log; > static struct vhost_log *vhost_log_shm; > > -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); > + if (hdev->vhost_ops->vhost_get_used_memslots() >= > + hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { > + return false; > + } > } > - return slots_limit > used_memslots; > + return true; > } > > static void vhost_dev_sync_region(struct vhost_dev *dev, > @@ -502,7 +502,6 @@ static void vhost_commit(MemoryListener *listener) > dev->n_mem_sections * sizeof dev->mem->regions[0]; > dev->mem = g_realloc(dev->mem, regions_size); > dev->mem->nregions = dev->n_mem_sections; > - used_memslots = dev->mem->nregions; > for (i = 0; i < dev->n_mem_sections; i++) { > struct vhost_memory_region *cur_vmr = dev->mem->regions + i; > struct MemoryRegionSection *mrs = dev->mem_sections + i; > @@ -678,6 +677,7 @@ static void vhost_region_add_section(struct vhost_dev *dev, > dev->tmp_sections[dev->n_tmp_sections - 1].fv = NULL; > memory_region_ref(section->mr); > } > + dev->vhost_ops->vhost_set_used_memslots(dev); > } > > /* Used for both add and nop callbacks */ > @@ -693,6 +693,17 @@ static void vhost_region_addnop(MemoryListener *listener, > vhost_region_add_section(dev, section); > } > > +static void vhost_region_del(MemoryListener *listener, > + MemoryRegionSection *section) > +{ > + struct vhost_dev *dev = container_of(listener, struct vhost_dev, > + memory_listener); > + if (!vhost_section(dev, section)) { > + return; > + } > + dev->vhost_ops->vhost_set_used_memslots(dev); > +} > + > static void vhost_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) > { > struct vhost_iommu *iommu = container_of(n, struct vhost_iommu, n); > @@ -1300,6 +1311,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, > hdev->memory_listener = (MemoryListener) { > .begin = vhost_begin, > .commit = vhost_commit, > + .region_del = vhost_region_del, > .region_add = vhost_region_addnop, > .region_nop = vhost_region_addnop, > .log_start = vhost_log_start, > @@ -1346,9 +1358,16 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, > memory_listener_register(&hdev->memory_listener, &address_space_memory); > QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); > > - if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { > - error_report("vhost backend memory slots limit is less" > - " than current number of present memory slots"); > + /* > + * If we started a VM without any vhost device, > + * for the first time vhost device hot-plug > + * (vhost_get_used_memslots is always 0), > + * so it needs to double check here > + */ > + if (hdev->vhost_ops->vhost_get_used_memslots() > > + hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { > + error_report("vhost backend memory slots limit is less than" > + " current number of present memory slots"); > r = -1; > if (busyloop_timeout) { > goto fail_busyloop; > diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h > index 8825bd278f..ed43a93692 100644 > --- a/include/hw/virtio/vhost-backend.h > +++ b/include/hw/virtio/vhost-backend.h > @@ -124,6 +124,9 @@ typedef int (*vhost_get_device_id_op)(struct vhost_dev *dev, uint32_t *dev_id); > > typedef bool (*vhost_force_iommu_op)(struct vhost_dev *dev); > > +typedef void (*vhost_set_used_memslots_op)(struct vhost_dev *dev); > +typedef unsigned int (*vhost_get_used_memslots_op)(void); > + > typedef struct VhostOps { > VhostBackendType backend_type; > vhost_backend_init vhost_backend_init; > @@ -168,6 +171,8 @@ typedef struct VhostOps { > vhost_vq_get_addr_op vhost_vq_get_addr; > vhost_get_device_id_op vhost_get_device_id; > vhost_force_iommu_op vhost_force_iommu; > + vhost_set_used_memslots_op vhost_set_used_memslots; > + vhost_get_used_memslots_op vhost_get_used_memslots; > } VhostOps; > > extern const VhostOps user_ops; > diff --git a/net/vhost-user.c b/net/vhost-user.c > index 17532daaf3..7e93955537 100644 > --- a/net/vhost-user.c > +++ b/net/vhost-user.c > @@ -20,6 +20,7 @@ > #include "qemu/error-report.h" > #include "qemu/option.h" > #include "trace.h" > +#include "include/hw/virtio/vhost.h" > > typedef struct NetVhostUserState { > NetClientState nc; > @@ -347,6 +348,12 @@ static int net_vhost_user_init(NetClientState *peer, const char *device, > qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, > net_vhost_user_event, NULL, nc0->name, NULL, > true); > + > + if (!vhost_has_free_slot()) { > + error_report("used memslots exceeded the backend limit, quit " > + "loop"); > + goto err; > + } > } while (!s->started); > > assert(s->vhost_net); > -- > 2.19.1
