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diff --git a/sys/amd64/include/vmm.h b/sys/amd64/include/vmm.h
--- a/sys/amd64/include/vmm.h
+++ b/sys/amd64/include/vmm.h
@@ -231,6 +231,9 @@
/*
* APIs that modify the guest memory map require all vcpus to be frozen.
*/
+void vm_slock_memsegs(struct vm *vm);
+void vm_xlock_memsegs(struct vm *vm);
+void vm_unlock_memsegs(struct vm *vm);
int vm_mmap_memseg(struct vm *vm, vm_paddr_t gpa, int segid, vm_ooffset_t off,
size_t len, int prot, int flags);
int vm_munmap_memseg(struct vm *vm, vm_paddr_t gpa, size_t len);
diff --git a/sys/amd64/vmm/vmm.c b/sys/amd64/vmm/vmm.c
--- a/sys/amd64/vmm/vmm.c
+++ b/sys/amd64/vmm/vmm.c
@@ -46,6 +46,7 @@
#include <sys/rwlock.h>
#include <sys/sched.h>
#include <sys/smp.h>
+#include <sys/sx.h>
#include <sys/vnode.h>
#include <vm/vm.h>
@@ -185,6 +186,7 @@
uint16_t cores; /* (o) num of cores/socket */
uint16_t threads; /* (o) num of threads/core */
uint16_t maxcpus; /* (o) max pluggable cpus */
+ struct sx mem_segs_lock; /* (o) */
};
#define VMM_CTR0(vcpu, format) \
@@ -518,6 +520,7 @@
strcpy(vm->name, name);
vm->vmspace = vmspace;
mtx_init(&vm->rendezvous_mtx, "vm rendezvous lock", 0, MTX_DEF);
+ sx_init(&vm->mem_segs_lock, "vm mem_segs");
vm->sockets = 1;
vm->cores = cores_per_package; /* XXX backwards compatibility */
@@ -609,6 +612,7 @@
vmmops_vmspace_free(vm->vmspace);
vm->vmspace = NULL;
+ sx_destroy(&vm->mem_segs_lock);
mtx_destroy(&vm->rendezvous_mtx);
}
}
@@ -645,6 +649,24 @@
return (vm->name);
}
+void
+vm_slock_memsegs(struct vm *vm)
+{
+ sx_slock(&vm->mem_segs_lock);
+}
+
+void
+vm_xlock_memsegs(struct vm *vm)
+{
+ sx_xlock(&vm->mem_segs_lock);
+}
+
+void
+vm_unlock_memsegs(struct vm *vm)
+{
+ sx_unlock(&vm->mem_segs_lock);
+}
+
int
vm_map_mmio(struct vm *vm, vm_paddr_t gpa, size_t len, vm_paddr_t hpa)
{
@@ -1075,19 +1097,7 @@
vm_gpa_hold_global(struct vm *vm, vm_paddr_t gpa, size_t len, int reqprot,
void **cookie)
{
-#ifdef INVARIANTS
- /*
- * All vcpus are frozen by ioctls that modify the memory map
- * (e.g. VM_MMAP_MEMSEG). Therefore 'vm->memmap[]' stability is
- * guaranteed if at least one vcpu is in the VCPU_FROZEN state.
- */
- int state;
- for (int i = 0; i < vm->maxcpus; i++) {
- state = vcpu_get_state(vm_vcpu(vm, i), NULL);
- KASSERT(state == VCPU_FROZEN, ("%s: invalid vcpu state %d",
- __func__, state));
- }
-#endif
+ sx_assert(&vm->mem_segs_lock, SX_LOCKED);
return (_vm_gpa_hold(vm, gpa, len, reqprot, cookie));
}
diff --git a/sys/amd64/vmm/vmm_dev.c b/sys/amd64/vmm/vmm_dev.c
--- a/sys/amd64/vmm/vmm_dev.c
+++ b/sys/amd64/vmm/vmm_dev.c
@@ -221,8 +221,6 @@
vm_paddr_t gpa, maxaddr;
void *hpa, *cookie;
struct vmmdev_softc *sc;
- struct vcpu *vcpu;
- uint16_t lastcpu;
error = vmm_priv_check(curthread->td_ucred);
if (error)
@@ -233,13 +231,9 @@
return (ENXIO);
/*
- * Get a read lock on the guest memory map by freezing any vcpu.
+ * Get a read lock on the guest memory map.
*/
- lastcpu = vm_get_maxcpus(sc->vm) - 1;
- error = vcpu_lock_one(sc, lastcpu);
- if (error)
- return (error);
- vcpu = vm_vcpu(sc->vm, lastcpu);
+ vm_slock_memsegs(sc->vm);
prot = (uio->uio_rw == UIO_WRITE ? VM_PROT_WRITE : VM_PROT_READ);
maxaddr = vmm_sysmem_maxaddr(sc->vm);
@@ -256,7 +250,7 @@
* Since this device does not support lseek(2), dd(1) will
* read(2) blocks of data to simulate the lseek(2).
