Function vmcb_getdesc

freebsd/amd64/vmm/amd/vmcb.c:418–457

}

int
vmcb_getdesc(void *arg, int vcpu, int reg, struct seg_desc *desc)
{
	struct vmcb *vmcb;
	struct svm_softc *sc;
	struct vmcb_segment *seg;

	sc = arg;
	vmcb = svm_get_vmcb(sc, vcpu);
	seg = vmcb_segptr(vmcb, reg);
	KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
	    __func__, reg));

	desc->base = seg->base;
	desc->limit = seg->limit;
	desc->access = 0;

	if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
		/* Map seg_desc access to VMCB attribute format */
		desc->access = ((seg->attrib & 0xF00) << 4) |
		    (seg->attrib & 0xFF);

		/*
		 * VT-x uses bit 16 to indicate a segment that has been loaded
		 * with a NULL selector (aka unusable). The 'desc->access'
		 * field is interpreted in the VT-x format by the
		 * processor-independent code.
		 *
		 * SVM uses the 'P' bit to convey the same information so
		 * convert it into the VT-x format. For more details refer to
		 * section "Segment State in the VMCB" in APMv2.
		 */
		if (reg != VM_REG_GUEST_CS && reg != VM_REG_GUEST_TR) {
			if ((desc->access & 0x80) == 0)
				desc->access |= 0x10000;  /* Unusable segment */
		}
	}

	return (0);
}

#ifdef BHYVE_SNAPSHOT
int