A few more comments mixed in below. Once these are addressed I'd support this change from the vhost-user side. We should get opinions from other maintainers though, particularly for the kernel backend and vhost-user-net changes. On Tue, Sep 8, 2020 at 2:11 AM Jiajun Chen <chenjiajun8@huawei.com> wrote: > > Used_memslots is equal to dev->mem->nregions now, it is true for > vhost kernel, but not for vhost user, which uses the memory regions > that have file descriptor. In fact, not all of the memory regions > have file descriptor. > It is usefully in some scenarios, e.g. used_memslots is 8, and only > 5 memory slots can be used by vhost user, it is failed to hot plug > a new memory RAM because vhost_has_free_slot just returned false, > but we can hot plug it safely in fact. > > -- > ChangeList: > v2: > -eliminating useless used_memslots_exceeded variable and used_memslots_is_exceeded() API > > v1: > -vhost-user: add separate memslot counter for vhost-user > > Signed-off-by: Jiajun Chen <chenjiajun8@huawei.com> > Signed-off-by: Jianjay Zhou <jianjay.zhou@huawei.com> > --- > hw/virtio/vhost-backend.c | 14 ++++++++++++ > hw/virtio/vhost-user.c | 28 +++++++++++++++++++++++ > hw/virtio/vhost.c | 37 +++++++++++++++++++++++-------- > include/hw/virtio/vhost-backend.h | 5 +++++ > net/vhost-user.c | 7 ++++++ > 5 files changed, 82 insertions(+), 9 deletions(-) > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index 31231218dc..ec46a745fa 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -232,6 +232,7 @@ static VhostUserMsg m __attribute__ ((unused)); > > /* The version of the protocol we support */ > #define VHOST_USER_VERSION (0x1) > +static unsigned int vhost_user_used_memslots; I worry that using a global static value may introduce a lot of edge cases which may be difficult to account for. Can we store this state per vhost_user dev, either in the VhostUserState or struct vhost_user? > > struct vhost_user { > struct vhost_dev *dev; > @@ -2354,6 +2355,31 @@ void vhost_user_cleanup(VhostUserState *user) > user->chr = NULL; > } > > +static void vhost_user_set_used_memslots(struct vhost_dev *dev) > +{ > + unsigned int counter = 0; > + int i; > + > + for (i = 0; i < dev->mem->nregions; ++i) { > + struct vhost_memory_region *reg = dev->mem->regions + i; > + ram_addr_t offset; > + MemoryRegion *mr; > + int fd; > + > + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr); This assert is redundant - vhost_user_get_mr_data already checks this. > + mr = vhost_user_get_mr_data(reg->userspace_addr, &offset, &fd); > + if (mr && fd > 0) { > + counter++; > + } > + } > + vhost_user_used_memslots = counter; > +} > + > +static unsigned int vhost_user_get_used_memslots(void) > +{ > + return vhost_user_used_memslots; > +} > + > const VhostOps user_ops = { > .backend_type = VHOST_BACKEND_TYPE_USER, > .vhost_backend_init = vhost_user_backend_init, > @@ -2387,4 +2413,6 @@ const VhostOps user_ops = { > .vhost_backend_mem_section_filter = vhost_user_mem_section_filter, > .vhost_get_inflight_fd = vhost_user_get_inflight_fd, > .vhost_set_inflight_fd = vhost_user_set_inflight_fd, > + .vhost_set_used_memslots = vhost_user_set_used_memslots, > + .vhost_get_used_memslots = vhost_user_get_used_memslots, > }; > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > index 1a1384e7a6..b8d617d24c 100644 > --- a/hw/virtio/vhost.c > +++ b/hw/virtio/vhost.c > @@ -45,20 +45,20 @@ > static struct vhost_log *vhost_log; > static struct vhost_log *vhost_log_shm; > > -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); > + if (hdev->vhost_ops->vhost_get_used_memslots() >= > + hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { > + return false; > + } > } > - return slots_limit > used_memslots; > + return true; > } > > static void vhost_dev_sync_region(struct vhost_dev *dev, > @@ -502,7 +502,6 @@ static void vhost_commit(MemoryListener *listener) > dev->n_mem_sections * sizeof dev->mem->regions[0]; > dev->mem = g_realloc(dev->mem, regions_size); > dev->mem->nregions = dev->n_mem_sections; > - used_memslots = dev->mem->nregions; > for (i = 0; i < dev->n_mem_sections; i++) { > struct vhost_memory_region *cur_vmr = dev->mem->regions + i; > struct MemoryRegionSection *mrs = dev->mem_sections + i; > @@ -678,6 +677,7 @@ static void vhost_region_add_section(struct vhost_dev *dev, > dev->tmp_sections[dev->n_tmp_sections - 1].fv = NULL; > memory_region_ref(section->mr); > } > + dev->vhost_ops->vhost_set_used_memslots(dev); > } > > /* Used