*/
- hpa = vm_gpa_hold(vcpu, gpa, c, prot, &cookie);
+ hpa = vm_gpa_hold_global(sc->vm, gpa, c, prot, &cookie);
if (hpa == NULL) {
if (uio->uio_rw == UIO_READ && gpa < maxaddr)
error = uiomove(__DECONST(void *, zero_region),
@@ -268,7 +262,7 @@
vm_gpa_release(cookie);
}
}
- vcpu_unlock_one(sc, lastcpu);
+ vm_unlock_memsegs(sc->vm);
return (error);
}
@@ -420,6 +414,7 @@
struct vm_readwrite_kernemu_device *kernemu;
uint64_t *regvals;
int *regnums;
+ bool memsegs_locked;
#ifdef BHYVE_SNAPSHOT
struct vm_snapshot_meta *snapshot_meta;
#endif
@@ -435,6 +430,7 @@
vcpuid = -1;
vcpu = NULL;
state_changed = 0;
+ memsegs_locked = false;
/*
* For VMM ioctls that operate on a single vCPU, lookup the
@@ -476,10 +472,6 @@
vcpu = vm_vcpu(sc->vm, vcpuid);
break;
- case VM_MAP_PPTDEV_MMIO:
- case VM_UNMAP_PPTDEV_MMIO:
- case VM_BIND_PPTDEV:
- case VM_UNBIND_PPTDEV:
#ifdef COMPAT_FREEBSD12
case VM_ALLOC_MEMSEG_FBSD12:
#endif
@@ -487,6 +479,21 @@
case VM_MMAP_MEMSEG:
case VM_MUNMAP_MEMSEG:
case VM_REINIT:
+ /*
+ * ioctls that modify the memory map must lock memory
+ * segments exclusively.
+ */
+ vm_xlock_memsegs(sc->vm);
+ memsegs_locked = true;
+ /* FALLTHROUGH */
+ case VM_MAP_PPTDEV_MMIO:
+ case VM_UNMAP_PPTDEV_MMIO:
+ case VM_BIND_PPTDEV:
+ case VM_UNBIND_PPTDEV:
+#ifdef BHYVE_SNAPSHOT
+ case VM_SNAPSHOT_REQ:
+ case VM_RESTORE_TIME:
+#endif
/*
* ioctls that operate on the entire virtual machine must
* prevent all vcpus from running.
@@ -503,14 +510,10 @@
case VM_GET_MEMSEG:
case VM_MMAP_GETNEXT:
/*
- * Lock a vcpu to make sure that the memory map cannot be
- * modified while it is being inspected.
+ * Lock the memory map while it is being inspected.
*/
- vcpuid = vm_get_maxcpus(sc->vm) - 1;
- error = vcpu_lock_one(sc, vcpuid);
- if (error)
- goto done;
- state_changed = 1;
+ vm_slock_memsegs(sc->vm);
+ memsegs_locked = true;
break;
#ifdef COMPAT_FREEBSD13
@@ -958,6 +961,8 @@
vcpu_unlock_one(sc, vcpuid);
else if (state_changed == 2)
vcpu_unlock_all(sc);
+ if (memsegs_locked)
+ vm_unlock_memsegs(sc->vm);
done:
/*
@@ -978,7 +983,6 @@
size_t len;
vm_ooffset_t segoff, first, last;
int error, found, segid;
- uint16_t lastcpu;
bool sysmem;
error = vmm_priv_check(curthread->td_ucred);
@@ -997,12 +1001,9 @@
}
/*
- * Get a read lock on the guest memory map by freezing any vcpu.
+ * Get a read lock on the guest memory map.
*/
- lastcpu = vm_get_maxcpus(sc->vm) - 1;
- error = vcpu_lock_one(sc, lastcpu);
- if (error)
- return (error);
+ vm_slock_memsegs(sc->vm);
gpa = 0;
found = 0;
@@ -1029,7 +1030,7 @@
error = EINVAL;
}
}
- vcpu_unlock_one(sc, lastcpu);
+ vm_unlock_memsegs(sc->vm);
return (error);
}
@@ -1242,7 +1243,6 @@
vm_ooffset_t first, last;
size_t seglen;
int error;
- uint16_t lastcpu;
bool sysmem;
dsc = cdev->si_drv1;
@@ -1256,16 +1256,14 @@
if ((nprot & PROT_EXEC) || first < 0 || first >= last)
return (EINVAL);
- lastcpu = vm_get_maxcpus(dsc->sc->vm) - 1;
- error = vcpu_lock_one(dsc->sc, lastcpu);
- if (error)
- return (error);
+ vm_slock_memsegs(dsc->sc->vm);
error = vm_get_memseg(dsc->sc->vm, dsc->segid, &seglen, &sysmem, objp);
KASSERT(error == 0 && !sysmem && *objp != NULL,
("%s: invalid devmem segment %d", __func__, dsc->segid));
- vcpu_unlock_one(dsc->sc, lastcpu);
+
+ vm_unlock_memsegs(dsc->sc->vm);
if (seglen >= last) {
vm_object_reference(*objp);

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