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head/sys/amd64/vmm/vmm_dev.c
| Show First 20 Lines • Show All 167 Lines • ▼ Show 20 Lines | vmmdev_lookup2(struct cdev *cdev) | ||||
| return (cdev->si_drv1); | return (cdev->si_drv1); | ||||
| } | } | ||||
| static int | static int | ||||
| vmmdev_rw(struct cdev *cdev, struct uio *uio, int flags) | vmmdev_rw(struct cdev *cdev, struct uio *uio, int flags) | ||||
| { | { | ||||
| int error, off, c, prot; | int error, off, c, prot; | ||||
| vm_paddr_t gpa; | vm_paddr_t gpa, maxaddr; | ||||
| void *hpa, *cookie; | void *hpa, *cookie; | ||||
| struct vmmdev_softc *sc; | struct vmmdev_softc *sc; | ||||
| sc = vmmdev_lookup2(cdev); | sc = vmmdev_lookup2(cdev); | ||||
| if (sc == NULL) | if (sc == NULL) | ||||
| return (ENXIO); | return (ENXIO); | ||||
| /* | /* | ||||
| * Get a read lock on the guest memory map by freezing any vcpu. | * Get a read lock on the guest memory map by freezing any vcpu. | ||||
| */ | */ | ||||
| error = vcpu_lock_one(sc, VM_MAXCPU - 1); | error = vcpu_lock_one(sc, VM_MAXCPU - 1); | ||||
| if (error) | if (error) | ||||
| return (error); | return (error); | ||||
| prot = (uio->uio_rw == UIO_WRITE ? VM_PROT_WRITE : VM_PROT_READ); | prot = (uio->uio_rw == UIO_WRITE ? VM_PROT_WRITE : VM_PROT_READ); | ||||
| maxaddr = vmm_sysmem_maxaddr(sc->vm); | |||||
| while (uio->uio_resid > 0 && error == 0) { | while (uio->uio_resid > 0 && error == 0) { | ||||
| gpa = uio->uio_offset; | gpa = uio->uio_offset; | ||||
| off = gpa & PAGE_MASK; | off = gpa & PAGE_MASK; | ||||
| c = min(uio->uio_resid, PAGE_SIZE - off); | c = min(uio->uio_resid, PAGE_SIZE - off); | ||||
| /* | /* | ||||
| * The VM has a hole in its physical memory map. If we want to | * The VM has a hole in its physical memory map. If we want to | ||||
| * use 'dd' to inspect memory beyond the hole we need to | * use 'dd' to inspect memory beyond the hole we need to | ||||
| * provide bogus data for memory that lies in the hole. | * provide bogus data for memory that lies in the hole. | ||||
| * | * | ||||
| * Since this device does not support lseek(2), dd(1) will | * Since this device does not support lseek(2), dd(1) will | ||||
| * read(2) blocks of data to simulate the lseek(2). | * read(2) blocks of data to simulate the lseek(2). | ||||
| */ | */ | ||||
| hpa = vm_gpa_hold(sc->vm, VM_MAXCPU - 1, gpa, c, prot, &cookie); | hpa = vm_gpa_hold(sc->vm, VM_MAXCPU - 1, gpa, c, prot, &cookie); | ||||
| if (hpa == NULL) { | if (hpa == NULL) { | ||||
| if (uio->uio_rw == UIO_READ) | if (uio->uio_rw == UIO_READ && gpa < maxaddr) | ||||
| error = uiomove(__DECONST(void *, zero_region), | error = uiomove(__DECONST(void *, zero_region), | ||||
| c, uio); | c, uio); | ||||
| else | else | ||||
| error = EFAULT; | error = EFAULT; | ||||
| } else { | } else { | ||||
| error = uiomove(hpa, c, uio); | error = uiomove(hpa, c, uio); | ||||
| vm_gpa_release(cookie); | vm_gpa_release(cookie); | ||||
| } | } | ||||
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