for both add and nop callbacks */ > @@ -693,6 +693,17 @@ static void vhost_region_addnop(MemoryListener *listener, > vhost_region_add_section(dev, section); > } > > +static void vhost_region_del(MemoryListener *listener, > + MemoryRegionSection *section) > +{ > + struct vhost_dev *dev = container_of(listener, struct vhost_dev, > + memory_listener); > + if (!vhost_section(dev, section)) { > + return; > + } > + dev->vhost_ops->vhost_set_used_memslots(dev); > +} > + > static void vhost_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) > { > struct vhost_iommu *iommu = container_of(n, struct vhost_iommu, n); > @@ -1300,6 +1311,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, > hdev->memory_listener = (MemoryListener) { > .begin = vhost_begin, > .commit = vhost_commit, > + .region_del = vhost_region_del, > .region_add = vhost_region_addnop, > .region_nop = vhost_region_addnop, > .log_start = vhost_log_start, > @@ -1346,9 +1358,16 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, > memory_listener_register(&hdev->memory_listener, &address_space_memory); > QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); > > - if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { > - error_report("vhost backend memory slots limit is less" > - " than current number of present memory slots"); > + /* > + * If we started a VM without any vhost device, > + * for the first time vhost device hot-plug > + * (vhost_get_used_memslots is always 0), > + * so it needs to double check here NIT - There should be a period at the end of the sentence in this comment. > + */ > + if (hdev->vhost_ops->vhost_get_used_memslots() > > + hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { > + error_report("vhost backend memory slots limit is less than" > + " current number of present memory slots"); > r = -1; > if (busyloop_timeout) { > goto fail_busyloop;
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c index 782b1d67d9..35eec7e166 100644 --- a/hw/virtio/vhost-backend.c +++ b/hw/virtio/vhost-backend.c @@ -20,6 +20,8 @@ #include <linux/vhost.h> #include <sys/ioctl.h> +static unsigned int vhost_kernel_used_memslots; + static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request, void *arg) { @@ -238,6 +240,16 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev, qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL); } +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev) +{ + vhost_kernel_used_memslots = dev->mem->nregions; +} + +static unsigned int vhost_kernel_get_used_memslots(void) +{ + return vhost_kernel_used_memslots; +} + static const VhostOps kernel_ops = { .backend_type = VHOST_BACKEND_TYPE_KERNEL, .vhost_backend_init = vhost_kernel_init, @@ -269,6 +281,8 @@ static const VhostOps kernel_ops = { #endif /* CONFIG_VHOST_VSOCK */ .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback, .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg, + .vhost_set_used_memslots = vhost_kernel_set_used_memslots, + .vhost_get_used_memslots = vhost_kernel_get_used_memslots, }; #endif diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 31231218dc..ec46a745fa 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -232,6 +232,7 @@ static VhostUserMsg m __attribute__ ((unused)); /* The version of the protocol we support */ #define VHOST_USER_VERSION (0x1) +static unsigned int vhost_user_used_memslots; struct vhost_user { struct vhost_dev *dev; @@ -2354,6 +2355,31 @@ void vhost_user_cleanup(VhostUserState *user) user->chr = NULL; } +static void vhost_user_set_used_memslots(struct vhost_dev *dev) +{ + unsigned int counter = 0; + int i; + + for (i = 0; i < dev->mem->nregions; ++i) { + struct vhost_memory_region *reg = dev->mem->regions + i; + ram_addr_t offset; + MemoryRegion *mr; + int fd; + + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr); + mr = vhost_user_get_mr_data(reg->userspace_addr, &offset, &fd); + if (mr && fd > 0) { + counter++; + } + } + vhost_user_used_memslots = counter; +} + +static unsigned int vhost_user_get_used_memslots(void) +{ + return vhost_user_used_memslots; +} + const VhostOps user_ops = { .backend_type = VHOST_BACKEND_TYPE_USER, .vhost_backend_init = vhost_user_backend_init, @@ -2387,4 +2413,6 @@ const VhostOps user_ops = { .vhost_backend_mem_section_filter = vhost_user_mem_section_filter, .vhost_get_inflight_fd = vhost_user_get_inflight_fd, .vhost_set_inflight_fd = vhost_user_set_inflight_fd, + .vhost_set_used_memslots = vhost_user_set_used_memslots, + .vhost_get_used_memslots = vhost_user_get_used_memslots, }; diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 1a1384e7a6..b8d617d24c 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -45,20 +45,20 @@ static struct vhost_log *vhost_log; static struct vhost_log *vhost_log_shm; -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); + if (hdev->vhost_ops->vhost_get_used_memslots() >= + hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { + return false; + } } - return slots_limit > used_memslots; + return true; } static void vhost_dev_sync_region(struct vhost_dev *dev, @@ -502,7 +502,6 @@ static void vhost_commit(MemoryListener *listener) dev->n_mem_sections * sizeof dev->mem->regions[0]; dev->mem = g_realloc(dev->mem, regions_size); dev->mem->nregions = dev->n_mem_sections; - used_memslots = dev->mem->nregions; for (i = 0; i < dev->n_mem_sections; i++) { struct vhost_memory_region *cur_vmr = dev->mem->regions + i; struct MemoryRegionSection *mrs = dev->mem_sections + i; @@ -678,6 +677,7 @@ static void vhost_region_add_section(struct vhost_dev *dev, dev->tmp_sections[dev->n_tmp_sections - 1].fv = NULL; memory_region_ref(section->mr); } + dev->vhost_ops->vhost_set_used_memslots(dev); } /* Used for both add and nop callbacks */ @@ -693,6 +693,17 @@ static void vhost_region_addnop(MemoryListener *listener, vhost_region_add_section(dev, section); } +static void vhost_region_del(MemoryListener *listener, + MemoryRegionSection *section) +{ + struct vhost_dev *dev = container_of(listener, struct vhost_dev, + memory_listener); + if (!vhost_section(dev, section)) { + return; + } + dev->vhost_ops->vhost_set_used_memslots(dev); +} + static void vhost_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) { struct vhost_iommu *iommu = container_of(n, struct vhost_iommu, n); @@ -1300,6 +1311,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, hdev->memory_listener = (MemoryListener) { .begin = vhost_begin, .commit = vhost_commit, + .region_del = vhost_region_del, .region_add = vhost_region_addnop, .region_nop = vhost_region_addnop, .log_start = vhost_log_start, @@ -1346,9 +1358,16 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, memory_listener_register(&hdev->memory_listener, &address_space_memory); QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); - if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { - error_report("vhost backend memory slots limit is less" - " than current number of present memory slots"); + /* + * If we started a VM without any vhost device, + * for the first time vhost device hot-plug + * (vhost_get_used_memslots is always 0), + * so it needs to double check here + */ + if (hdev->vhost_ops->vhost_get_used_memslots() > + hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { + error_report("vhost backend memory slots limit is less than" + " current number of present memory slots"); r = -1; if (busyloop_timeout) { goto fail_busyloop; diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h index 8825bd278f..ed43a93692 100644 --- a/include/hw/virtio/vhost-backend.h +++ b/include/hw/virtio/vhost-backend.h @@ -124,6 +124,9 @@ typedef int (*vhost_get_device_id_op)(struct vhost_dev *dev, uint32_t *dev_id); typedef bool (*vhost_force_iommu_op)(struct vhost_dev *dev); +typedef void (*vhost_set_used_memslots_op)(struct vhost_dev *dev); +typedef unsigned int (*vhost_get_used_memslots_op)(void); + typedef struct VhostOps { VhostBackendType backend_type; vhost_backend_init vhost_backend_init; @@ -168,6 +171,8 @@ typedef struct VhostOps { vhost_vq_get_addr_op vhost_vq_get_addr; vhost_get_device_id_op vhost_get_device_id; vhost_force_iommu_op vhost_force_iommu; + vhost_set_used_memslots_op vhost_set_used_memslots; + vhost_get_used_memslots_op vhost_get_used_memslots; } VhostOps; extern const VhostOps user_ops; diff --git a/net/vhost-user.c b/net/vhost-user.c index 17532daaf3..7e93955537 100644 --- a/net/vhost-user.c +++ b/net/vhost-user.c @@ -20,6 +20,7 @@ #include "qemu/error-report.h" #include "qemu/option.h" #include "trace.h" +#include "include/hw/virtio/vhost.h" typedef struct NetVhostUserState { NetClientState nc; @@ -347,6 +348,12 @@ static int net_vhost_user_init(NetClientState *peer, const char *device, qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event, NULL, nc0->name, NULL, true); + + if (!vhost_has_free_slot()) { + error_report("used memslots exceeded the backend limit, quit " + "loop"); + goto err; + } } while (!s->started); assert(s->vhost_net);